Re: Searching for a lost Macintosh TV (Texas)

[Tothwolf]

On Mon, 5 Dec 2016, Ian Finder wrote:


Props for for having a good sense of humor. It made me laugh.

Seriously though I hate to say it but your quest feels pretty damn 
futile.


I wish you luck either way, and would offer you my MacTV but it is long 
gone.


If you can provide names of unique files or something that was on the 
drive- identifiable but not sensitive- it might help you. Like I said, 
there's nothing to key off of in your original post.


I've hunted far rarer specific systems- smbx machines and the like that 
went missing from universities with good inventory control only one or 
two years ago- and had zero luck.


Also do try Low End Mac and 68kmla, this is more relevant to those 
audiences.


I'm not really looking to find a MacTV for myself, I have other Macs in 
storage which are much more useful machines. Its a novel machine, sure, 
but just not terribly useful.


I do have very detailed information of what was on the computer (I have 
that full system backup from May 24, 1998), but I do not want to post any 
of that publicly.


Given how few Macintosh TVs still exist, with the timeframe I mentioned in 
my initial post (I was told late 2010), if a MacTV sold in that part of 
Texas to a collector, the chance it might be that very computer is 
certainly greater than zero. The odds are certainly much better than they 
would be for a much more common Mac or random PC.


Of course even if it did turn up, the hard drive or files might be long 
gone. If I didn't at least post something about it though, the chance it 
might turn up with an intact hard drive would be zero ;)

Re: Searching for a lost Macintosh TV (Texas)

[Tothwolf]

On Mon, 5 Dec 2016, Ian Finder wrote:


They sold 10,000 Apple TVs. That's a lot.

You lost track of one ten years ago, and have given no real methodology 
for discerning it from any other- the number out there with OS 7.6 or 
8mb of ram will be significant.


Perhaps you should go door-to-door, or hang flyers. It would probably 
yield better results.


[Sorry Jay, but I'm going to do this on-list.]

Wow, Ian, you sure are helpful! Would you be willing to help me print up 
and distribute those fliers?




:)

Re: Black anti-static foam corrosion

[Tothwolf]

On Sat, 3 Dec 2016, Fred Cisin wrote:

On Sat, 3 Dec 2016, drlegendre . wrote:

Interesting find, thanks for posting this. I've seen this as well. with 
a batch of old ICs which had been stored (in black foam) for some 20-30 
years. The leads kind of just stayed behind in the foam.. My assumption 
was that the foam was simply hygroscopic, and held enough atmospheric 
moisture & pollutants to foster corrosion.


There are numerous black foam formulations.

I inherited some lenses (including a Leitz Tele-Elmarit 180mm (<250 
made)) that had been stored for a few decades in an essentially airtight 
case with black foam.  When I first opened the case, it seemed as though 
there was liquid in the case, with an intense vinegar? smell.  Second 
time that I opened the case, a few hours later, it was dry and crumbly, 
and the outer painted surfaces of the lenses were badly pitted and had 
to scrape bits of the foam off, but NOT at all like water damage.  It 
turned that lens from mint condition and a major rarity, into usable but 
POOR cosmetic condition (a loss of more than a thousand dollars in 
value!). (Three other cases had simply disappeared between the time my 
buddy died and the time that the county let us go through the house.)


Something similar happened with a Nikon FT2, Nikon EM, and some lenses 
after a local friend of mine passed away in 2001. The same also happened 
with his HAM radio gear, which I was supposed to get. For much of the 
radio gear, I could likely come up with the model/serial numbers too. (We 
know who took the HAM radio gear, but couldn't really do much about it.)


http://strudel.ignorelist
.com/~tothwolf/classiccmp/stolen_nikon_camera_gear.txt

Searching for a lost Macintosh TV (Texas)

[Tothwolf]

I'm not really active in any of the classic computing communities apart 
from classiccmp, so I would appreciate it if others could pass this 
message around and see if this computer ended up in the hands of a fellow 
collector.


A good friend of mine who lived in Spring, TX (north of Houston) owned a 
black Macintosh TV (1993 vintage). During a move many years ago (late 
2010), it mistakenly ended up turned in as ewaste. I only found out late 
this year (2016) that this had happened.


Given how rare/uncommon these machines are, chances are very high that it 
ended up resold on eBay or similar instead of being scrapped. I have no 
records of the serial number of the machine, but according to my archives, 
I installed Mac OS 7.6.1 on it on May 5, 1998. It was also upgraded with 
an 8MB SIMM but still had the factory hard drive.


If by some chance a fellow collector ended up with it, and if it still has 
its hard drive and files intact, my friend would really like to obtain a 
copy of her files (a disk image of the hard drive would be ideal). I 
happened to still have a backup of the machine on a zip disk from May 24, 
1998, but she had continued to use the machine off and on for many years 
after that. I would also just like to know that the machine didn't end up 
scrapped.

Re: Possibly rarest Apple 1 ever for auction

[Tothwolf]

On Sat, 23 Jul 2016, Corey Cohen wrote:

My guess is that is was a test board for Apple.  There are some weird 
mods to the ram timing with a variable cap and to the negative supply 
that looks like they were experiments to figure out the tolerances of 
the chips.  The board was wave soldered.  You can't fake that on an 
Apple-1 because of what happens to the back of the board by the 
regulators. [...]


If you mean the crinkle tin plate under the solder mask, that doesn't 
happen due to wave soldering. The heavy tin plate was applied that way in 
a separate process before the solder mask was applied to the board. It 
used to be common to do that to all sorts of boards in the 1970s-1980s. 
With modern boards, is much more common now to just leave exposed 
copper/gaps in the solder mask and allow those areas to take up solder 
from the wave soldering (or reflow) processes.

Re: heap of floppy disks

[Tothwolf]

On Fri, 22 Jul 2016, devin davison wrote:

I picked up two crates jam packed full of floppys today. Bunch of random 
old utilities in there, borland turbo asm, turbo pascal, windows for 
workgroups etc.


I found a set of disks with the DEC digital logo on them. 4-5 disks, 
says dos for the dec pc. Some utilitys too. Are these of any use to 
anyone, or is it just a stock dos install with a dec sticker on the 
disk?


There are little heaps of disks on just about every surface around here, 
i will post back with a complete list of what is here to see if anyone 
is interested in what is here. I just want some of the software off of 
the disks, i don't necessarily want to keep the two full crates of disks 
around . There is also an original copy of doom on floppy that looks to 
be complete.


I'm still on the lookout for Procomm Plus for Windows (ver 2.11) if you 
happen across that on 3.5" disks. I bought what was supposed to be a boxed 
copy off eBay years ago and it was mostly complete... box, manuals, 
license, but no disks :)

Re: Possibly rarest Apple 1 ever for auction

[Tothwolf]

On Fri, 22 Jul 2016, Corey Cohen wrote:

There were no blank boards. That's the key. The sockets were wave 
soldered by the PCB manufacturer according to Woz. There were 2 runs of 
100 boards each.


This is also an early layout board (Non NTI) but with different wave 
soldered sockets than the two known production runs which both used TI 
sockets even though they were from a different PCB house. This board is 
from the 1st PCB house that made the "byte shop" boards but has the more 
expensive and reliable RN sockets. Which implies it predates the Byte 
Shop boards because of all the evidence.


TBH, I'm not sure why people get hung up on wave soldering vs hand 
soldering. My own hand soldering is practically indistinguishable from a 
properly wave soldered board and it wouldn't be unreasonable for someone 
working at Apple to be able to hand solder boards similarly, or even for a 
prior owner of the board to have retrofitted those sockets.


When I stuff boards, I use an assembly jig and form/pre-cut component 
leads before soldering. This is how I was (re)taught to solder when I 
began working with high reliability gear (cutting leads after soldering 
can cause microfractures in the joint) and I continue to use those 
techniques. I also use supplemental flux because the flux in cored solder 
is really only sufficient for bright/clean pads and leads. I consistently 
get better results with the extra flux.

Re: Looking for old connectors

[Tothwolf]

On Sun, 10 Jul 2016, Oliver Lehmann wrote:

One is easy - J3 is a 2x10 pin 2.54mm connector which is still common 
today.

But it is higher than the usual connectors. It has a hight of 1.5cm. If you
search for the printed A-MP number (1-87456-6), you'll find the housing,
but not the soldered clips used inside this housing

http://pics.pofo.de/gallery3/index.php/S8000/S8000_boards/FINCH-Adapter-Board/IMGP9593


found:
Connectors:
http://www.mouser.de/Search/ProductDetail.aspx?R=87523-6

Housing:
http://www.mouser.de/Search/ProductDetail.aspx?R=1-87456-6


AMP used to make a lot more contact variations including solder tail and 
wire wrap versions. When Tyco bought AMP, they began rapidly discontinuing 
large numbers of products as part of their LEAN initiative. It could be 
the contacts that were originally used were some of those which were 
discontinued.


You could probably crimp the contacts onto #24 or #22 busbar wire (tinned 
solid copper) which would allow you to solder them to the board. The 
proper crimper for these type of contacts is essential and an older model 
AMP crimp tool is not terribly expensive second hand/surplus if you have 
time to wait for one to turn up.

Re: Looking for old connectors

[Tothwolf]

On Sat, 9 Jul 2016, Jon Elson wrote:

On 07/09/2016 09:18 AM, Tothwolf wrote:

On Sat, 9 Jul 2016, Mike Stein wrote:

From: "Tothwolf" <tothw...@concentric.net>

On Sat, 9 Jul 2016, Oliver Lehmann wrote:


Hi,

for rebuilding a circuit, I'm in need of 3 old connectors used on the
original board.



##

The next one is also a power plug - but I have no idea about its AMP
number or something:

http://pics.pofo.de/gallery3/index.php/S8000/S8000_boards/FINCH-Adapter-Board/IMGP9588 
http://pics.pofo.de/gallery3/index.php/S8000/S8000_boards/FINCH-Adapter-Board/IMGP9589 
http://pics.pofo.de/gallery3/index.php/S8000/S8000_boards/FINCH-Adapter-Board/IMGP9584 



These connectors are also available with gold contacts on both ends. 
For long-term reliability, these are better.


For lower voltage signal applications, yes. For supplying power, no.

Both contact surfaces must also be the same material or tin oxide will 
form on the surface of the gold plating and cause a major headache. This 
was a serious problem with 486 and earlier Pentium PCs with 30 and 72 pin 
SIMMs and it led to a number of lawsuits.

Re: Looking for old connectors

[Tothwolf]

On Sat, 9 Jul 2016, Mike Stein wrote:

From: "Tothwolf" <tothw...@concentric.net>

On Sat, 9 Jul 2016, Oliver Lehmann wrote:


Hi,

for rebuilding a circuit, I'm in need of 3 old connectors used on the
original board.



##

The next one is also a power plug - but I have no idea about its AMP
number or something:

http://pics.pofo.de/gallery3/index.php/S8000/S8000_boards/FINCH-Adapter-Board/IMGP9588
http://pics.pofo.de/gallery3/index.php/S8000/S8000_boards/FINCH-Adapter-Board/IMGP9589
http://pics.pofo.de/gallery3/index.php/S8000/S8000_boards/FINCH-Adapter-Board/IMGP9584

Its counterpart is shown here and labled with AMP, but no number:

http://pics.pofo.de/gallery3/index.php/S8000/S8000_case/Disk-Tape-Component/Secrets-S8000/DSCF0366


The header on the board appears to be a Molex KK 396 series header. The
plug on the wiring harness is an AMP MTA-156 series IDC connector. I'm not
sure why they mixed and matched connectors, but they both use the same
size pins with .156" spacing. The Molex header might retain the plug
better than the AMP header due to the friction lock.

Molex 26-60-5100 KK 396 Header, Right-Angle with Friction Lock, 10
Circuits, Tin (Sn) Plating

http://www.molex.com/molex/products/datasheet.jsp?part=active/0026605100_PCB_HEADERS.xml
http://www.molex.com/pdm_docs/sd/026605100_sd.pdf
http://www.molex.com/webdocs/datasheets/pdf/en-us/0026605100_PCB_HEADERS.pdf

AMP 640389-0 MTA-156 Friction Lock Headers - Right Angle front bend, .125"
solder tail

http://www.te.com/usa-en/product-1-640389-0.html
http://www.te.com/commerce/DocumentDelivery/DDEController?Action=showdoc=Data+Sheet%7F82056_MTA%7F0708%7Fpdf%7FEnglish%7FENG_DS_82056_MTA_0708.pdf%7F1-640389-0



The Molex version looks like it has round pins; I'd recommend 
rectangular pins with your matching connector, they're prone to overheat 
at the best of times.


Both the Molex and AMP/Tyco headers above have square pins. I use both 
series and have them in my inventory. Round pin .156" (3.96mm) headers 
have been discontinued for years due to that very issue. The flat contacts 
used in the connector shells don't make good contact with round pins since 
it offers less surface area than a square pin. As they age and oxidize, it 
gets even worse. I routinely replace older .156" round pin headers with 
modern square versions as preventative maintenance when I 
service/refurbish boards.

Re: Looking for old connectors

[Tothwolf]

On Sat, 9 Jul 2016, Oliver Lehmann wrote:


Hi,

for rebuilding a circuit, I'm in need of 3 old connectors used on the 
original board.



##

The next one is also a power plug - but I have no idea about its AMP
number or something:

http://pics.pofo.de/gallery3/index.php/S8000/S8000_boards/FINCH-Adapter-Board/IMGP9588
http://pics.pofo.de/gallery3/index.php/S8000/S8000_boards/FINCH-Adapter-Board/IMGP9589
http://pics.pofo.de/gallery3/index.php/S8000/S8000_boards/FINCH-Adapter-Board/IMGP9584

Its counterpart is shown here and labled with AMP, but no number:

http://pics.pofo.de/gallery3/index.php/S8000/S8000_case/Disk-Tape-Component/Secrets-S8000/DSCF0366


The header on the board appears to be a Molex KK 396 series header. The 
plug on the wiring harness is an AMP MTA-156 series IDC connector. I'm not 
sure why they mixed and matched connectors, but they both use the same 
size pins with .156" spacing. The Molex header might retain the plug 
better than the AMP header due to the friction lock.


Molex 26-60-5100 KK 396 Header, Right-Angle with Friction Lock, 10 
Circuits, Tin (Sn) Plating


http://www.molex.com/molex/products/datasheet.jsp?part=active/0026605100_PCB_HEADERS.xml
http://www.molex.com/pdm_docs/sd/026605100_sd.pdf
http://www.molex.com/webdocs/datasheets/pdf/en-us/0026605100_PCB_HEADERS.pdf

AMP 640389-0 MTA-156 Friction Lock Headers - Right Angle front bend, .125" 
solder tail


http://www.te.com/usa-en/product-1-640389-0.html
http://www.te.com/commerce/DocumentDelivery/DDEController?Action=showdoc=Data+Sheet%7F82056_MTA%7F0708%7Fpdf%7FEnglish%7FENG_DS_82056_MTA_0708.pdf%7F1-640389-0

Re: Repairing a Supermicro P6DLF motherboard

[Tothwolf]

On Wed, 6 Jul 2016, Tothwolf wrote:

On Tue, 5 Jul 2016, Tothwolf wrote:

The electrolytic capacitors on this particular board at locations CE1 and 
CE6 have Sanyo OS-CON 220uF 10V polymer parts (purple sleeve and appear to 
be 10SA220M) fitted and the solder work was done by hand. The joints were 
completely defluxed/cleaned, but the leads were hand sheared down into the 
solder joint. All of the other electrolytic capacitors on this board are 
Sanyo CG series 1000uF 16V (green) that were wave soldered.


I suspect two of the Sanyo CG series parts were replaced at some point by a 
prior owner with the SA series polymer parts. According to the SA series 
datasheet, the largest 10mm diameter part is 220uF 10V, which may be why 
those were installed. I haven't used one of these boards since the late 
'90s when I built a workstation with one, and I can't remember with 100% 
certainty that Supermicro didn't use a few polymer parts on these boards.


I've been able to confirm that CE1 and CE6 on the
P6DLH motherboard should be 1000uF 16V just like all the other Sanyo CG


  ^ P6DLF

series capacitors on the board. I have no idea why someone replaced 
those two on this particular board with 220uF 10V OS-CON polymer parts 
(which are in parallel with other original 1000uF capacitors), but I'll 
install the correct value for those two capacitors when I replace the 
others.

Re: Repairing a Supermicro P6DLF motherboard

[Tothwolf]

On Tue, 5 Jul 2016, Tothwolf wrote:

The electrolytic capacitors on this particular board at locations CE1 
and CE6 have Sanyo OS-CON 220uF 10V polymer parts (purple sleeve and 
appear to be 10SA220M) fitted and the solder work was done by hand. The 
joints were completely defluxed/cleaned, but the leads were hand sheared 
down into the solder joint. All of the other electrolytic capacitors on 
this board are Sanyo CG series 1000uF 16V (green) that were wave 
soldered.


I suspect two of the Sanyo CG series parts were replaced at some point 
by a prior owner with the SA series polymer parts. According to the SA 
series datasheet, the largest 10mm diameter part is 220uF 10V, which may 
be why those were installed. I haven't used one of these boards since 
the late '90s when I built a workstation with one, and I can't remember 
with 100% certainty that Supermicro didn't use a few polymer parts on 
these boards.


I've been able to confirm that CE1 and CE6 on the P6DLH motherboard should 
be 1000uF 16V just like all the other Sanyo CG series capacitors on the 
board. I have no idea why someone replaced those two on this particular 
board with 220uF 10V OS-CON polymer parts (which are in parallel with 
other original 1000uF capacitors), but I'll install the correct value for 
those two capacitors when I replace the others.

Repairing a Supermicro P6DLF motherboard

[Tothwolf]

I'm currently in the process of repairing a Supermicro P6DLF motherboard 
which suffered shipping damage and I'm trying to find anyone else who 
might have one. I can't find any photos of one of these boards online 
(except for the one I recently purchased) and the board I have shows 
possible signs of prior rework that I'm trying figure out.


The electrolytic capacitors on this particular board at locations CE1 and 
CE6 have Sanyo OS-CON 220uF 10V polymer parts (purple sleeve and appear to 
be 10SA220M) fitted and the solder work was done by hand. The joints were 
completely defluxed/cleaned, but the leads were hand sheared down into the 
solder joint. All of the other electrolytic capacitors on this board are 
Sanyo CG series 1000uF 16V (green) that were wave soldered.


I suspect two of the Sanyo CG series parts were replaced at some point by 
a prior owner with the SA series polymer parts. According to the SA series 
datasheet, the largest 10mm diameter part is 220uF 10V, which may be why 
those were installed. I haven't used one of these boards since the late 
'90s when I built a workstation with one, and I can't remember with 100% 
certainty that Supermicro didn't use a few polymer parts on these boards.


If anyone else has one of these boards and can physically check it to see 
what parts are installed, it would be really helpful. Many of the original 
Sanyo CG series parts were trashed on my board when it was shipped in one 
of those thin USPS Priority boxes, so I'm going to end up replacing all of 
them. If the two OS-CON parts turn out to be not original, I'll fit the 
correct value parts in those two locations while I'm at it.

Re: Actually we want this Packard Bell http://www.smecc.org/itemsklkljl; _3.jpg

[Tothwolf]

On Sun, 3 Jul 2016, Liam Proven wrote:

On 3 July 2016 at 05:00, Tothwolf <tothw...@concentric.net> wrote:

I think the same could probably be said for something like that 
6-processor Pentium Pro that was sold in the late 90s which had a black 
cube style case and a stand which allowed it to sit on its corner. Very 
unusual design with both the case and boards, but few people will have 
seen, let alone used one.


That sounds interesting and striking. I don't recall hearing anything 
about it. Do you have anything I could Google for? Manufacturer or model 
name or anything?


I can't recall the name now (I tried searching Google but came up empty 
too). From an architecture standpoint it was similar to an ALR 6x6 but in 
a cube that could sit on a desk. I seem to remember the cube being 
something like 14"x14"x14", but it might have been slightly larger or 
smaller.

RE: Actually we want this Packard Bell http://www.smecc.org/itemsklkljl; _3.jpg

[Tothwolf]

On Sat, 2 Jul 2016, Jay West wrote:


Ed wrote...
-
Not just any Packard Bell...  just this one.
http://www.smecc.org/itemsklkljl;_3.jpg
it  has a place  due to form and design, certainly not  performance.
-
IMOO no place at all. If it had some kind of cult following, or lots of
people remembered it, maybe.
But I doubt most people (let alone collectors) would look at that and say
"oh, I've seen that before!".

Now... maybe as an example of how hard mfg's tried to differential via
terrible case designs... ;)


I think the same could probably be said for something like that 
6-processor Pentium Pro that was sold in the late 90s which had a black 
cube style case and a stand which allowed it to sit on its corner. Very 
unusual design with both the case and boards, but few people will have 
seen, let alone used one. As far as utility goes, they are just about 
worthless now, except to someone who wants to collect one for nostalgia 
reasons.


I myself wouldn't mind finding a Packard Bell Legend I (Intel 80286) only 
because I once owned two of them (that were sold without my approval as a 
pair to someone for $100, including the VGA monitors). The same also goes 
for a Compaq Deskpro 386/20e (specifically the 'e' model) for similar 
reasons. Both machines are not something all that useful from a utility 
standpoint (I have dozens of late generation 486 and Pentium boards I 
could put in a case which would be far more useful) but would be fun to 
have just to tinker around with again.

Re: Tandy TRS0-Model 2000 Computer Monitor required

[Tothwolf]

On Wed, 29 Jun 2016, Brendan McNeill wrote:

Looking for a Tandy TRS-80 Model 2000 compute monitor.  Wikipedia 
description here:


https://en.wikipedia.org/wiki/Tandy_2000 



The monochrome is model VM-1 Monitor, the colour is CM-1 Monitor.


Does your system have the color video board installed? If not, you'll only 
be able to use the monochrome monitor. I have a Model 2000 system in the 
same state, no color video board fitted and in need of a monochrome 
monitor.

Re: USPS: Shipping

[Tothwolf]

On Mon, 1 Feb 2016, Norman Jaffe wrote:

I've had even more fun with UPS - there was a big hole punched in the 
side of a tape library that was shipped to me, completely destroying the 
library.

The hole matched the fork on a forklift truck.
UPS insisted that the hole existed before they shipped it - until it was 
pointed out that the hole was right through their shipping documents.


The very same thing happened to me with a washing machine sized box which 
contained a computer rack. The hole was large enough where one of the 
packages of mounting hardware/brackets got lost. The seller was 
non-responsive and hadn't insured it and it took me ~3 months to get $100 
out of UPS.

Re: USPS: Shipping

[Tothwolf]

On Mon, 1 Feb 2016, Guy Sotomayor wrote:

On Feb 1, 2016, at 10:30 AM, Ken Seefried <seefr...@gmail.com> wrote:

On Sun, 31 Jan 2016, Tothwolf wrote:

On Sun, 31 Jan 2016, Pete Lancashire wrote:

Spend the extra few dollars (or what your currency is) and pack it in 
very strong box. I've actually had EPROMs show up cracked in half


Seconded. The machines the USPS uses for automated sorting of mail are 
not gentle on parcels.


I'd rather strongly suggest you not us the USPS period.  In the last 6 
months or so they've flat out lost 4 items either destined to or 
shipped by me, and one item apparently (according to the tracking web 
site) sat in a sorting facility in Utah for nearly a month before 
magically showing up.  Glad it wasn't perishable.


I’ve had failures with *all* of the major shippers.

UPS tracking is a *joke*.  It tells you not where the package is but 
where it’s supposed to be.  I was tracking an IBM 3278 terminal and it 
wasn’t until the tracking said it was “on the truck for delivery” that 
they realized there was a problem.  There was not one “physical” scan of 
the package and they had no idea where it was.


I recently bought a vacuum tube tester and whatever USPS carrier happened 
to be on duty scanned it as delivered but it was nowhere to be found. 
After calling the USPS and getting the branch manager involved, it 
magically appeared the next day. Someone at the USPS had also marked out 
the tracking barcode on the label.

Re: PDP-11/03, LSI-11 KEV11-C CIS option

[Tothwolf]

On Sun, 31 Jan 2016, Pete Lancashire wrote:

On Sun, Jan 31, 2016 at 1:24 AM, Henk Gooijen  wrote:

OK, if nobody in the USA steps up, I will check where I have stored 
that little box. At least, I am pretty sure I have that chip. I can do 
that this week. Insured shipping would not cost much is it is tiny 
enough to be shipped in a "bubble envelop".


Spend the extra few dollars (or what your currency is) and pack it in a 
very strong box. I've actually had EPROMs show up cracked in half


Seconded. The machines the USPS uses for automated sorting of mail are not 
gentle on parcels. That said, even a box isn't foolproof, I had one small 
box containing 2GB registered ECC DIMMs packed in clamshells arrive that 
had clearly been run over by a forklift (none of the memory modules 
survived).


I would also strongly advise anyone who uses printed shipping labels with 
barcodes to always use a box or mailer large enough for the label to fully 
fit flat on one side. If you wrap a label around a parcel, the automated 
label and barcode scanners in the processing machines cannot read them and 
those parcels tend to get delayed, sometimes for a significant amount of 
time (the record so far for stuff sent to me with an improperly applied 
label is a little over 3 months). The absolute worst thing you can do is 
wrap a label around a round tube horizontally...the barcode readers can't 
read it and the OCR scanners can't read the address. Such parcels end up 
having to be sorted by hand.

Re: IBM 3101-12 ASCII terminal - need fuse holder

[Tothwolf]

On Fri, 29 Jan 2016, Ethan Dicks wrote:

On Fri, Jan 29, 2016 at 2:39 AM, Tothwolf <tothw...@concentric.net> wrote:

On Thu, 28 Jan 2016, Ethan Dicks wrote:

I was just gifted with an IBM 3101-12 ASCII terminal that happens to 
be missing the fuse and fuse holder.  Unlike a lot of 1960s and 1970s 
gear, it's not round.  It's square...


There aren't too many US made square panel mount fuse holders.


Indeed.  I've seen them, but they aren't ordinary.


There was another square faced panel mount fuse holder that used to be 
pretty common but I can't remember who made it. I want to say it was 
Mountain Switch but I don't think it was them. Unlike the Littelfuse 348 
series, it has a round, threaded body with a small hole in the outer edge 
of the square frame where you push a small screwdriver to release the 
cap's locking tab.



It sounds like it might be a Littelfuse 348 series.

http://www.littelfuse.com/products/fuse-blocks-fuseholders-and-fuse-accessories/fuseholders/348/348870.aspx


That looks like the thing.  Thanks!


I couldn't tell from the grainy b/w photo I found online of the rear of 
the terminal if it had a black or red fuse holder cap. They also made them 
in a few other colors, but black and red were the most common.


One thing that will differ on the current production 348 series fuse 
holder caps vs the vintage ones is they no longer have white paint for the 
inset lettering (another victim of RoHS). You can simulate the original 
effect with a white-out pen and just scratch off any excess outside the 
recessed lettering with a fingernail.

Re: IBM 3101-12 ASCII terminal - need fuse holder

[Tothwolf]

On Thu, 28 Jan 2016, Ethan Dicks wrote:

I was just gifted with an IBM 3101-12 ASCII terminal that happens to be 
missing the fuse and fuse holder.  Unlike a lot of 1960s and 1970s gear, 
it's not round.  It's square.  Is this a standard IBM thing from the 
70s/80s?  Anyone know where I could get one?  It seems to snap in and 
probably fell out at some point under its previous owner.


Also, I found only a little info on it from Googling.  Later IBM ASCII 
terminals emulated ANSI command or Wyse-50 or something.  I couldn't 
find anything on the 3101.  Is it a glass TTY or does it respond to any 
cursor positioning, etc. commands?


Thanks for any tips and info.  Worst case, I can bodge in a fuse on the 
inside, but if I can find a replacement holder, I'd like that more.


There aren't too many US made square panel mount fuse holders. It sounds 
like it might be a Littelfuse 348 series.


http://www.littelfuse.com/products/fuse-blocks-fuseholders-and-fuse-accessories/fuseholders/348/348870.aspx

Littelfuse 348007 (03480007) fuse holder cap, black
Littelfuse 348001 (03480001) fuse holder cap, red

Re: Can Windows 98SE run on an Intel I7 with SATA hard drives?

[Tothwolf]

On Thu, 28 Jan 2016, Chuck Guzis wrote:

The latest rig that I've run 98SE on is a Intel P3 (440GX) with 2GB of 
memory.  I can do it, but it took the "unofficial final service pack" to 
reduce the amount of memory to something reasonable.


Drivers, I think would be the stumbling block on modern hardware.  I'd 
use VirtualBox in any case to deal with that issue.  I've certainly done 
with other old systems.


Windows 98 worked fine with a 1.4GHz Tualatin Pentium III (socket 370) and 
i815e chipset. It also worked just fine on a Pentium 4 and I suspect would 
work with a Pentium D or Core Duo using only one CPU core.


Windows 98 was supposed to support a maximum of 2GB of memory, however it 
has a bug in the Vcache driver which causes problems unless you limit the 
memory it can use to 1 or 1.5GB.

Re: VT100 PSU smelling.

[Tothwolf]

On Sat, 23 Jan 2016, Mattis Lind wrote:

I don't have a ESR meter or similar. It is not shorted at least and 
the resistance is in the several mega ohm range when measuring in 
circuit. Are they likely to go bad in a non catastrophic way?


They can. The translucent yellow Rifa (now owned by Kemet) class X/Y 
safety capacitors in particular have a 100% failure rate and are on my 
replace-on-sight list. They usually begin to show visible signs of 
cracking in their outer casing before they finally go out with a bang. 
It seems to be due to chemical decomposition of the paper insulator 
which swells over time and causes the case to crack. I usually replace 
them with a film capacitor from Epcos of the same value and safety 
class.


This is a 0.0033 uF 1600VDC SPARAGUE capacitor. It looks nice and orange 
and there are no signs of cracks whatsoever.


What is the likelihood of this being bad?


I've seen similar Panasonic and Sprague film capacitors fail in snubbers 
used in flyback circuits, so it is certainly possible. As inexpensive and 
readily available as these parts are, when in doubt, I just replace them. 
I would probably also replace the series resistor is there is any doubt 
that it might not be reliable (I often do this for carbon comp and carbon 
film resistors used in series with the Rifa safety capacitors I replace).

Re: RIFA EMI caps [WAS: Re: VT100 PSU smelling.]

[Tothwolf]

On Sat, 23 Jan 2016, Chuck Guzis wrote:

On 01/23/2016 02:40 PM, Pontus wrote:

All I could find were new similar Kemet capacitors. Do you know if 
newer Kemet suffer from the same problem and I will regret buying them?


I usually replace the Rifa capacitors with equivalent polyester safety 
caps (X or Y rated).  Kemets are most common and work just fine.  It's 
not a bad idea, if you're in a 240AC mains country to bump the AC 
voltage rating up a bit.  I've seen too many line filters with 250VAC 
rated caps labeled for either 120 or 240V use.  That would make me 
nervous if I lived in a 240V country.


Kemet bought out Rifa and the parts from Kemet with the same P/N also use 
a paper insulator. Rifa used to tout the paper insulator as a selling 
point, but after seeing so many fail, I won't touch them, new manufacture 
or not.


I'm using Epcos brand polyester film safety capacitors as replacements. So 
far I've been able to match them up 1:1 with the correct physical sizes 
(lead spacing) and values.

RE: VT100 PSU smelling.

[Tothwolf]

On Sat, 23 Jan 2016, tony duell wrote:

Incidentally, some machines have those sealed metal cans containing 
filter capacitors, inductors and sometimes discharge resistors [2]. Has 
anyone ever had the capacitors in one of those fail?


Actually, yes. I had one fail in one of my scopes. I don't recall the 
brand/series right now, but it is apparently a known issue with that 
particular series of filters. I still need to replace the same filters in 
the other scopes since they will most like do the same thing eventually.


[2] I wish the manufacturers would print a schematic on the can, or at 
least in an available data sheet. If I measure a 1M leak to earth from 
the live pin (say), I want to know if it's a deliberate discharging 
resistor or a leaking capacitor.


Most of the IEC320 input filters I've used have a schematic on the can or 
in the datasheet. They are usually also careful to denote the 
medical-rated filters which lack the Y-type safety capacitors between the 
two supply terminals and ground.

Re: VT100 PSU smelling.

[Tothwolf]

On Sat, 23 Jan 2016, Jules Richardson wrote:

On 01/22/2016 06:26 PM, Tothwolf wrote:

The translucent yellow Rifa (now owned by Kemet) class X/Y safety 
capacitors in particular have a 100% failure rate and are on my 
replace-on-sight list. They usually begin to show visible signs of 
cracking in their outer casing before they finally go out with a bang.


It's a well-known fault, but has anyone ever known one fail and actually 
cause any damage (other than to itself)? AIUI, they're there to reduce 
noise from the device leaking back out onto the AC supply - a system 
should run quite happily without them.


I've had maybe four or five fail on me over the years, out of several 
hundred systems. They're a definite weak spot, but given that I've never 
heard of one damaging anything it's the sort of thing I'd consider doing 
only if I was carrying out some other repair work on the PSU.


I've seen blown/cooked series resistors (which I replace with metal oxide 
resistors) and sometimes a blown fuse.


I always replace them whey I'm doing other work on a psu, however I'm not 
sure I'd knowingly leave one in place since they let out a lot of smoke 
when they go.


I usually replace them with a film capacitor from Epcos of the same 
value and safety class.


Is the voltage rating on the US ones different (new vs. old)? I can't 
remember now. I know all the old UK ones seemed to be 250V, while modern 
parts were rated at 275V.


Higher voltage parts are available but they are more expensive. I've seen 
300V, 350V, 375V and even 400V safety rated parts.

Re: VT100 PSU smelling.

[Tothwolf]

On Sat, 23 Jan 2016, Mattis Lind wrote:

2016-01-23 0:32 GMT+01:00 Peter Coghlan :

R27 is part of the snubber network on the primary side of this 
forward-type SMPS PSU. But why it it getting so hot. Is it normal? I 
have completely forgotten how a VT100 smell when running...


Snubber as in a resistor in series with a capacitor across the primary?


Yes. It is a R, C, D network.

If so check the capacitor for leakage (electrical, not liquid) or being 
shorted.


I don't have a ESR meter or similar. It is not shorted at least and the 
resistance is in the several mega ohm range when measuring in circuit. 
Are they likely to go bad in a non catastrophic way?


They can. The translucent yellow Rifa (now owned by Kemet) class X/Y 
safety capacitors in particular have a 100% failure rate and are on my 
replace-on-sight list. They usually begin to show visible signs of 
cracking in their outer casing before they finally go out with a bang. It 
seems to be due to chemical decomposition of the paper insulator which 
swells over time and causes the case to crack. I usually replace them with 
a film capacitor from Epcos of the same value and safety class.

Re: Looking for 3COM 3C905-TX Drivers

[Tothwolf]

On Sat, 26 Dec 2015, Adrian Graham wrote:

On 26/12/2015 00:45, "Robert Jarratt"  wrote:

Not too long ago I picked up a DEC Venturis FX 5120. It contains a 3COM 
3C905-TX network card. There are some sites around the web that purport 
to have drivers for this card, but I am very wary of downloading 
anything from these sites.


Does anyone happen to have drivers for this card? I am not sure what 
OSs this card was supported on, so any drivers at all would be 
appreciated.


Ack! *shudders at the memory*

Horrible things, we did a LOT of those back then initially on WFW3.11 
then Win95. I battled PATHWORKS32 and fun fun fun times with 10base2 
around police stations in the north of england.


Bound to still have driver disks at work, but the 3c905 was THE de-facto 
card of the 90s for 10baseT with the DE100/DE200 (I think) for 
thick/thinwire. The 3COMs will work with the bog-standard NE1000 driver 
for DOShazy memories of swearing which I shall take to sleep since 
it's 2am here :)


Don't get the 3C905 and 3C509 mixed up though. The 3C905 is a PCI 10/100 
UTP-only card and is supported by pretty much everything. The 3C509 OTOH 
is an ISA 10mb card available in many different combinations of 10Base-2 
and 10Base-T (some also have the 10Base-5 AUI connector) which was also 
supported by pretty much everything. There were also some 3Com PCI cards 
which were 10mb only. Some of those PCI cards even had 10Base-2 (BNC) and 
10Base-5 (AUI) connectors.


I don't recall these cards being NE1000 compatible and I seem to remember 
using 3Com specific packet drivers with them for DOS applications.


I still have quite a few of the 3C905 PCI cards in use and they have been 
extremely reliable. Those that I've taken out of service in the last 
several years have only been to free up the PCI slot for a mutli-port nic.


As far as drivers for the 3C905 go, they are on the HP site or FTP server 
somewhere. HP gobbled up 3Com quite a number of years ago.

Re: Looking for 3COM 3C905-TX Drivers

[Tothwolf]

On Sat, 26 Dec 2015, Robert Jarratt wrote:

Not too long ago I picked up a DEC Venturis FX 5120. It contains a 3COM 
3C905-TX network card. There are some sites around the web that purport 
to have drivers for this card, but I am very wary of downloading 
anything from these sites.


Does anyone happen to have drivers for this card? I am not sure what OSs 
this card was supported on, so any drivers at all would be appreciated.


These were extremely difficult to find, but try these links.

At a minimum you'll want 3c90x1.exe and 3c90x2.exe files which are 
self-extracting lha archives to create the two 3.5" disk images for the 
Etherdisk XL package. It had been many years since I went looking for this 
stuff and HP is not making it easy to find now. I suspect it would be even 
more difficult (if not impossible) to find older Etherdisk packages for 
even older network cards.


Expand the 'Archived' section at this link:
https://h10145.www1.hpe.com/downloads/SoftwareReleases.aspx?ProductNumber=JF003A

3c90x1.exe
https://h10145.www1.hpe.com/downloads/DownloadSoftware.aspx?SoftwareReleaseUId=6097=JF003A=

3c90x2.exe
https://h10145.www1.hpe.com/downloads/DownloadSoftware.aspx?SoftwareReleaseUId=6098=JF003A=

RE: EAI TR-10 Patch Plugs

[Tothwolf]

On Mon, 21 Dec 2015, Dave G4UGM wrote:

On Sun, 20 Dec 2015, Charles Anthony wrote:

Or, rather then cutting it, remove the inside threads on the shell, and 
glue it back on to the plug, rather than screwing it on.


That’s about the best method, but there is not much room for extra lead 
to push back into the plug...


I really wonder how these were made originally they look so neat...


One of the plugs in the photo looks like it might have a small roll pin or 
setscrew holding it together. The photographer didn't have it directly 
facing the camera and may have intentionally not photographed that side of 
the plugs for aesthetic reasons.

Re: Mystery IC: Allen Bradley 314B102

[Tothwolf]

On Tue, 15 Dec 2015, Mike Ross wrote:

On Tue, Dec 15, 2015 at 4:59 AM, tony duell  wrote:

This board does not look that complicated and all the ICs have known 
numbers on them (mostly TTL logic). If it were mine I'd trace out the 
schematic.


That's true and possible. I'm in two minds on this thing:

- intention was to rip all this out and convert it to a full I/O serial 
terminal, using an Arduino-based setup that Lawrence Wilkinson has 
already built and tested: 
https://www.flickr.com/photos/ljw/sets/72157632841492802/with/9201494189/
- all the keyboard contacts are already in there, Western I/O just cut 
the IBM wires off when they ripped the IBM guts out and converted it 
printer-only. I'd like to figure out the interface that's presently in 
it, just to check out the mechanism, and for that 'ah ha!' moment :)
- but I don't want to spend any significant time on it if I'm just going 
to rip it all out.


- but, although the Western I/O conversion 'butchered' a perfectly good 
IBM 2970, it IS a rare representative of that era, when all kinds of 
Selectric conversions were commonplace. So perhaps, as a nod to that 
era, it should be left as-is, as a preserved example? What say people? 
I've seen posts on old lists where people have referred to buying these 
back in the day - converted Selectrics I mean - and seeing 'mountains' 
of them in warehouses. They were once common. Where have they all gone? 
Is mine the *only* survivor from those mountains of 3rd-party backstreet 
conversions? Does anyone else have any?


I have one of these print-only IBM Selectrics that I got along with a 
TRS-80 model 1 which may very well be one of these modified IBM 2970 
Reservation Terminals. It was interfaced to the TRS-80 via a "Micromatic 
80" interface connected to the computer's parallel port. From what I 
remember, it has both a serial and parallel input and has a third 
connector which the Selectric connects to using a card-edge type 
connector.


The Micromatic 80 itself seems to mainly be made of 7400 series logic 
chips but may also have a few proms.


If there is sufficient interest, I could strip the parts from the 
interface board and scan the bare board (double sided). It is already in 
my to-do project queue anyway as I was planning to replace the 3 edge wipe 
IC sockets (most of the ICs are soldered directly to the board) and the 
original aluminum electrolytic capacitors.

Re: tool for installing pin in PCB extractors?

[Tothwolf]

On Sat, 24 Oct 2015, Chuck Guzis wrote:

On 10/24/2015 09:49 PM, Eric Smith wrote:


What tool does one use to install the metal pin into a plastic PCB
extractor, e.g., the Bivar CP-36 or Keystone 8642?


There are expensive tools for the purpose, but I've always just used a pair 
of long-nose pliers to compress the end of the spring pin slightly to get it 
started, then drive it home with a soft-faced mallet.  Make sure that the 
body of the extractor is supported.


To remove, an appropriately-sized roll pin punch works just fine without 
mangling things.


I have a small pair of specialty pliers which were made to install roll 
pins in relays which work equally well for this. Another tool I've used in 
the past is a really small c-clamp.


I don't know if anyone else has tried them yet, but I recently discovered 
that Richco/Essentra also makes card ejectors/extractors.

http://us.essentracomponents.com/shop/en-US/essentracomponentsus/pcb---electronics-hardware-44556--1/card-guides---pullers-75066--1/card-ejectors--extractors---pullers-132571--1

Re: Speaking of reproductions..

[Tothwolf]

On Sat, 24 Oct 2015, Brad wrote:

I was checking out the Altair 8800 kit online (really cool).  But I am 
hoping to one day find a kit or plans to build a Mark-8 replica, since 
I'm so deep into Radio Electronics features.  I know there was a kit out 
there (Obtronix?).  Was it any good?  Do I need someone to make a new 
kit or is the Mark 8 within the realm of the home hobbyist the way the 
TVT was?  Ie. were there ever foil patterns available for those boards 
or did the kit maker reverse engineer from originals?  Is there any 
likelihood of finding one of the replica kits still out there (I 
remember seeing one offered for $2000 on Fleabay once.. )


The patterns for most of the Mark-8 pc boards were published in Radio 
Electronics (except for maybe the cassette interface?). I'm not aware of 
anyone who has redrawn them having made their versions freely available 
however. There have been a few people in the past who have offered 
unpopulated reproduction pc boards at significant cost, but they were 
beyond my budget for such a hobby project.

RE: Opening a DECserver 90M External PSU

[Tothwolf]

On Sun, 18 Oct 2015, Robert Jarratt wrote:

I had another go today, but I fail to see how you managed to pry this 
thing apart without causing much more damage than appears in your photo. 
What kind of tool did you use?


My usual technique to deal with these sort of brick and wall-wart PSUs 
that are glued together is to carefully squeeze their plastic sides in a 
small padded vise to break the glue joint. With practice, you can split 
one of these open with little to no damage. Don't be tempted to use a 
mallet as you could with really old linear transformer wall-warts though. 
The g-forces generated by a mallet will break components off of a pc board 
in a switchmode PSU.

Re: Q-bus I/O project

[Tothwolf]

On Fri, 9 Oct 2015, John Wilson wrote:

On Fri, Oct 09, 2015 at 09:48:18PM -0500, Jay Jaeger wrote:

Do U17,U15,U10,U6 perhaps have some solder bridges, or is that just 
some flux hanging around?


It's flux, but thanks for the heads-up!  I went over everything with 
liquid-flux-soaked solder-wick and a stereo microscope ... there were a 
ton of solder bridges before. Scrubbing the board in alcohol and then 
water gets 99% of the flux off, but turns the remainder white.  Now I've 
scraped most of it out with a razor blade.


Also, I think I have ninjas.  Cooking this board let out an unusually 
large cloud of vile rosin smoke, and until I aired the house out, there 
were weird thumps and bumps coming from every corner but there was 
nothing there when I turned to look.


Was your solder paste too old perhaps? I generally use a liquid RMA type 
flux from Kester or Alpha since I mainly do hand assembly/rework, however 
I have had issues in the past removing residues from certain "no-clean" 
fluxes.


My own cleaning technique is usually an initial scrub with a plastic 
bristle brush continually re-wetted with clean isopropyl from a dispenser 
pump bottle. After getting all the flux deposits loose, and not letting 
the board dry in between, I rinse with either isopropyl or water from a 
wash bottle over a glass tray. If any residue remains, a second cleaning 
almost always seems to get rid of it.


One important thing I have noticed though is not to let flux sit on the 
board for too long. As the solvent carriers in it evaporate, it hardens up 
more and more which makes it all the more difficult to clean. After a few 
days to a week, it takes a lot more work to get the flux residue off.

Re: Compaq Portable II - IDE compatibility (and setup disk image)

[Tothwolf]

On Mon, 5 Oct 2015, Jules Richardson wrote:

My Portable II uses a Miniscribe ST506/412 drive hooked up to a bridge 
board that I'm told is IDE at the other side, back to the controller. 
The original drive in my machine is toast - I had to pop the lid to free 
the spindle. It spins up now, and might cough up some data (for a 
while), so intention is two-fold:


1) Put the original drive and bridge board into a more modern system to 
attempt a read,


2) Replace the original drive/bridge combo with a more modern IDE drive 
(happy to waste 99% of the space on it...)


Are there any gotchas involved to either of these, given that IDE was 
presumably in its infancy when the system was current, and so its 
possibly a slightly different animal to a more modern version? I don't 
want to fry the Compaq's controller, or the bridge board.


In addition to this, the machine's lost its config, so currently 
defaults to a floppy boot. Does anyone happen to have an image of the 
360K setup floppy, either in Imagedisk or raw format? (LLF is presumably 
512 byte sectors, 9 sectors/track, and 40 tracks per side?)


If you know the Softpaq number, I can see if I have the configuration disk 
in my archives. It would have been located in ftp.compaq.com/pub/softpaq/ 
however at some point most of the files in sp-0500/ and sp0501-1000/ 
at least seem to have disappeared. I have copies of these that I happened 
to archive back when I regularly serviced Compaq systems (although I do 
not have copies of all of the much much larger softpaq subdirectories).

Re: Compaq Portable II - IDE compatibility (and setup disk image)

[Tothwolf]

On Tue, 6 Oct 2015, Tothwolf wrote:

On Mon, 5 Oct 2015, Jules Richardson wrote:

My Portable II uses a Miniscribe ST506/412 drive hooked up to a bridge 
board that I'm told is IDE at the other side, back to the controller. 
The original drive in my machine is toast - I had to pop the lid to 
free the spindle. It spins up now, and might cough up some data (for a 
while), so intention is two-fold:


1) Put the original drive and bridge board into a more modern system to 
attempt a read,


2) Replace the original drive/bridge combo with a more modern IDE drive 
(happy to waste 99% of the space on it...)


Are there any gotchas involved to either of these, given that IDE was 
presumably in its infancy when the system was current, and so its 
possibly a slightly different animal to a more modern version? I don't 
want to fry the Compaq's controller, or the bridge board.


In addition to this, the machine's lost its config, so currently 
defaults to a floppy boot. Does anyone happen to have an image of the 
360K setup floppy, either in Imagedisk or raw format? (LLF is 
presumably 512 byte sectors, 9 sectors/track, and 40 tracks per side?)


If you know the Softpaq number, I can see if I have the configuration 
disk in my archives. It would have been located in 
ftp.compaq.com/pub/softpaq/ however at some point most of the files in 
sp-0500/ and sp0501-1000/ at least seem to have disappeared. I have 
copies of these that I happened to archive back when I regularly 
serviced Compaq systems (although I do not have copies of all of the 
much much larger softpaq subdirectories).


While I don't know if it is fully intact, there seems to be a more 
complete copy here: ftp.hp.com/pub/softpaq/sp-0500/

RE: Troubleshooting a 286.. oscope level!

[Tothwolf]

On Sat, 3 Oct 2015, et...@757.org wrote:

I might be able to get hold of the bios, but I'm worried about the 3rd 
EPROM. It sits in the middle of a bunch of Yamaha branded chips. The 
BIOS chips are in the middle of a Chips & Technologies 286 chipset 
group. The people I find might be able to dump the BIOS via dos program 
but not that 3rd IC. But at least if I could split the one I could 
compare it.


Here are mainboard pics I took when doing the cap replacement:
http://imgur.com/a/CQHcy
I might recheck that mess near C113


Did you only replace those small green Nichicon parts? If so, I would 
inspect/test the others as well. My experience with these type of early 
mixed SMD/through-hole boards is that some companies tried to reflow them 
with the small electrolytics already in place which would damage their 
seals and cause them to leak as they aged. It doesn't seem to be specific 
to any particular brand/series either as I've seen Nichicon, Nippon, 
Panasonic, etc all affected by this.


If a new set of BIOS EPROMs doesn't fix it, it might be time to look into 
an in circuit emulator for the 80286. PODs for LCC sockets do exist, 
although they might be harder to find than a POD for the PLCC or PGA 
versions.

RE: ESR Meter Recommendations

[Tothwolf]

On Wed, 30 Sep 2015, Jay West wrote:

Question - I could be mistaken, but I think someone mentioned that these 
were not good for testing caps that had a higher operating voltage. Is 
that correct? My understanding was that the testing method used by this 
ESR meter was valid for most all the large electrolytics...?


You can measure the ESR of any capacitor, however for large filter 
capacitors, a leakage tester is likely to be more important.

Re: ESR Meter Recommendations

[Tothwolf]

On Wed, 30 Sep 2015, John Robertson wrote:

On 09/29/2015 2:59 PM, Jay West wrote:


This is the one I have used for years.

http://clientes.netvisao.pt/greenpal/evb1.htm

About $88 USD


That is an authorized Bob Parker variation of his original Dick Smith 
ESR meter kit. On this side of the pond they were made by Anatek until 
the owner was killed in an accident, then the series (now called the 
Blue ESR) is made by Alltronics and sold by dealers such as I. These all 
use Bob's licensed code, just different box and PCB layouts.


If you want a Blue ESR I sell them on my web site's catalogue section, 
or you can order the EVB from Portugal if you are on the east side of 
the pond.


I've been selling variations (evolution by intelligent design) of Bob's 
ESR meter kit since 1999!


I bought a kit from anatekcorp.com last year to replace my Dick Smith 
version that spouted legs and was rather disappointed with how it had been 
kitted up. A lot of the components were very low quality or did not fit 
the board properly, so I substituted my own. Even the 9V battery snap was 
made wrong (bad quality wire and the snap was made backwards). Another 
oddity was the kit included two 18 pin dip sockets instead of an 18 pin 
and a 16 pin (I used some 3M dual wipe sockets that I had anyway).


One thing that really bothered me about the 'Blue ESR' variation compared 
to the original Dick Smith version was the lack of banana jacks, however I 
found some shrouded jacks which fit the blue Hammond enclosure.


If there is any interest in the changes I made to my meter, I'll see about 
digging up my notes/parts list and the photos I took during assembly.

Re: ESR Meter Recommendations

[Tothwolf]

On Wed, 30 Sep 2015, John Robertson wrote:

On 09/30/2015 5:22 PM, Tothwolf wrote:

I bought a kit from anatekcorp.com last year to replace my Dick Smith 
version that spouted legs and was rather disappointed with how it had 
been kitted up. A lot of the components were very low quality or did 
not fit the board properly, so I substituted my own. Even the 9V 
battery snap was made wrong (bad quality wire and the snap was made 
backwards). Another oddity was the kit included two 18 pin dip sockets 
instead of an 18 pin and a 16 pin (I used some 3M dual wipe sockets 
that I had anyway).


One thing that really bothered me about the 'Blue ESR' variation 
compared to the original Dick Smith version was the lack of banana 
jacks, however I found some shrouded jacks which fit the blue Hammond 
enclosure.


If there is any interest in the changes I made to my meter, I'll see 
about digging up my notes/parts list and the photos I took during 
assembly.


The new kit makers seem to be doing a good job on fitting the kits out 
properly, had a little trouble with the first batch and they quickly 
sent me missing parts. Heck, I remember problems I had with Dick Smith 
kits back in the early 00s - missing circuit boards, wrong parts, etc. 
However DS (and Anatek) ALWAYS made good on shortages.


It wasn't really a case of missing parts, just really poor quality parts 
apparently purchased in bulk based on price and little else (which may 
also be the reason why my kit had two 18 pin sockets in it). Some of the 
parts also looked suspiciously like the really junk stuff you find from 
the far-east eBay resellers. The capacitors they included did not match 
the lead spacing on the board (cheaper off-brand 5mm dia, 2mm ls parts 
instead of low profile 6.3mm dia 2.5mm ls), although I had no trouble at 
all finding the correct low-profile parts from Mouser that the board 
seemed to be designed for (IIRC, Nichicon SA and SR series electrolytics). 
Even the trimmer resistors were the wrong format for the board, which I 
replaced with some high quality Bourns parts that fit perfectly. Heck, 
even the Omron button cap was selected based on price...a tiny square cap 
intended to poke through a round hole? I used a larger round button cap 
from Omron.


Plus Bob Parker is still helping folks with his kit, he has a great 
support site in AU for these kits.


http://members.ozemail.com.au/~bobpar/esrmeter.htm (note the lack of 
twitter or facebook links - "This web page is for grownups"!)


FYI the kit leads have banana sockets on them...so you can quick connect 
the optional probes or use your own.


...yeah. About that...those leads and banana plugs are *terrible*. 
Absolutely junk. [Not to mention if you plug the "banana plugs" they 
include into the test probes they offer, there is no safety shroud at the 
plug to probe connection.] The little short wires they included were 
kinked, sticky, and were /never/ going to work out well. Maybe they would 
be find for a hobbyist who uses the tool every once in awhile, but for 
daily use? No way.


I also wanted to be able to use my Probe Master and Parrot Clip test leads 
with it. The original Dick Smith version had banana jacks, although they 
weren't shrouded and weren't standard 0.75" spacing, however the shrouded 
jacks I added to my Blue ESR meter are standard 0.75" spacing, so I can 
use double-banana plugs with them if I want to.


I took lots of photos and notes with the intent to write up a full 
critical review of it, but I've just been too busy with other projects. My 
personal opinion is the fit and finish of the Blue ESR meter out of the 
box isn't up to par and they charge way too much for the kit to be 
substituting in low quality components.

Re: One more try - Can you ID this S-100 Serial board?

[Tothwolf]

On Wed, 30 Sep 2015, jwsmobile wrote:

I couldn't spot how they did level shifting to RS232 levels.  The SI 
signal appears to go to a 7400 next to one of the Uarts.


One of the Uarts is one which requires it would seem 12 v as well, but 
it doesn't do the levels for rs232 (AY-3-1015)


I'd need sharper images and possession of the board to peer at it for an 
hour or so to try to figure it out.


Also the edge card space from the dual 50 pin headers seem to be 
suspicious. i don't have an S100 spec to look at handy, but I was going 
to see if there is any decoding going on, or maybe this is just a buffer 
board to go to another system.  There seems to be a lot of LS244 and so 
forth going on on the way to the edge card connectors, which smells more 
like a buffer board than a serial board.  that is is not populated but 
for the two 10 pin connectors is more interesting.


Maybe someone else will figure out more or know more.


The resistor networks connected to those traces are also not populated.

Wonder what the deal is with the missing C2 right next to the crystal 
though? Broken off?

Re: Small glass capacitors polarized?

[Tothwolf]

On Sun, 27 Sep 2015, Noel Chiappa wrote:


> From: drlegendre

> I'm not sure what you're describing. Can you link to a pic of one of 
> these caps?


http://www.electrical4u.com/images/glass-capacitor.jpg


These are hermetically sealed ceramic and are non-polarized. The glass 
encapsulation made them more expensive so they were usually only used in 
high reliability, aerospace, military, etc type applications. There are 
also similar sized axial ceramics which are epoxy dipped which are not 
hermetically sealed.


One downside is like glass encapsulated diodes, you have to be careful to 
support their leads at the capacitor's body while forming to avoid 
cracking their glass shell. Also like with glass encapsulated diodes, they 
should be covered with clear heatshrink if the board will be conformal 
coated.


As for wound foil capacitor types, they sort of have polarity. In audio 
and other noise sensitive applications, the outside foil end of the 
capacitor should be connected to ground or the lower potential side of the 
circuit. You also can't go by the black band printed on new manufacture 
parts as it does not actually indicate the outside foil end (they are 
printed randomly). When I briefly mentioned these before, someone pointed 
me to this video which goes into more detail. 
https://www.youtube.com/watch?v=BnR_DLd1PDI

Re: IBM 026

[Tothwolf]

On Sat, 19 Sep 2015, Able Baker wrote:

On Fri, 18 Sep 2015, Todd Goodman wrote:

On Fri, 18 Sep 2015, Noel Chiappa wrote:

Well, here's an 029 (not quite what the OP was looking for, but good 
enough for you all, I expect) for a not insane amount of money: 
http://www.ebay.com/itm/281796720725


So I see this sold - anyone know who got it?


Yes.  I did.  I'll let people know what's up when I receive it.  Though 
i don't expect to get much time with it for a while.


Some people have more money than common cents...However, you only 
overpaid for it by about $800.As scrap metal it's probably worth about 
$99.99


If you really wanted it that badly then you should've bought it.

Re: Keys resurfaces

[Tothwolf]

While I've not yet completely forgiven Mr. Keys for swiping a van load of 
VAX systems (including a bunch of MicroVAX 3100, 4000/VLC, etc) over a 
decade ago when I had offered him some wide format printers and large 
monitors, I'm willing to talk to him and see what can be done if others 
are also interested in this.



On Fri, 4 Sep 2015, Al Kossow wrote:


Saw this in AFC

Another water damaged collection heading to the landfill

--

Subject: Houston (and everywhere else), we have ... an opportunity
From: hlctmi...@gmail.com
Injection-Date: Thu, 03 Sep 2015 15:37:06 +

My name is John Keys, and I incorporated the Houston Computer Museum in May=
2003 as 501(c)(3) non-profit.

I've been good at collecting things.  I've have various PDPs, an HP3000, SE=
L 810A, SDS 910, and a Cray YMP/EL8.  I have an IBM 083 card sorter and sev=
eral keypunchs (models 024, 026, 029 and 129).  I have over 1,200 books and=
manuals.  And those are just a small sample.

That's the good news.

The bad news is that it's all in storage, in my home, or in a 3,300 square-=
foot warehouse.  I don't have exhibit space.  You might have heard that it =
rains in Houston;  the warehouse has flood damage that needs to be mitigate=
d.

I haven't been good at getting the 21st century to work for me, and this is=
where you come in.  I need a functional web page, one that makes it easier=
for people to donate online.  I need a contact email link that works.

If you can help me get this done, I'd be grateful.

What's at stake?  I'm 70 years old, and if I can't make a go of this, all t=
hat equipment will get recycled or hauled off for scrap or dumped in a land=
fill.  And all of that documentation will go with it.

If you can help me with web hosting and web page design, let me know.  Advi=
ce is nice -- I've had lots of it -- but what I really need is people who c=
an step up and do what I haven't done. I need help in cleaning all these ar=
tifacts that were damaged by the flood. Contact me by email discuss how you=
can help.

If there are enough people out there who care about this stuff, we can do t=
his.  You don't have to live in Houston.  You don't have to live on the Gul=
f Coast.  It's even OK if you don't live in Texas.


To donate online, go to http://www.hlctm.org/services.htm and click on "Don=
ate."



To contact me, send email to hcmjkeys at yahoo dot com.


Once we have something presentable, come visit.  And thanks very much for r=
eading this.



John Keys

Re: Keys resurfaces

[Tothwolf]

On Fri, 4 Sep 2015, William Donzelli wrote:

It seems to happen all the time with collectables (I must admit I have 
a loft room full, and I don't have anywhere to exhibit) but to me this 
needs PEOPLE and then a PLAN and lastly a Kick Starter project to get 
it exhibitable, if indeed any of it is exhibit able. I can't see any 
responses in a.f.c but if any one can let me know what the money is 
needed for and how its going to be spent then I could start considering 
donating...


Consider, however, that Keys and the Houston Computer Museum has been 
sort of a black hole for the past 15 years. I do not know if anyone has 
really seen any sort of exhibit.


https://www.youtube.com/watch?v=JWogDZ9weSs

If a museum did not materialize when he was 55 or 60, they probably are 
not going to materialize at 70 or 75.


And if the Houston Computer Museum is a proper museum, there will be a 
clause in the bylaws guiding the disposition of the artifacts to other 
501c3 entities.


Keys had a table at VCF SW 3.0 but I'm not sure if that really counts as 
an exhibit.


http://www.computerculture.org/events/vcfsw3/

Re: Keys resurfaces

[Tothwolf]

On Fri, 4 Sep 2015, jwsmobile wrote:

On 9/4/2015 12:54 PM, Tothwolf wrote:

On Fri, 4 Sep 2015, William Donzelli wrote:

It seems to happen all the time with collectables (I must admit I 
have a loft room full, and I don't have anywhere to exhibit) but to 
me this needs PEOPLE and then a PLAN and lastly a Kick Starter 
project to get it exhibitable, if indeed any of it is exhibit able. I 
can't see any responses in a.f.c but if any one can let me know what 
the money is needed for and how its going to be spent then I could 
start considering donating...


Consider, however, that Keys and the Houston Computer Museum has been 
sort of a black hole for the past 15 years. I do not know if anyone 
has really seen any sort of exhibit.


https://www.youtube.com/watch?v=JWogDZ9weSs

If a museum did not materialize when he was 55 or 60, they probably 
are not going to materialize at 70 or 75.


And if the Houston Computer Museum is a proper museum, there will be a 
clause in the bylaws guiding the disposition of the artifacts to other 
501c3 entities.


Keys had a table at VCF SW 3.0 but I'm not sure if that really counts 
as an exhibit.


http://www.computerculture.org/events/vcfsw3/


He got a big collection of SDS systems which I helped store the tape 
drives and printers for.  Al was supposed to get the media, but it never 
got to me to get to Al and back.


Anyone happen to notice this?

Acquisition Policy for the Houston Computer Museum
http://www.hlctm.org/serv02.htm

[...]

"The item should be of museum quality (exceptions will be made for certain 
items). Primary consideration will be given to the museum's ability to 
provide proper care and storage for any artifact or works of art. No item 
should be considered for acquisition if its physical condition exceeds the 
museum's financial ability to provide for its care and preservation."


"The museum must be able to provide proper storage for any acquisition 
under consideration."


[...]

"The museum acknowledges its responsibility to ascertain that items 
offered, whether by purchase, exchange, gift, or bequest, are not stolen, 
wrongfully converted, or acquired under false pretences. All such items 
will be declined."


"If the museum should discover that it has inadvertently acquired an item 
that is proven to have been obtained in violation of the above statement, 
the museum shall seek to return the item to its legal owner or shall seek 
to determine, through outside recognized and competent authorities, the 
proper means of disposition."


[...]

With the storage situation, does this mean he is in violation of his 
501(c)(3) requirements?


What does this mean for that vanload of gear Keys took out from under me 
via false pretenses?

Re: Possible road trip....Illnois, Canada, Maine and back

[Tothwolf]

On Fri, 4 Sep 2015, William Donzelli wrote:


Yes. ALL the ducks.

Several of us have been bounced at the border for trying to bring in 
larger machines. Basically, if it is something that is not a laptop or 
PeeCee or normal consumer electronics, expect trouble. It is not 1998 
anymore.


Do "Made in USA" markings still suffice when transporting from Canada to 
the USA?

Re: Electronic devices and borders - Re: Possible road trip....Illnois, Canada, Maine and back

[Tothwolf]

On Fri, 4 Sep 2015, Toby Thain wrote:

On 2015-09-04 5:20 PM, Jason T wrote:


read my email on my phone


I hope everyone saw that and understands what it means.

Borders have changed. Any data you take across them is fair game.


Indeed they have. ...and things continue to change:

https://en.wikipedia.org/wiki/Riley_v._California

https://www.techdirt.com/articles/20150818/16495632000/doj-dismisses-case-after-court-explains-that-feds-cant-just-grab-someones-laptop-border.shtml

https://www.techdirt.com/articles/20150511/08053430957/court-rejects-questionable-border-search-laptop-saying-computers-are-not-just-containers.shtml

RE: IBM 1620

[Tothwolf]

On Sun, 30 Aug 2015, Dave G4UGM wrote:

On Sat, 29 Aug 2015, Tothwolf wrote:

IBM had special machines to position and thread them. 
http://ibm-1401.info/IBMCoreArraysIEEEMagnetics1969.pdf


Thanks for posting that. Very interesting. Looking at it, the machines are
extremely complex, but I am sure they could be reproduced, albeit at a
probably prohibitive cost...
.. I have marked for later reading...


Something else I forgot to mention, is that on page 8 in that pdf file, 
they mention initially using 60/40 tin-lead alloy solder for the enamel 
wire to the core plane terminals. On page 9, they describe switching to 
20/80 tin-lead so the solder would dissolve less copper from the enamel 
wire.


If repair of the core memory in CHM's IBM 1620 is ever attempted, I think 
either low-tin solder alloy with 1-2% added copper or possibly a more 
modern indium-lead solder alloy would probably be the best choice for the 
enamel wire to terminal connections since that would greatly reduce the 
likelihood of any future wire breakage.

Re: IBM 1620

[Tothwolf]

On Sun, 30 Aug 2015, Paul Koning wrote:

On Aug 30, 2015, at 1:55 PM, Chuck Guzis ccl...@sydex.com wrote:
On 08/30/2015 09:47 AM, Tothwolf wrote:

If repair of the core memory in CHM's IBM 1620 is ever attempted, I 
think either low-tin solder alloy with 1-2% added copper or possibly a 
more modern indium-lead solder alloy would probably be the best choice 
for the enamel wire to terminal connections since that would greatly 
reduce the likelihood of any future wire breakage.


Wouldn't solderless bonding/welding be a better alternative?


That's what the IBM IEEE article mentions.

I'm still a bit puzzled by the dissolving of copper wire by conventional 
solder.  The wire used in core memories is thin, but not outrageously so 
by the standards of, say, Litz wire, and that is soldered routinely.


See the other paper I mentioned earlier in the thread: 
https://app.aws.org/wj/supplement/WJ_1975_10_s370.pdf


On page 5, they describe 0.0031 40 AWG magnet wire being reduced to 0.002 
after soldering with 60/40 tin-lead solder. That 0.0011 reduction is 
basically 1/3 of the diameter of the wire. This explains the failures of 
the enamel wires in CHM's IBM 1620.


Copper erosion from tin is something I'd never really given a lot of 
thought to, but it will certainly be something I keep in mind from now on.

Re: De-yellowing results

[Tothwolf]

On Sun, 30 Aug 2015, Chuck Guzis wrote:

On 08/30/2015 11:08 AM, Jules Richardson wrote:

On 08/28/2015 12:08 PM, Evan Koblentz wrote:

We're thinking about building that kind of deyellowing station in 
the MARCH warehouse.


Hmm, single UV lamp, couple of stepper motors and a couple of circular 
tracks, one set at right angles to the other - plus a few misc. bits 
and pieces? ;-)


I'd wager that a couple of T8 germicidal lamps (UVC) would do the trick 
pretty quickly, but they're pricey, unless you have a friend who runs a 
slaughterhouse or sewage treatment plant.  Can be ordered through Home 
Depot.


Wrong type of UV. You are mostly getting long wave UVA outdoors, so 
blacklight lamps would seem to be the correct (and MUCH safer) choice. 
When I looked at 24 T8 bi-pin blacklight lamps, they were going for about 
USD $10 per lamp.


UVC germicidal lamps would also require an enclosure to protect the user 
from exposure to short wave UV. This isn't as necessary with long wave UVA 
(unless someone was going to be around it for long periods of time on a 
regular basis).

Re: Sales of unearthed Atari games total more than $100,000

[Tothwolf]

On Sun, 30 Aug 2015, drlegendre . wrote:

On Sun, Aug 30, 2015 at 1:41 PM, Ali cct...@fahimi.net wrote:

How might a collector discern a landfill E.T. cart from any other 
E.T. cat that some snarky guy buried in the clay of his back forty?


Not that I am expert or anything but my understanding is that the ET 
cart is extremely rare to begin with. In fact the landfill collection 
is the largest supply of the cart to be injected into the market.


A quick search of eBay would correct your 'understanding'. There are 
dozens of copies for sale, many with boxes and manuals. They start at 
about $5.00.


The game is very common, and generally considered worthless. It's a 
joke, possibly the worst video game ever made - up there with Superman 
64 for N64.


When I used to buy Atari stuff at resale shops to build my own collection 
(back in the early to mid 1990s when people were practically giving away 
2600 stuff), ET seemed to be pretty common. It wasn't nearly as common as 
Pac-Man or Pitfall! or a pack-in game like Combat, but I saw them 
frequently. I gave/traded away quite a few copies of ET but kept at least 
one.

Re: IBM 1620

[Tothwolf]

On Sun, 30 Aug 2015, Chuck Guzis wrote:

On 08/30/2015 09:47 AM, Tothwolf wrote:


If repair of the core memory in CHM's IBM 1620 is ever attempted, I
think either low-tin solder alloy with 1-2% added copper or possibly
a more modern indium-lead solder alloy would probably be the best
choice for the enamel wire to terminal connections since that would
greatly reduce the likelihood of any future wire breakage.


Wouldn't solderless bonding/welding be a better alternative?


Yes, if the terminals had been designed for that. The terminals on these 
would have been designed for soldering, so unless you wanted to replace 
all the existing terminals, it would probably be best to stick to 
soldering. Either a low-tin + copper or non-tin solder really should solve 
the problem anyway.

Re: IBM 1620

[Tothwolf]

On Sun, 30 Aug 2015, ben wrote:

On 8/30/2015 6:32 PM, Tothwolf wrote:

On page 5, they describe 0.0031 40 AWG magnet wire being reduced to 
0.002 after soldering with 60/40 tin-lead solder. That 0.0011 
reduction is basically 1/3 of the diameter of the wire. This explains 
the failures of the enamel wires in CHM's IBM 1620.


Copper erosion from tin is something I'd never really given a lot of 
thought to, but it will certainly be something I keep in mind from now 
on.


But is that the case? Would not heat induced failure be the real case 
here as I suspect that a amp or two of current is flowing that now very 
thin thread of wire? Digging though the doc's and a little calculation 
clear this up.


My guess is that over time the thinned wires broke due to a combination of 
vibration and thermal fatigue. Vibration while transporting the system to 
CHM may well have been what ultimately caused them to break.

Re: De-yellowing results

[Tothwolf]

On Sun, 30 Aug 2015, Chuck Guzis wrote:

On 08/30/2015 05:55 PM, Tothwolf wrote:

Wrong type of UV. You are mostly getting long wave UVA outdoors, so 
blacklight lamps would seem to be the correct (and MUCH safer) choice. 
When I looked at 24 T8 bi-pin blacklight lamps, they were going for 
about USD $10 per lamp.


Oh, but there's that aitch-nu thing--I suspect that the UVC lamps would 
do the job very quickly.  I recall that someone tried the de-yellowing 
process with UV LEDs and got nowhere fast.  So probably UVB at a 
minimum.


Maybe...maybe not. I do know from experience that short wave UVC from 
germicidal lamps can photodegrade certain plastics, PVC in particular. UVC 
germicidal lamps can also cause serious eye damage in very short order. 
Even the really small UVC lamps used in an EPROM eraser are hazardous, 
which is why they have interlock switches that disable the lamps when 
open.


You are going to get a _lot_ more UVA exposure than UVB outdoors, but who 
knows. You aren't going to get much UVC outdoors though.


A typical T1-3/4 UV led doesn't put out anywhere near the energy that a 
bi-pin/fluorescent lamp does, so unless you had a large array of high 
output UV leds, I really wouldn't expect all that much from them.

Re: IBM 1620

[Tothwolf]

On Sat, 29 Aug 2015, Paul Koning wrote:

On Aug 29, 2015, at 12:36 AM, Lyle Bickley lbick...@bickleywest.com wrote:

I was not on the Team that did the memory analysis and the ultimate 
modern replacement memory. However, when I joined the Team, I asked 
similar questions and was told that the core memory was literally 
falling apart and was not repairable.


I sure have a hard time fathoming any of this.

Quite apart from the obvious one of building a pin-compatible modern 
memory, another answer comes to mind.  If a core plane has come apart, 
the cores could be recovered and restrung.  That requires patience and 
dexterity, but it should be doable.  It also requires a device to hold 
the cores correctly for threading; something like that could easily be 
made in a a 3d printer.


Those particular cores are quite small and I'm not sure a 3d printer would 
be able to print a jig with the tolerances required. IBM had special 
machines to position and thread them. 
http://ibm-1401.info/IBMCoreArraysIEEEMagnetics1969.pdf


I can certainly understand why repair wasn't initially attempted, however 
that doesn't mean it is impossible. Given the rarity of the system, 
welding new stubs of wire to the original enamel wire or completely 
rebuilding the core planes with all new wire might still well be a 
worthwhile project at some point in the future. It might even be possible 
to keep most of the cores in position and rethread just one portion (X, Y, 
sense/inhibit) at a time.


Another plus is that because of the way the wires are threaded, it is 
unlikely that any of the cores have been lost, even if a large number of 
wires have broken at the terminals.

Re: IBM 1620

[Tothwolf]

On Thu, 27 Aug 2015, Lyle Bickley wrote:

The IBM 1620 at the CHM is a running computer. There were two teams that 
worked on the 1620 at the CHM. The first Team got it running. 
Unfortunately, IBM used the wrong kind of solder on the core memory and 
so the wires of the core memory literally dissolved.


With all the different solder alloys I work with regularly, I have to 
ask...what type of solder caused that sort of damage? Was it the alloy 
itself, or did IBM use a flux which was too active and then failed to 
clean away all the residue? If they used a rosin-based flux, was it due to 
the specific activator used in the flux?

Re: IBM 1620

[Tothwolf]

On Fri, 28 Aug 2015, Lyle Bickley wrote:

On Fri, 28 Aug 2015 20:31:16 -0500 (CDT) Tothwolf wrote:

I think I've answered my own question today while looking at a 
datasheet for another type of solder. My guess is that the solder they 
used did not contain any copper, and the tin in the solder IBM used 
dissolved small amounts of the already very tiny copper wires, creating 
a weak point where the wires were soldered to the terminals.


Lyle, was there any discussion of possibly laser welding replacement 
stubs of wire before the breaks that could then be re-soldered to the 
terminals? That would seem to be a viable repair option, although it 
would require special equipment.


I was not on the Team that did the memory analysis and the ultimate 
modern replacement memory. However, when I joined the Team, I asked 
similar questions and was told that the core memory was literally 
falling apart and was not repairable.


So the core mats were more or less dangling? Still, I would think they 
would be repairable, but it would be a major undertaking since there would 
probably be 1000s of tiny stubs of wire to weld in (every single 
connection, basically). All of those enamel wire terminations would then 
also need to be soldered to the terminals with either a low-tin or copper 
containing alloy of solder too.


I also can't help but wonder what other systems which use core memory 
might suffer from this type of failure as they continue to age.


Any chance someone on the team took some photos of the core memory? I 
didn't see any on CHM's IBM 1620 webpage. 
http://www.computerhistory.org/projects/ibm_1620/ibm1620/


For those interested, here is a paper Google turned up which explains the 
problem:


Lead Alloys for High Temperature Soldering of Magnet Wire
https://app.aws.org/wj/supplement/WJ_1975_10_s370.pdf

Re: IBM 1620

[Tothwolf]

On Fri, 28 Aug 2015, Chuck Guzis wrote:

On 08/28/2015 07:42 AM, Tothwolf wrote:

With all the different solder alloys I work with regularly, I have to 
ask...what type of solder caused that sort of damage? Was it the alloy 
itself, or did IBM use a flux which was too active and then failed to 
clean away all the residue? If they used a rosin-based flux, was it due 
to the specific activator used in the flux?


That's actually a little puzzling.  1401 core frames have survived well 
(got one in my desk drawer).  You'd expect that the same process would 
be used for equipment that's pretty close to contemporary.


I think I've answered my own question today while looking at a datasheet 
for another type of solder. My guess is that the solder they used did not 
contain any copper, and the tin in the solder IBM used dissolved small 
amounts of the already very tiny copper wires, creating a weak point where 
the wires were soldered to the terminals.


Lyle, was there any discussion of possibly laser welding replacement stubs 
of wire before the breaks that could then be re-soldered to the terminals? 
That would seem to be a viable repair option, although it would require 
special equipment.

RE: De-yellowing results

[Tothwolf]

On Fri, 28 Aug 2015, Ali wrote:

Ah! That explains my lack of results. I soaked the keys for five or six 
hours. They got clean, but didn't change color very much. Sounds like I 
pulled them out too soon. Several days, you say?


Has anyone tried a glass/plexi-glass bath w/ UV lights? It might get 
expensive if you want UV lights that are dimmable (to control strength) 
but UV lights and ballasts are not that expensive. A simple timer and 
maybe a reflective surface on the enclosure and you are good to go. Then 
real experiments can be done by varying exposure time and concentration 
of the solution to see if there is a happy medium. Problem is you need 
someone with lots of yellowed parts that they don't mind experimenting 
on/ruining in the process.


Glass blocks UV light. This is why EPROMS were made with quartz windows 
even though glass would have been much cheaper. Regular acrylic plastic 
will block UV as well, but special types are available that allow 
transmission of UV (such as for sun room roof panels and tanning beds).


Keep in mind also that short wave UV-C (such as a germicidal lamp) is 
dangerous to work around, which is why devices such as EPROM erasers 
generally have a mechanical interlock to disable the lamp when open. UV-A 
(blacklight) is much safer, and would probably give about the same results 
as having something out in the sun (UV-C is blocked by the atmosphere 
while UV-A isn't).

Re: In Realtime: Saving 25,000 Manuals — August 15, 2015

[Tothwolf]

On Mon, 24 Aug 2015, Jason Scott wrote:

On Mon, Aug 24, 2015 at 2:16 PM, Dave Woyciesjes woycies...@sbcglobal.net 
wrote:

On 08/21/2015 08:08 PM, Liam Proven wrote:

On 15 August 2015 at 13:03, Liam Proven lpro...@gmail.com wrote:


http://ascii.textfiles.com/archives/4683

Apologies if this is old news...


Some pictures, from sun-rescue:

https://www.flickr.com/photos/textfiles/albums/72157657277241785/page1


I'm curious, what percentage of thier stock was saved?


If you go by unique manuals, 95-99%.
If you go by total number of manuals, including duplicates, probably 
25-30%.


Possibly more. When I spoke to Becky last Thursday, she mentioned several 
local people wanted to come pick up whatever was left. I have no idea if 
that has actually happened though.

Re: HP 5480A, or, obscure HP instruments

[Tothwolf]

On Mon, 24 Aug 2015, Peter Brown wrote:

Was there any resolution to the original request for HP5480A service 
information?


I have fiches for this instrument as follows

1. 5480A - Signal Analyzer Operating manual Part 1 - 05480-90014(fiche) - 2 
fiches, 60 pages per fiche
2. 5480A/B - Signal Analyzer system vol 1System service manual - 
05480-90015(fiche) 7 fiches, 60 pages per fiche
3. 5480A/B - Signal Analyzer system operating and service manual - 
05480-90025(fiche) 5 fiches, 60 pages per fiche
4. 5480A/B - Signal Analyzer with 5485A, 5486AB, 5487A, 5488A service Volume 2, 
3 and 4 - 05480-90016(fiche) 8 fiches, 60 pages per fiche

.. but no way of printing them out

[On topic part]

Is there a cost effective / group accessible method for making manuals 
that were originally supplied on fiche available to the group?


Possibly. I'll email you some contact information off-list.

Re: De-yellowing

[Tothwolf]

On Sat, 22 Aug 2015, Jules Richardson wrote:

On 08/21/2015 05:28 PM, Evan Koblentz wrote:

So, how does one de-yellow something?  I have a VT-100 and some other 
gear that could use that process.


Google for Retr0brite.


I've never tried the stuff - but is it a permanent fix, or does the 
yellowing gradually come back?


It almost always seems to comes back to some extent. De-yellowing 
treatments only work on the outermost surface of the plastic, and there 
are still plenty of free bromides just under the treated surface which 
will migrate outward. The re-yellowing (which may or may not be much less 
than the original yellowing) also occurs much faster than the original 
yellowing. Unless you can somehow eliminate all the free bromides from the 
plastic, de-yellowing treatments such as Retr0brite are just a temporary 
cosmetic fix.

Re: HP 5480A, or, obscure HP instruments / was Re: More on manuals plus rescue

[Tothwolf]

On Thu, 20 Aug 2015, Jay Jaeger wrote:

On 8/20/2015 7:11 AM, tony duell wrote:


They reuse numbers for what I call marketing numbers.  For example, 
with a LaserJet 8150dn, the 8150 is a marketing number and not the 
actual HP product number, which was C4267A.  As far as I know they've 
never actually reused a product number.


I know that's no consolation when you search for HP 5480 for that 
product, and get printers or supplies with that marketing number 
instead.


I get irritated when I search for HP9100 (meaning the first desktop 
scientific calculator thing) and get hits for some modern-ish 
printer/scanner. Admittedly that is a 9100C (the calculators were 9100A 
and 9100B), but...


At least, under Google and eBay, one can add exclusionary terms:

hp 9100 -printer -scanner

Seems to do pretty well under Google.  Under eBay I had to add a lot 
more exclusions, and ran out of room.


With eBay, you can also group them: -(printer,scanner)

It only helps a little though and when eBay eliminated wildcard matching 
awhile back, they also reduced the maximum query length. What I /really/ 
don't like about eBay's current search system, is how it substitutes 
keywords internally. If I search for Compaq, I don't want results for 
HP, and likewise if I search for HP, I don't want results for 
Compaq...

Re: De-yellowing

[Tothwolf]

On Sat, 22 Aug 2015, Jules Richardson wrote:

On 08/22/2015 07:48 AM, Tothwolf wrote:

On Sat, 22 Aug 2015, Jules Richardson wrote:

On 08/21/2015 05:28 PM, Evan Koblentz wrote:


Google for Retr0brite.


I've never tried the stuff - but is it a permanent fix, or does the 
yellowing gradually come back?


It almost always seems to comes back to some extent. De-yellowing 
treatments only work on the outermost surface of the plastic, and there 
are still plenty of free bromides just under the treated surface which 
will migrate outward. The re-yellowing (which may or may not be much 
less than the original yellowing) also occurs much faster than the 
original yellowing. Unless you can somehow eliminate all the free 
bromides from the plastic, de-yellowing treatments such as Retr0brite 
are just a temporary cosmetic fix.


I thought that might be the case, but thought I might be mistaken given 
how many people seem to rave about how wonderful this stuff is.


It does give something a nice temporary cosmetic fix, but in most cases it 
just doesn't last. As little as a year later something can be completely 
yellow again. It probably has a lot to do with the specific amount of 
bromide and other stuff in the plastic.


Within a museum context, where showing original factory condition is 
probably a desirable thing, have there been any studies to ensure that 
retrobright (or other treatments) don't cause any damage to the plastics 
(e.g. making the surface less resistant to scratches, or the plastic 
more brittle, say)?


Long term UV exposure isn't exactly good for plastics, but I can't see 
lower concentrations of Hydrogen Peroxide doing any damage. Heavy UV 
exposure tends to make a lot of thermoplastics very brittle.


Personally I quite like the patina of a yellowed machine anyway - being 
able to see how it sat in a room, or where stickers used to be and such; 
it's a minor thing, but sometimes it does tell a little bit of a story. 
Maybe in 20 years if I ever sell any of my collection I might consider 
it, but for now they may as well stay yellow :)


I had my yellowed TRS-80 Model 100 out yesterday to finally remove its 
internal NiCd battery (I caught it just in time, there was a tiny amount 
of discoloration of the solder mask at one end, which is probably the 
copper trace tarnishing, but the solder mask was still firmly adhered to 
the copper). It would be nice if the machine weren't yellowed, but the 
yellowing doesn't stop me from using it.


My model 100 has mostly lived in a box since I bought it (keeps the dust 
out of the keyboard when I'm not tinkering with it) and it has a very even 
yellowing to the light colored plastic (I don't think it has worsened any 
since I got it). I just haven't been able to justify the time and the cost 
of the materials to retr0brite it since I know the yellowing would 
reoccur, even with it stored in a box.


Maybe someone will eventually come up with a way to bring those free 
bromides out to the surface where the Hydrogen Peroxide will take care of 
them.


I wouldn't think it would make much of a difference, but has anyone tried 
putting a plastic part under vacuum to see if that helps?

RE: De-yellowing

[Tothwolf]

On Sat, 22 Aug 2015, Dave G4UGM wrote:

On Sat, 22 Aug 2015, Pete Turnbull wrote:

On 22/08/2015 13:50, Tothwolf wrote:

On Sat, 22 Aug 2015, Dave G4UGM wrote:


All the techniques discussed so far involve using a bleach of some
kind and possibly UV light. Some use other materials so you have a
gell which makes it easier to apply.
From what I have read yellowing usually/often/always re-occurs..


Hydrogen Peroxide, not bleach.


Hydrogen peroxide *is* a bleach, as any chemist can tell you.  Never 
heard of peroxide blonde?


I should probably have said a peroxide based bleaching agent as most 
folks assume bleach means chlorine based bleach which is not what is 
being used here.
However there are several variations on this theme and several slightly 
different chemicals have been used as the bleach...


Exactly what I meant. Most will assume chlorine based bleach when someone 
mentions the term bleach.

Re: More on manuals plus rescue

[Tothwolf]

On Fri, 21 Aug 2015, geneb wrote:

On Fri, 21 Aug 2015, Evan Koblentz wrote:

On Wed, 19 Aug 2015, et...@757.org wrote:

Years ago I needed a HP service manual for a plotter I was trying to 
repair that I owned. HP of course wouldn't let me have it, so I had to 
buy a PDF copy from someone on eBay. I ended up removing the password 
and posting it on my website.


That's called stealing.


HP no longer had the manual in their archives so they couldn't provide it.

No it's not.  At *worst* you're voilating the copyright of someone elses 
copyright violation. COPYRIGHT INFRINGEMENT IS. NOT. THEFT.  This is not 
my opinion, it's decided case law by the Supreme Court.


Sigh. I'm just going to leave these here...

Release of copyright
http://www.ko4bb.com/getsimple/index.php?id=downloadfile=Tektronix/Tektronix_-_Miscelaneous/Tek_Copyright_Release.pdf

Tektronix Policy on Copying of Out-of-date Materials
http://www.tek.com/dl/Tektronix_Policy_on_Copying.pdf

To put this more back on the original subject, Manuals Plus also had 
explicit permission from both Tektronix and HP/Agilent/Keysight to 
actually duplicate/reprint their manuals. This is why some manuals were so 
expensive...they were copied as needed to fill an order, and according to 
Becky, it was a very labor intensive process. Jason will know exactly what 
I'm talking about here too, as he got their Master (Reprint) manuals.

Re: Vintage Software Copyright

[Tothwolf]

On Fri, 21 Aug 2015, Chuck Guzis wrote:

On 08/21/2015 10:11 AM, Rod Smallwood wrote:


Yes OK and very long  would be?


It varies by country.  In the case of the USA, 95 years from publication 
(for older works)  Other countries employ the author's life+x years 
(usually 50 or 70)--live to a ripe old age and your copyright can run 
for a very long time.


In the USA, the rule of thumb is that you're generally safe with works 
published before 1923, which, I imagine does not include much computer 
software.


...and works published before 1964 which were either not registered with 
the US copyright office or which did not have their copyrights renewed. 
Those require some research to determine their status.

Re: More on manuals plus rescue

[Tothwolf]

On Wed, 19 Aug 2015, Sean Caron wrote:

On Wed, Aug 19, 2015 at 7:50 PM, William Donzelli wdonze...@gmail.com wrote:

On Wed, 19 Aug 2015, Tothwolf wrote:

I have to disagree strongly with Will on this. There are quite a few 
PDF manual dealers who honestly deserve to go out of business. Those 
dealers tend to fall into two categories:


It does not matter. You can not scan ashes.


I guess if philistines want to pillage themselves, that is their sad 
perogative ... but if releasing the entirety of Manuals Plus to the 
public domain will break them, maybe they don't really have anything all 
that unique after all?


According to Becky at Manuals Plus, these companies that have taken to 
selling people scans of manuals, combined with all the other freely 
available online manuals played a large part in them shutting down.


Tektronix also issued a public statement giving permission for people to 
freely duplicate and distribute their older test equipment manuals not all 
that long ago, and that can't have helped either.


The way I look at it, the companies that took to selling people PDF copies 
of manuals they've collected and then tried to lock up have had it coming, 
and some of them have been due such a blow for a long time now.


I'm starting to look at this much like what happened with Netscape vs 
Microsoft Internet Explorer. Microsoft might have more or less killed off 
Netscape, but in releasing the source code which became Mozilla Firefox, 
they seriously damaged Microsoft's market share later.

Re: More on manuals plus rescue

[Tothwolf]

On Wed, 19 Aug 2015, William Donzelli wrote:

Are you serious? Jason is currently sweating his balls off trying to 
save at least a portion of a huge warehouse of unique documentation 
under an incredibly tight deadline.


Just for the record, the Manuals Plus hoard is not, in any way, a bunch 
of unique documentation. Test equipment docs are actually very common, 
and hoards of thousands of manuals are also fairly common.


I will try to elaborate on the subject later, but I have had one helluva 
day...(in a mostly good way)...


Actually, their collection was unique and contained a lot of material 
which others' libraries (either dead tree or digital) do not contain. This 
year, I purchased many one of a kind manuals from Manuals Plus for 
equipment ranging from the 1940s to 1980s that I've had sitting around for 
10-15+ years. No one else had those manuals, period.

Re: More on manuals plus rescue

[Tothwolf]

On Wed, 19 Aug 2015, Jason Scott wrote:

On Wed, 19 Aug 2015, William Donzelli wrote:

In closing, I might ask you to consider taking your sweet time getting 
this stuff online. There are still some manual dealers out there. Let 
them handle the decline of their business in whatever way they see fit. 
All of them know it is just a matter of time - probably five years or 
less. If you flood the net with the free scans, it might really fuck 
them up. I know some of them, and it is not unreasonable for me to 
think that they might get really annoyed by your efforts and burn their 
libraries just for spite.


That is a most interesting metric. I honestly hadn't considered that 
issue. The key, I think, will be communication with them to understand 
which manuals have sales going on, and which ones it would be 
advantageous to get online because they have long dropped into 
historical myths. Thank you for the advice. All of it.


I have to disagree strongly with Will on this. There are quite a few PDF 
manual dealers who honestly deserve to go out of business. Those 
dealers tend to fall into two categories:


First, the large number who have built their PDF libraries from collecting 
everything they can find online. Quite often they'll take the work of 
hobbyists and simply watermark / lock (encrypt) the PDF file then offer it 
for sale. Some of these dealers have websites, while others just try to 
hock their wares on eBay and other ecommerce platforms.


Second, those that threaten others when they find a PDF manual online 
which competes with their offerings. Some of them will file bogus DMCA 
takedowns even though they are not the copyright holder. Some of these 
dealers try to assert that because they scanned a manual (...or claim to 
have scanned it), that /they/ then hold the exclusive copyright to the PDF 
version of that manual.


Copyright just doesn't work like that though...the original copyright 
holder /still/ holds the copyright, no matter if someone scans it to a PDF 
or makes a xerox copy. Under US copyright law, they cannot even make a 
sweat of the brow argument as that is not an accepted legal argument 
under US copyright law.


17 U.S. Code § 103 - Subject matter of copyright: Compilations and 
derivative works


(b) The copyright in by the author of such work, as distinguished from 
the preexisting material employed in the work, and does not imply any 
exclusive right in the preexisting material. The copyright in such work is 
independent of, and does not affect or enlarge the scope, duration, 
ownership, or subsistence of, any copyright protection in the preexisting 
material.


https://www.law.cornell.edu/uscode/text/17/103

https://en.wikipedia.org/wiki/Derivative_work

https://en.wikipedia.org/wiki/Sweat_of_the_brow

Re: More on manuals plus rescue

[Tothwolf]

On Wed, 19 Aug 2015, William Donzelli wrote:

On Wed, 19 Aug 2015, Jason Scott wrote:

That is a most interesting metric. I honestly hadn't considered that 
issue. The key, I think, will be communication with them to understand 
which manuals have sales going on, and which ones it would be 
advantageous to get online because they have long dropped into 
historical myths. Thank you for the advice. All of it.


Yes, let the guys keep selling the higher demand documents - HP, Tek, 
Heathkit. Nearly all of those are super common anyway (and plus, you 
will run into problems posting Heath material). Focus on the weirder 
stuff - Krohn-Hite, Systron Donner, Clough-Brengle, Packard Instrument, 
Kay, and the like.


In fact, due to your time constraints, I would not bother with the HP, 
Tek, or Heathkit manuals at all. They can wait for the next hoard. They 
are low value targets eating up your limited resources.


I strongly disagree, but I won't repeat my reasoning here since I already 
wrote some of my reasons why in another reply.


As for Heathkit though... Danger, Will Robinson!

While I mentioned legal threats and false DMCA takedowns, I didn't name 
any names, however since Heathkit was brought up, and I did quite a bit of 
research a number of years ago regarding Heathkit manuals, I will name 
names.


Don Peterson, dba Data Professionals in Pleasanton, CA 
http://www.d8apro.com/ has for quite a number of years been sending 
questionable legal threats to anyone hosting Heathkit manuals (or selling 
copies of Heathkit manuals on eBay). Despite his Big Scary Letter, he 
does not appear to actually hold the copyright to /most/ Heathkit manuals 
(if he holds the copyright to any...more recent discussion seems to 
indicate that he was only sold the right to reproduce a selection of 
manuals). ...this of course hasn't stopped hobbyists, and large numbers of 
Heathkit manuals are hosted outside of the US, but quite a number of 
scanned manuals seem to have been (temporarily) lost thanks to his 
efforts.


I did just happen to notice this statement on http://www.d8apro.com/ so 
perhaps this mess is finally coming to an end?


Press Release April 2015 Data Professionals of Pleasanton California has 
been acquired by Heath Company and will focus on supporting vintage kits 
by providing parts, modification, and even 'Certified Pre-Owned' Heathkits 
for sale. Please watch our site for future developments.


Links:

Tubular Electronics: The Heathkit Copyright Question – More Silly Claims
http://tubularelectronics.com/?p=493

Old Electronics Kit Manuals Forced Offline Thanks To Copyright
https://www.techdirt.com/articles/20081215/0106043118.shtml

Heathkit Manuals: Should We Do Anything?
http://www.antiqueradios.com/forums/viewtopic.php?t=137298

Some jerk is squelching Heathkit schematics
http://www.eevblog.com/forum/chat/some-jerk-is-squelching-heathkit-schematics/

Heathkit Manual Copyright Challenged
http://forums.qrz.com/index.php?threads/heathkit-manual-copyright-challenged.373390/

Tubular Electronics: Vintage Books
http://tubularelectronics.com/?page_id=64

pestingers.net: Heathkit Manuals
http://www.pestingers.net/Pages_images/Heathkit/Heathkit_manuals.htm

Free manuals (was: Re: Manuals Plus preservation efforts update)

[Tothwolf]

I just heard from Becky this afternoon (I've been in regular contact with 
her) and she has said that anything left is now up for grabs. This is part 
of what she wrote me today:


If you know of anyone that wants to come here  help themselves over the 
next two days they are welcome. (Only if you weed the ones that want to 
meet us with 2x4's) Please have them contact me through this email. I do 
not particularly want them to just show up.


Becky's email address is: sa...@manualsplus.com

Given how busy she has been, I suspect email is much better than trying to 
reach her via phone.

Re: More on manuals plus rescue

[Tothwolf]

On Wed, 19 Aug 2015, Tothwolf wrote:

On Wed, 19 Aug 2015, William Donzelli wrote:

Yes, let the guys keep selling the higher demand documents - HP, Tek, 
Heathkit. Nearly all of those are super common anyway (and plus, you will 
run into problems posting Heath material). Focus on the weirder stuff - 
Krohn-Hite, Systron Donner, Clough-Brengle, Packard Instrument, Kay, and 
the like.


In fact, due to your time constraints, I would not bother with the HP, Tek, 
or Heathkit manuals at all. They can wait for the next hoard. They are low 
value targets eating up your limited resources.


I strongly disagree, but I won't repeat my reasoning here since I already 
wrote some of my reasons why in another reply.


As for Heathkit though... Danger, Will Robinson!

While I mentioned legal threats and false DMCA takedowns, I didn't name any 
names, however since Heathkit was brought up, and I did quite a bit of 
research a number of years ago regarding Heathkit manuals, I will name names.


Don Peterson, dba Data Professionals in Pleasanton, CA 
http://www.d8apro.com/ has for quite a number of years been sending 
questionable legal threats to anyone hosting Heathkit manuals (or selling 
copies of Heathkit manuals on eBay). Despite his Big Scary Letter, he does 
not appear to actually hold the copyright to /most/ Heathkit manuals (if he 
holds the copyright to any...more recent discussion seems to indicate that he 
was only sold the right to reproduce a selection of manuals). ...this of 
course hasn't stopped hobbyists, and large numbers of Heathkit manuals are 
hosted outside of the US, but quite a number of scanned manuals seem to have 
been (temporarily) lost thanks to his efforts.


I did just happen to notice this statement on http://www.d8apro.com/ so 
perhaps this mess is finally coming to an end?


Press Release April 2015 Data Professionals of Pleasanton California has 
been acquired by Heath Company and will focus on supporting vintage kits by 
providing parts, modification, and even 'Certified Pre-Owned' Heathkits for 
sale. Please watch our site for future developments.


I just found this on https://www.heathkit.com/heathkit-faq.html which 
confirms that despite his Big Scary Letters and legal threats, Don 
Peterson -did not- hold the copyrights to Heathkit manuals:


Q. I read on the Internet that someone else owns the copyrights to 
Heathkit manuals.


A. No, not correct. Heathkit has in the past given a contractual license 
to certain specific parties granting a limited right to reprint and sell 
paper copies of specific Heathkit manuals, to better serve valued Heathkit 
customers on those special occasions when you spill coffee on your 
original kit manual. Such reprinting agreements are designed to outsource 
Heathkit's reprinting operations to small companies who can provide 
replacement manuals cost-effectively but do not convey Heathkit's 
intellectual property, only permission to reprint authorized paper 
photocopies. All Heathkit copyrights remain with Heathkit.


Q. So Heath Company owns all Heathkit copyrights?

A. Yes. All Heathkit copyrights, and all Heathkit intellectual property, 
are property of Heath Company.

Re: More on manuals plus rescue

[Tothwolf]

On Tue, 18 Aug 2015, Shoppa, Tim wrote:

I certainly feel bitsavers is a good model, and although I'm physically 
not too far away from the stuff, I'm not sure I have much to offer other 
than disk space on a server for staging.


http://ascii.textfiles.com/archives/4695

(previous link: http://ascii.textfiles.com/archives/4683 )


The problem I've found with scans is that even at 600 dpi you lose detail 
necessary to make use of a lot of the material in these types of manuals 
(especially parts designations and values on schematics). It is amazing 
just how high the print quality is for many of these 1950s/60s/70s 
manuals.

Re: Unusual stuff inside computers

[Tothwolf]

On Sat, 1 Aug 2015, drlegendre . wrote:

On Sat, Aug 1, 2015 at 6:05 PM, Vlad Stamate vlad.stam...@gmail.com wrote:

I recently got a very nice HP 9816 with a 9121 drive unit from Earl 
Baugh (thanks Earl!). The computer worked fine but the primary drive of 
the 9121 refused to read the disk and made a continuous beating noise. 
After I cleaned it on the outside I opened it to see what is wrong with 
it. And I found this piece inside the drive itself: 
http://imgur.com/dlqOexX (floppy added for size comparison).


What is that item?

Looks like a piece of laced (p)leather-craft from a children's summer 
camp project..


Maybe it's a money clip?

Re: This Hobby Is Actually Useful!

[Tothwolf]

On Sat, 1 Aug 2015, Robert Jarratt wrote:

PS A related question. I struggled somewhat with the Weller Magnastat 
No. 8 tip, when trying to solder leads to the ground plane, I could not 
get the solder to stay molten very long. I was using lead-free solder, 
its melting point is much lower than the temperature which a No. 8 tip 
reaches. The iron is 50W. Clearly the ground plane was taking heat away, 
but is it a problem with the tip not being hot enough, the iron not 
powerful enough, or perhaps some operator error?


The Weller just didn't have enough thermal mass and a fast enough recovery 
for the task.


While some people prefer the digital readouts and pushbuttons on some of 
the newer soldering stations, I find older Hakko systems with a 
temperature control knob to be far easier to use. For a single sided or 
double sided plated-though board soldered with tin/lead alloy, I usually 
run a lower temperature somewhere around 600-650F. For a multi-layer board 
with large ground/power planes, or a board assembled with lead-free 
solder, 650-700F or slightly higher is often required.


I also suggest using traditional tin/lead alloy solder instead of the 
lead-free stuff. I only use lead-free where I absolutely have to and 
prefer to use a 63/37 tin/lead alloy even for repairing lead-free boards. 
Adding tin/lead solder to an existing lead-free joint before desoldering 
will also lower the melting temperature and help with the desoldering 
process. It usually isn't advisable to mix tin/lead solder with lead-free 
solder unless you are going to remove it though as some lead-free alloys 
do not mix well with traditional tin/lead.


When installing new components on a board where you are soldering to areas 
with a large thermal mass such as a ground or power plane, you might also 
want to consider using supplemental flux, such as a flux pen (even with 
through-hole components). The extra flux will help pre-clean the pads and 
component leads and will allow the solder to wet quicker. A more active RA 
flux can also help, however if you are working with a multi-layer board 
with internal ground/power planes (4 layers or more), a no-clean, 
low-solids rosin, or non-rosin flux might be required since some of those 
boards can wick a traditional RA or RMA rosin-based flux between the 
layers which will leave permanent dark spots inside the board.

Re: Unusual stuff inside computers

[Tothwolf]

On Sat, 1 Aug 2015, Vlad Stamate wrote:


Hi,

I recently got a very nice HP 9816 with a 9121 drive unit from Earl 
Baugh (thanks Earl!). The computer worked fine but the primary drive of 
the 9121 refused to read the disk and made a continuous beating noise. 
After I cleaned it on the outside I opened it to see what is wrong with 
it. And I found this piece inside the drive itself: 
http://imgur.com/dlqOexX (floppy added for size comparison).


After carefully removing it, the drive actually worked like a charm and 
I was able to boot from it. I was pleasantly impressed that the drive 
head has not been damaged bumping in the leather piece all the time. I 
am not sure how that got there, I assume a child pushed it in by 
mistake? I am not sure what it is either, the leather triangles sewn 
together by hand it seem.


What other strange pieces did you find when you opened up classic 
computers?


I once removed several ~1/2 diameter magnets from inside the 3.5 floppy 
drive of a tower-style IBM PS/2. They had apparently placed there by a 
disgruntled employee before he quick-formatted the hard drive. 
Fortunately, the magnets didn't seem to harm the boot disk I attempted to 
insert, but just jammed the drive.

Re: Reforming capacitors (technical description, not politics)

[Tothwolf]

On Wed, 29 Jul 2015, drlegendre . wrote:

On Wed, Jul 29, 2015 at 5:19 PM, Fred Cisin ci...@xenosoft.com wrote:

On Wed, 29 Jul 2015, drlegendre . wrote:

Incidentally, what exactly differentiates a computer-grade cap from 
any other alum. electrolytic?


Maybe computer-grade don't need gold-plated oxygen-free leads?


I get the jab you're taking at latter-day Audiophool idiocy, but you 
won't find any gold-plated OFC business in any of the vintage gear I 
typically work with.


But as far as gold plating goes, gold is a good conductor, it solders 
very well, it doesn't tarnish and its ductility promotes solid 
connections on screw terminals - it's really these characteristics that 
make it somewhat desirable in certain applications. So it's not so much 
that gold sounds better, it's that it allows one to make connections 
that work better. But it does tend to wear quickly.


While I don't want to go /too/ OT here, I do want to clear up one common 
misconception regarding gold plating. It isn't that gold itself wets 
easily when soldering...the tin content of the solder actually dissolves 
the gold and the solder bonds to the underlying metal surface.


This can also lead to gold embrittlement of the solder joint, and while it 
generally wasn't as big of an issue with larger through-hole solder joints 
(such as with older semiconductors which had gold plated leads), it did 
become a major issue for SMD boards with gold plated pads, and especially 
with BGA components.


This is why in high reliability applications, industry practice has been 
to pre-tin gold plated surfaces which are to be soldered, using a two step 
solder bath. The first being more sacrificial which will collect much of 
the gold, and a second to catch anything which might still be left.

Re: H960 blank panel clips

[Tothwolf]

On Tue, 28 Jul 2015, Pete Turnbull wrote:

On 27/07/2015 23:13, Tothwolf wrote:

On Mon, 27 Jul 2015, John Wilson wrote:

The only thing here is, it's a *terrible* design.  Those damn nubs 
snap off so easily (I'm sure decades of outgassing haven't helped), 
even when you're expecting it and being super careful.


Yes, even in the late 70s i recall them being considered fragile.

Are the original parts made of nylon? If so, that might explain the 
tendency for them to break. Nylon 6/6 is hygroscopic, and over a long 
period of time, it could very well be swelling up just enough so the 
bulb portions are more likely to break off.


No, they're ABS - at least mine are, I just tested a few.  I don't know 
what grade, though, and perhaps something more flexible and forgiving - 
a different grade of ABS, semi-rigid PVC, or nylon would be better.


My suggestion, however, would be to incorporate a vertical slit in the 
ball and a couple of millimeters of the stem, so they're a less tight 
and less critical fit.  Might help, especially with a less brittle 
plastic.


If they are made of ABS and the ball isn't critical, why not mill or drill 
out a small bit of the broken stem and solvent weld in some round ABS 
stock to make a new stem? Methylene chloride (dichloromethane) works 
extremely well for ABS (methyl ethyl ketone in my experience does not work 
very well with ABS). I've been using Plast-I-Weld (Flex-I-File) but in the 
past I've also used Tenax 7R and Proweld (Ambroid), however Tenax 7R and 
Proweld have both since been discontinued.


Another option worth considering is polyacetal / polyoxymethylene 
(Delrin). It is tough, stable and inexpensive (but not as inexpensive as 
ABS). PVC cold flows under pressure and Nylon absorbs moisture and expands 
over time, so neither of those are all that great for this sort of 
application.

Re: Chromatics on ebay

[Tothwolf]

On Fri, 24 Jul 2015, William Donzelli wrote:

Within the last year or so, eBay removed the ability to report a 
non-selling seller. The only way to report a seller for this now (so 
they get a strike on their account) is to pick up the phone and call 
eBay. You have to ask (demand) to speak to someone in Trust and 
Safety and you also have to be prepared to spend about an hour or so 
on hold.


I do not know which Ebay you are calling, but the one that I call about 
once a month is much faster. I am never on hold for more than four 
minutes or so at most. If I am calling about a trust or safety issue, 
the hold time is generally much less.


Sounds like you are doing much better than me. eBay and Paypal use an 
outsourced call center company called ePerformax out of Cebu City, 
Philippines. While I can get a first level rep on the phone right away, 
actually getting them to transfer the call to eBay's actual Trust and 
Safety group in the US can be an absolute nightmare. Apparently, 
ePerformax's employees don't want to transfer a caller because it results 
in them getting a low score for the call. This is also why they'll tell 
you there are no managers, and if you demand one, you get Bob, Joe, Sue, 
or Elvis in the cube next door.


I last contacted eBay about 3 months ago when I had a seller pull a 
bait-and-switch when a tool I bid on sold for the opening bid amount. My 
wait time then was pretty consistent with my prior calls to them over the 
last 3 to 4 years (about a one hour call). That said, back before eBay 
outsourced their call center and closed the main ones in California and 
Utah, reaching an actual employee of eBay had been pretty easy.

Re: Chromatics on ebay

[Tothwolf]

On Fri, 24 Jul 2015, William Donzelli wrote:


Sounds like you are doing much better than me.


Power Seller Master Race.


Pfft...Nintendo forever! ;P

Just a former Power Seller here...and all I got was this lousy mug and 
certificate.

Re: Chromatics on ebay

[Tothwolf]

On Thu, 23 Jul 2015, William Donzelli wrote:


That's just seller's remorse.

It's obviously up to you, but I'd have strongly considered disputing it 
with eBay as a seller refusing to honor the auction results is every 
bit as bad (or even worse) than a buyer refusing to honor the auction 
result.


I agree. Report him.

Basic Ebay auctions are extremely easy to do - any idiot can do it.

He had six days while he could review and make sure everything was OK, 
and revise the listing if and error was spotted.


Within the last year or so, eBay removed the ability to report a 
non-selling seller. The only way to report a seller for this now (so 
they get a strike on their account) is to pick up the phone and call 
eBay. You have to ask (demand) to speak to someone in Trust and Safety 
and you also have to be prepared to spend about an hour or so on hold.

Re: PDP 11 gear finally moved

[Tothwolf]

On Wed, 22 Jul 2015, Chuck Guzis wrote:

On 07/22/2015 10:09 PM, Tothwolf wrote:

One example I can give are some Pentium P55C architecture (Socket 7) 
systems which I've been running with minimal downtime for ~15 years. 
The original power supplies with their original (and relatively low 
quality) capacitors lasted about 15 to 17 years (I think the 
manufacture date code stamped on the oldest one was 1998) before the 
systems began to develop stability issues, requiring me to rebuild the 
power supplies with new capacitors. I fully expect that the 
replacements would last even longer than 20 years, however I rather 
doubt I'll be running those computers by then.


Does anyone have much experience with the so-called solid electrolyte 
electrolytics?  Fvor replacing vintage caps, they're probably not a 
viable choice as they're mostly SMT, but just wondering...


I believe there are a few webpages out there written by people who have 
tried it. From what I remember reading about them years ago, they had no 
success when they tried to use them as replacements in switch mode power 
supplies (no surprise, since the solid polymer parts they attempted to use 
had way to low of ripple current rating for that application) but had 
better results with certain PC motherboards.


I use solid polymers as replacements in some applications, and as they 
continue to decrease in cost, I've been considering using them more for 
replacement of aging SMD aluminum electrolytics. One application where I 
particularly like solid polymers is for replacement of the vcore regulator 
filter capacitors on Pentium 4 industrial single board computers (yes, the 
P4 is still /widely/ used and extremely common in that market, although it 
is slowly being replaced by the Core Duo). The original aluminum 
electrolytics in that application are usually 6.3V rated parts while the 
solid polymer replacements are 2.5V or 4V (vcore is under 2V).


In addition to long term stability, another major benefit to solid 
polymers is that unlike aluminum electrolytics and solid tantalums, solid 
aluminum polymers they can be used at their full rated voltage with no ill 
effects. The only real downside that I know of for a solid polymer is that 
they have an incredibly low ESR (less than 0.01 ohm), which can actually 
upset older circuit designs which were not designed for capacitors with 
such a low ESR.

RE: PDP 11 gear finally moved

[Tothwolf]

On Wed, 22 Jul 2015, tony duell wrote:

On Wed, 22 Jul 2015, Noel Chiappa wrote:

I am way out of my knowledge range in this discussion, but here's 
something I wanted to ask about: how do you reconcile this observation 
(assertion?) with the observations from several people (e.g. the PDP-1 
people) that they _have_ measured the electrolytics in their power 
supplies, and despite being N decades old (where N ~= 5), they are 
_still_ within specs? If the very nature of electrolytics mandates that 
they degrade, how are these still meeting specs?


Well, at least 2 possibilities...

Firstly, the tolerance of the capacitance of an electrolytic capacitor 
is very wide -- -20% to +80% is not uncommon. So it's quite possible 
they started off at the top end of that range, have deteriorated over 
the years, and are still within spec. Of course nobody can prove that 
(unless there are records of the values meaured 50 years ago) and nobody 
really knows how they will continue to change (if indeed they do).


Secondly, I have no idea what was measured. The capacitance value is not 
the whole story by any means. In fact the most important thing most of 
the time is ESR (Effective Series Resistance) which increases as the 
electrolyte dries up. The ESR of these components could well still be OK 
after 50 years, but again nobody knows what it was when they were new.


That said, I keep on with the comment that the important thing is 'does 
the circuit behave as required', If so, then the capacitor is almost by 
definition OK in that circuit.


From what I remember from an earlier discussion about that PDP-1, after 
reforming, those large capacitors were leak tested at or slightly above 
their rated voltage.


As for meeting spec, unless DEC documented what their original design 
criteria was, there really is no way to know with 100% certainty. The only 
thing we could know today is if the capacitor passes industry standard 
tests and if the power supply those capacitors are a part of functions 
correctly when fully loaded.

RE: PDP 11 gear finally moved

[Tothwolf]

On Wed, 22 Jul 2015, tony duell wrote:

I think he did answer it. If the unit is operating correctly then the 
capacitors must be sufficiently good at that time for that unit.


Now, whether they will go on working is something that is very hard to 
tell. But that applies to every other component in the unit. An IC might 
work find now and suffer bond-out wire failure later on the same day.


Going purely from the historical data, failures of most semiconductors are 
/far/ less frequent than an aluminum electrolytic capacitor (except for a 
handful of certain TTL logic, which has been discussed previously here on 
classiccmp and elsewhere).


Just like the NiCd and SLA batteries I mentioned, aluminum electrolytic 
capacitors by their very electrochemical nature degrade as they age and 
as they are used. You cannot claim that a 20-30 year aluminum 
electrolytic


Semiconductors also degrade both with time and use. I would think a 
30-year-old 3 terminal regulator IC was also beyond its design life. So 
do you replace those 'anyway'? The damage done if one those fails is 
likely to greatly exceed the damage done if a capacitor fails.


Honestly, I've not seen all that many failed 3-terminal voltage regulators 
in the field. I've seen some which failed due to insufficient cooling or a 
loose heatsink, or with a hole blown in them after being hit with 24V AC, 
but not any that have failed short under normal use.


Do you replace all EPROMs in case they develop bit-rot (They are most 
likely way beyond their design life by now)?


I think like most of us on this list, anything I have which is mission 
critical gets backed up and can easily be reprogrammed if it fails. Most 
of the problems I've seen with bit-rot of EPROMs have been cases where 
their quartz windows were not originally covered. I use opaque foil 
stickers (I can see if I can find the part number for the stickers I use 
if anyone needs it) on any UV erasable memories I program and I haven't 
had issues with corrupt data.

RE: PDP 11 gear finally moved

[Tothwolf]

On Wed, 22 Jul 2015, tony duell wrote:

Given that a typical aluminum electrolytic capacitor costs anywhere 
from $0.12-$0.15 (4mm or 5mm diameter radials) to about $1.00 (12mm or 
16mm diameter radial), it also doesn't make much sense to desolder a 20 
year old part, spend at a minimum 5 or more minutes testing it, and 
then solder it back in. It it much more economical to pull the old part 
and install a new one and be done with it. (You also don't have to 
worry if the desoldering and resoldering process might have damaged the 
original parts end-seals.) That said, I personally pre-test new parts, 
in bulk, before I


I don't remove parts unless they have something to do with the problem I 
am solving. If the power rails are the right voltage with sufficiently 
low ripple then I look elsewhere for probkems.


put them into my stock, so I know ahead of time that I'm installing 
known-good parts.


You claim that electrolytics deteriorate with time whether used or not. 
How do you know the ones you install haven't deteriorated since you 
tested them?


When I pull capacitors from a board, I put them into numbered trays for 
testing. Each new part also gets another quick test before installation 
and the results of both get entered into a spreadsheet (along with date 
codes, part numbers, and any other data I have on hand). I did this 
initially for mission critical boards so I could provide the data to 
customers who needed that level of detail, but I later started doing this 
for all repairs because I found it wasn't all that difficult to do once I 
already had a system in place. When I'm testing old parts, I also note 
things like leaky seals, corrosion around the terminals, etc. Because of 
the historical data I've collected, I can also tell from my notes that 
there are definitely certain brand/series (both vintage and modern) which 
have common issues.

RE: PDP 11 gear finally moved

[Tothwolf]

On Wed, 22 Jul 2015, tony duell wrote:

On Wed, 22 Jul 2015, ANDY HOLT wrote:


Do you seriously replace both headlight bulbs when one fails? I know of
nobody who does that. Generally you carry a spare bulb kit and a screwdriver
and if a bulb fails, pull over and change it.


and - like the capacitor replacement question this is an it depends. 
For some cars - including the Mercedes A-class (at least earlier 
models) - it is almost impossible to change the headlight bulb when the 
car is at ground level because it is accessed through a hatch in the 
wheel arch, whereas if the car


ARGH!!!

But presumably you carry a jack and tools to change a wheel. Can you not 
just remove the wheel on the correct side to reach the hatch (not that I 
want to work on a car not supported on proper axle stands...)


Having had a number of bulbs that failed shortly (but not very shortly) 
after installation (nothing to do with headlamps, and not quartz-halogen 
bulbs so it was not contamination of the envelope that was the problem) 
I wonder if necessarily changing a good bulb is a good idea...


I can't say I've previously heard of that being done with automotive 
bulbs, but I do know that some pinball guys who do this. After a couple of 
lamps go out, they will replace them all at the same time because it 
usually isn't easy to change them, and once the lamps reach a certain 
number of power on hours, they start failing more and more frequently.

Re: PDP 11 gear finally moved

[Tothwolf]

On Tue, 21 Jul 2015, Mike Stein wrote:

I suspect that the real criterion for whether to shotgun-replace caps is 
who is paying/getting paid for the materials and labour ;-).


I dunno about that. When I've done commercial boards such as industrial 
process controllers and CPUs for customers with nearly unlimited funds, I 
charged the customer based on an hourly rate. Since I use a vacuum 
desoldering tool, changing out 10-15 aluminum electrolytics on a board 
took me not much more time than 1-2. Most of the time spent on a board 
that comes out of the field is spent on cleaning, testing (before and 
after repairs) and prep, and it only takes a few seconds to pull the 
solder off of a couple of component leads. Replacing aged electrolytics 
wholesale on these types of boards also meant I didn't need to worry that 
the same board would be back on my bench again in the next 3-6 months. 
These days, I'm not taking on any new commercial work though, there was 
just too much demand due to all those shoddy far-east made capacitors, and 
it meant I pushed aside all my own projects.


I guess from a business standpoint, if I had been trying to make extra 
money on boards repeat failing in the field and having to come back in for 
repairs over and over, changing out only 1 or 2 aluminum electrolytics 
would have made sense. That said, industrial process equipment tends to 
run 24/7 and is expected to be 100% reliable. If something shuts down, it 
tends to cost a heck of a lot of money, so I would no doubt have lost many 
customers.


FWIW I'm certainly not about to spend 100s of dollars, not to mention 
time spent in sourcing and replacing, to replace the caps in systems


100s? Where are you sourcing your components from? The typical board I 
rebuild has a component cost of about $20 or less. Smaller switchmode PSUs 
with a bunch of 10-18mm radials might be closer to $35-50. Larger PSUs 
/might/ cost closer to $100 if they have several large screw terminal 
capacitors in them. All things considered, that isn't very much money in 
today's dollars, and considering the full replacement cost of some of 
these boards (if they are even available), those preventive maintenance 
costs are an absolute bargain, /especially/ if you are doing the work 
yourself on your own time.



that are running perfectly just in case...


How do you -know- they are running perfectly? Just because a widget 
itself is functioning, you have no way of knowing if that capacitor is 
working 100% properly /unless/ you actually remove it from circuit and run 
a full battery of tests on it. Simply measuring the capacitance with a DMM 
while a capacitor is in circuit isn't good enough.


Given that a typical aluminum electrolytic capacitor costs anywhere from 
$0.12-$0.15 (4mm or 5mm diameter radials) to about $1.00 (12mm or 16mm 
diameter radial), it also doesn't make much sense to desolder a 20 year 
old part, spend at a minimum 5 or more minutes testing it, and then solder 
it back in. It it much more economical to pull the old part and install a 
new one and be done with it. (You also don't have to worry if the 
desoldering and resoldering process might have damaged the original parts 
end-seals.) That said, I personally pre-test new parts, in bulk, before I 
put them into my stock, so I know ahead of time that I'm installing 
known-good parts.


On many occasions I've cut open old aluminum electrolytics, and the guts 
very much do deteriorate with age. In addition to corrosion of the foil 
(black spots and pitting) and foil to terminal junctions (corrosion), one 
thing I particularly noticed was the more operating hours an aluminum 
electrolytic capacitor had on it, the more its electrolyte and paper 
insulator tended to smell bad compared to an otherwise identical (same 
brand and series) part that had very low hours. These are all clear signs 
of deterioration.


To those who advocate keeping old aluminum electrolytics in service, I 
have to also ask, would you also try to recondition 20 year old NiCd or 
SLA batteries and keep those in service too?


The bottom line really is, if you want something to be as reliable as you 
can possibly make it, you replace old aluminum electrolytic capacitors 
which are outside of their expected service life. If you don't care if 
something fails over and over, or you actually like to have the same 
widget on your service bench year after year, or month after month, you 
just replace 1 or 2.

RE: PDP 11 gear finally moved

[Tothwolf]

On Tue, 21 Jul 2015, tony duell wrote:

On Mon, 20 Jul 2015, Tothwolf wrote:

Yes, the grid cap would /usually/ be a non-polarized wax paper type, 
which tend to be very unreliable. I've yet to find a wax paper type 
which will pass a leak test and those are also on my replace on sight 
list.


Of course you wouldn't want to replace mica, ceramic, or plastic film 
parts without good reason, but if a set is going to be more than just a 
shelf queen, aluminum electrolytics and wax paper capacitors are a


It depends a lot on the circuit. If replacing the capacitor is going to 
involve major realignment and the original is probably OK and leakage is 
not going to do further damage (likely in the case of a tuning 
component) then I will leave it and only replace if it fails.


IMO an alignment is simply part of the restoration process. When I service 
a set, I do so expecting that it is going to be used and thus needs to 
have an accurate dial vs just sitting on a shelf. Simply installing 
replacement aluminum electrolytics and wax-paper capacitors is not likely 
to affect alignment. It is extremely common however to find sets where 
someone else has previously mucked up the original alignment in an attempt 
to work around electrically leaky wax-paper capacitors which have caused 
the band the drift.


must-replace item. Carbon film resistors in this sort of equipment 
should also be tested, however I only replace those which are either 
bad or out of tolerance (some brands held up better than others).


This is inconistent. A capacitor which is failing (starting to leak, 
say) may get worse. A resistor which is drifting may get worse. Either 
can do more damage when it fails. Why replace the cap and not the 
resistor?


Why is that inconsistent? If I test a carbon comp resistor and it measures 
within spec, there isn't much reason to replace it. Unlike an aluminum 
electrolytic capacitor, a carbon comp resistor is very stable chemically. 
Carbon comp resistors tend to drift due to absorption of moisture, and 
while it is possible to dry one out in a toaster oven at a controlled 
temperature, the resistor will again drift out again over time, so if one 
is out of spec, replacement is the best option.


I probably would replace certain safety-related capacitors in live 
chassis sets, like ones that isolate external sockets, using class Y 
replacements. But that;s about it.


That's a good idea, however something to keep in mind is that class Y 
safety rated capacitors are not designed not to short (and not put say a


I thought that was the difference between class X (will fail in a safe 
way, but may short) and class Y (will not short). The latter are to be 
used where 'failure of the capacitor may expose a person to electric 
shock' according to the data sheets I've read.


In general class X go across the mains, class Y from mains to ground.


Except that the chassis in modern equipment is /expected/ to be connected 
to ground, unlike a floating or hot chassis in a vintage radio. Both class 
X and class Y can fail short. A class Y tends to have a thicker dielectric 
and/or a lower voltage rating, which means it is less likely to fail 
short, not that is cannot fail short.


I consider replacing aluminum electrolytics to be preventive 
maintenance. One wouldn't drive a 20-50 year old car with original 
hoses, belts, and tires, and IMO it is just common sense to replace 
electronic components such as aluminum electrolytic capacitors which 
have extremely well documented life expectancies and failure rates.


I do wonder if this data is based on the cheaper components used in 
consumer electronics (paticularly things like AA5s) and that the 
capacitors used in computers were of a much higher quality and longer 
life.


Possibly. Radio repair shops of the AA5 era also had a vested interest in 
turning a set around as quickly (and as cheaply) as possible, and a set 
back in again in the same year for another repair was also good for their 
business. Back then, consumers expected their radios to need routine 
service, so people were less likely to even question it. I've come to this 
conclusion based on the types and quality of radio shop repairs I've seen 
in these old sets. I have a radio in my to-do queue right now (an AA5) 
which was owned by my grandparents, where a shop needlessly hacked the 
leads off a Centralab hybrid module and replaced about half of its 
functionality with some really cheap wax-paper capacitors and a handful of 
resistors (after searching for a number of years, I actually managed to 
find a NOS module for it, so that part of the circuit will be restored to 
its original condition when I eventually get to that project).


As far as shotgun-repairs go, one of my own pet peeves are those out 
there selling cap kits (usually really low quality [sometimes 
counterfeit]


Oh don't get me started


Cap kits or counterfeits? ;)

Best way to avoid counterfeits...do not buy modern name

RE: PDP 11 gear finally moved

[Tothwolf]

On Sun, 19 Jul 2015, dwight wrote:

I have rarely seen static damage to electronic parts. I can imagine that 
if I were in Nevada during winter time, I might see more. There were 
times when, even with a key to be the discharge point that my arm still 
jumped.
On parts, the ones I've seen that I could definitely attribute to static 
were, VFets with no zener input protection and the CMOS parts, 4051, 
4052 and 4053.
The VFets were killed with soldering irons that someone cut the ground 
wires so I couldn't really say it was static in the normal sense.
I doubt any power supply could ever be damage from a discharge to a 
output lead. The ratios of capacitance is too different. The human body 
just doesn't have enough capacitance to mean anything to a power supply 
filter capacitor.
Now, if your talking lighting as the source of static, I've even seen 
those static protection parts blown off boards.

Now that is static damage!
Tinker Dwight


Oddly enough, I have a Sangean ATS-803A (Radioshack DX-440) receiver on my 
bench right now which has static electricity damage. They used two Sony 
2SK152 JFETs (long since discontinued and virtually impossible to source) 
which can be damaged by static electricity merely by touching the 
telescoping antenna. I've replaced the two 2SK152 with Fairchild J113 
JFETs and retrofitted a pair of inverse-paralleled 1N4148 diodes just 
before the antenna selection switch (between ground and the switched side 
of the external antenna jack) to help prevent future damage to the 
replacement JFETs. The receiver still isn't working quite right just yet 
though. It currently works fine on broadcast AM up to 1620KHz (internal 
loopstick antenna) and broadcast FM with the external telescoping antenna, 
but at 1621KHz and above in AM mode, the set is totally deaf. It is 
supposed to use the external telescoping antenna for AM operation above 
1620KHz, but there is still a faulty component somewhere in that portion 
of the circuit.

RE: PDP 11 gear finally moved

[Tothwolf]

On Mon, 20 Jul 2015, tony duell wrote:

Replace - yes, *especially* if you don't have a big budget. Aluminum 
electrolytic capacitors are CHEAP and easy to obtain. Replacement 
semiconductors by comparison are expensive and can be quite difficult 
to find.


Err, have you priced the screw-terminal 'computer grade' electolytic 
capacitors that were used in these PDP11 power supplies. They are not 
cheap, if you can find them at all. And of course NOS ones might be as 
good or bad as the one that's already there. Conversely when I had a 
major disaster in a DEC power regulator brick some years ago (blew 
almost all the transistors and the 723) the replacement parts were easy 
to get (exact replacements, not just equivalents) and were not 
expensive.


I've not replaced any in a PDP11 power supply, however I have replaced 
them in other equipment with equally large PSUs. In the odd case where a 
computer grade screw terminal capacitor is extremely expensive or 
completely unobtainable (those which I've purchased were under $20-30) I 
might be willing to leave an original part in place, *if* it can pass a 
leakage test.



[...]

Ironically, 20-30 years ago this same mindset used to persist with 
people who collected vacuum tube (valve) based radios and television, 
however that attitude no longer seems to be present in those 
communities today (not worth risking an irreplaceable transformer or 
inductor over $5.00-$10.00 worth of aluminum electrolytics).


Odd... I know plenty of people who restore old valve radios and audio 
stuff and not one will blanket-replace all the aluminium electrolytics. 
There is a capacitor that I (and they) would check very carefully, but 
that's not an electrolytic. I refer of course to the coupling capacitor 
to output valve grid. In a lot of radios this is connected to the anode 
(plate) of the audio ampilfier triode so if it leaks it puts a +ve 
voltage on the output valve causing far too high an anode current there.


But even then I (and everyone else I know) would test it, not just 
replace it. Some of those capacitors are very reliable and the 
replacements you get not any better.


Testing each aluminum electrolytic and wax paper capacitor vs replacing 
them all doesn't seem to be the prevailing norm in the vintage radio 
communities today.


Yes, the grid cap would /usually/ be a non-polarized wax paper type, which 
tend to be very unreliable. I've yet to find a wax paper type which will 
pass a leak test and those are also on my replace on sight list.


Of course you wouldn't want to replace mica, ceramic, or plastic film 
parts without good reason, but if a set is going to be more than just a 
shelf queen, aluminum electrolytics and wax paper capacitors are a 
must-replace item. Carbon film resistors in this sort of equipment should 
also be tested, however I only replace those which are either bad or out 
of tolerance (some brands held up better than others).


I probably would replace certain safety-related capacitors in live 
chassis sets, like ones that isolate external sockets, using class Y 
replacements. But that;s about it.


That's a good idea, however something to keep in mind is that class Y 
safety rated capacitors are not designed not to short (and not put say a 
floating chassis at mains potential). Safety rated capacitors are instead 
designed to blow clear while not catching on fire (or otherwise be 
self-extinguishing), should they short out across mains potential. This 
means should a class Y part short, a floating chassis could still be 
placed at mains potential, and that capacitor is not going to blow clear. 
That said, anything is going to be better than a wax paper capacitor, and 
a class Y safety rated part is also much safer in this sort of application 
than a ceramic disc.


Incidentally, do you shotgun-replace 7805s and other 3 terminal 
regulators? If not, why not? They can fail, and if they do they do a lot 
more damage than a failed capacitor.


As a general rule, I do not make shotgun-repairs to electronic equipment. 
While I may replace certain failure-prone parts outright on sight, I still 
prefer to determine which part(s) are causing a malfunction.


I consider replacing aluminum electrolytics to be preventive maintenance. 
One wouldn't drive a 20-50 year old car with original hoses, belts, and 
tires, and IMO it is just common sense to replace electronic components 
such as aluminum electrolytic capacitors which have extremely well 
documented life expectancies and failure rates.


As far as shotgun-repairs go, one of my own pet peeves are those out there 
selling cap kits (usually really low quality [sometimes counterfeit] 
capacitors, too) to newbies which also include a bunch of semiconductors 
(diodes, voltage regulators, and transistors) on the theory that those 
parts fail because they run hot. I've gotten to the point where I will not 
even attempt to service a board which has been botched up by a fat 
fingered newbie who 

RE: PDP 11 gear finally moved

[Tothwolf]

On Mon, 20 Jul 2015, Rich Alderson wrote:

On Sat, 18 Jul 2015, Peter Coghlan wrote:

Rich Alderson ri...@livingcomputermuseum.org wrote:


It is generally a good idea to re-form electrolytic capacitors in 
power supplies, and to bench check the power supplies (under some 
kind of load) before actually applying power to the whole unit.


It is always a good idea to replace electrolytic capacitors in power 
supplies. The rest of the advice is sound.


Can you please clarify if this statement represents the policy of the 
Living Computer Museum or is it something more personal?  Perhaps some 
qualification or a re-phrasing would be useful as it does not appear to 
make sense as it stands?


This is the policy of Living Computer Museum.  It is based on the 
cumulative experience of multiple very senior electrical engineers[1] 
doing restorations here, in conjunction with industry white papers with 
tables of decay rates for the aluminum electrolytics that indicate that, 
*no matter what*, they lose capacitance over time, until c. 14 years 
from manufacturer date they are at 10% of rating.


[...]

I think you may have seen or participated in some of the many 
discussions we have had on this topic on this list?  In light of these 
discussions, I find it hard to see how a categorical statement such as 
this one could be justified.


Since the proponents of this practice make categorical statements with 
no evidence that they want to listen to reasoned explanations, I long 
ago gave over trying to convince them, and simply respond when someone 
makes a statement to a newbie which will result in frustration and 
failure for the unfortunate recipient of this advice.


Rich,

Do you happen to have a list of whitepapers and/or links on hand? I too am 
getting tired of repeating the same thing over and over and compiling this 
sort of information in a single location might be helpful. Buried in my 
own archives I have quite a few papers and datasheets in pdf format, but 
they are all mixed in with everything else so finding them would be quite 
a challenge.

Re: PDP 11 gear finally moved

[Tothwolf]

On Mon, 20 Jul 2015, Mark J. Blair wrote:

Now on the topic of capacitors: The only component type that I replace 
on sight at this point are the Rifa paper-dielectric EMI suppression 
caps. Had one go incendiary on me so far, and I do a replace-on-sight 
routine on them because my hypothesis of the failure mechanism(*) leads 
me to believe that they're all likely to burn up once the plastic shell 
has developed any cracks. They're easy to recognize: Rectangular, with 
transparent yellow plastic housings, which are usually crazed with fine 
cracks. Different caps which should not be subject to the same failure 
mechanism are easily available.


(*) Paper dielectric is said to absorb moisture from the atmosphere if 
not sealed. So, I presume that once the yellow plastic shell cracks from 
old age, moisture gets in, and then the caps break down under power. I 
replace these with poly film safety-rated caps with suitable ratings, 
since the poly film shouldn't absorb significant moisture even if the 
housing seal fails.


Absolutely! I didn't mention those in my previous list since I was focused 
on aluminum electrolytics, but those yellow Rifa parts are an especially 
sore spot in older test gear. My own theory on these is that the swelling 
of the paper is what is causing them to crack. I'm not sure what chemical 
they treat the paper with, but it apparently doesn't hold up long term 
and/or this is just their failure mode as they age and wear out. While 
Rifa still makes these very same safety capacitors, I've been replacing 
them with MKP types from TDK which won't fail in the same way.


Oddly enough, those failing class X and class Y Rifa parts I see seem to 
be early 1980s to mid 1990s vintage gear, which puts them in that same 
20-30 year age I tend to use for replacing aluminum electrolytics.


Another capacitor type which I replace on sight are any wax paper 
capacitors such as you would find in tube (valve) based equipment. The wax 
coated tubular types are easy to spot, but the epoxy covered parts (black 
beauty, bumble bee, etc.) fail the same way. After replacing 100s, if not 
1000s of the things over the years, I've yet to find one, even NOS (which 
always seem to turn up in lots of parts from estates and such), which 
would pass a leak test.


I replace wax paper types with polyester (mylar), polystyrene or ceramic 
discs, depending on how they are used in the circuit (note however that 
for wound foil types, modern replacement parts do not mark the outside 
foil, which needs to be at ground potential in many tube circuits, 
otherwise the circuit can pick up noise and hum).

RE: PDP 11 gear finally moved

[Tothwolf]

On Fri, 17 Jul 2015, tony duell wrote:

Perhaps.  But not all of it, certainly.  I'm currently four for four 
fixing dead flatscreens by re-capping their power supplies; I imagine 
others have similar experiences.  It's not a huge stretch to imagine


This could be taken to show that modern capacitors are not reliable, and 
given that there are plenty of 40-year-old ones still in use in various 
classic computers here it would be better to leave them as-is


It really depends. If I'm having to replace filter capacitors in a faulty 
PSU or monitor, even if I've isolated the problem to one or two 
capacitors, I would be a fool not to replace them all because the next 
part that fails will be one of those which I didn't replace (been there, 
done that, own the tee shirt). A standard 85C or 65C rated 20-30 year old 
aluminum electrolytic is simply past its useful service life.


More seriously, a lot of modern consumer stuff seems to have 
marginally-rated capacitors (and the use of 85 degree ones doesn't 
help). Possibly on those it is a good idea to replace them. But the ones 
in PDP11s were good quality at the start and were over-spec'd in 
general.


With modern electronics, there are high quality parts and there are really 
cheap parts. Even though the high quality parts are about the same price 
as the really cheap parts when purchased in small quantity (in the one-off 
to a few 1000 quantity), profit-driven consumer electronics manufacturers 
are still going to use the cheaper parts when they can save even $0.01 or 
$0.005 per component or even a few cents on the overall cost of the 
complete widget.


Many of these manufacturers also design their widgets to last for the 
warranty term and no more. If the consumer gets 2-3 years or more out of 
said widget, those manufacturers consider it a loss in terms of potential 
profits. In these cases, wholesale replacement of really cheap capacitors 
with high quality versions from top tier manufacturers (Panasonic, 
Nichicon, Rubycon, etc) can be a /really/ good idea. That said, even the 
top-tier capacitor manufacturers have lower end lines of parts, so it pays 
to do your homework and choose a longer life (usually lower ESR, meaning 
less internal heating and thus longer service life) part when sourcing 
replacements.


Even vintage Mallory and Sprague parts are not without their faults. I 
recently replaced a bunch of early 1980s era Mallory capacitors which 
tested good, but when desoldered from the board, had brown crusty stuff 
around the safety vent in their bottom rubber seals. They might have 
continued to work ok for another year or even 10 years, but the high 
quality replacement parts I put in will be good for at least another 20-30 
years. (The replacement parts also worked better as the DC rails had lower 
ripple after they were installed).


that other power supplies may have similar issues; even if it turns out 
to not be the case, there is probably at least a little can't hurt 
anything, right? running around.


Ah but it can hurt. Damage to the PCB (unlikely, sure), the new part 
might be faulty and thus introduce more faults, you might make an error 
fitting it, and so on. I prefer to only replace that which needs 
replacing.


It really is a case by case basis, however in PSUs, CRT monitors, and 
similar where the components are exposed to higher temperatures, it really 
makes sense to replace 20-30 year old aluminum electrolytics wholesale.


I guess another way to look at it is that an electronic device might still 
be functioning with old aluminum electrolytic capacitors, but is it still 
functioning as good as it was when it was new? A vintage device might have 
used really high quality aluminum electrolytics when it was made, but even 
high quality parts have a finite service life. What you have to decide is 
where to draw the when considering wholesale replacement of aluminum 
electrolytics, which with vintage electronics, I've found tends to be 
somewhere around the 20-30 year point.

Re: Old HP test equipment power connectors...

[Tothwolf]

On Thu, 28 May 2015, Jules Richardson wrote:

On 05/27/2015 04:18 PM, Chuck Guzis wrote:

I did a little checking today--I compared a male 163-type receptacle 
with a C14 receptacle.  The mounting ear holes appear to have the same 
spacing; the C14 is about 3/4 thick, where the 163 (metal shell) is 
about 1/2 thickness, so you'd need to enlarge the mounting holes about 
1/8  on the top and bottom.


Aha, I'm not a fan of non-reversible mods if I've got an alternative.

I'm leaning toward the C5/6 connectors at the moment; I see the cables 
around once in a while, but I'm not sure about the availability of 
chassis-mount sockets (I expect they're generally PCB-mount).


Option 2 is to use a mounting plate with a grommet and simply have a 
permanently-attached power cable - separate power cables on things are 
just there to get lost anyway ;-)


I'll arrange a trip back to the site where some of the test equipment 
came from though as there may be a nest of the original cables there - 
the problem will be finding them, as it was a bit of a dumping ground 
for ancient tech.


Try these:

Schurter 0724 series:
  4300.0100 - solder terminals
  4300.0101 - pcb terminals

Schurter 2561 series:
  6160.0001 - solder terminals

Schurter 2562 series:
  6160.0002 - pcb terminals

http://www.schurter.com/Components/Connectors/Connectors-Inlets-Outlets

http://www.mouser.com/Connectors/Power-Connectors/AC-Power-Entry-Modules/_/N-axiqi/

[I couldn't do much more than a quick search since I'm really busy with 
flood cleanup.]


Keep in mind the C5/C6 couplers are only rated for 2.5A.

Something else other list members may find interesting is the Bulgin 
PX0578/63. Those are a C13 input coupler with 0.25in (6.3mm) quick connect 
terminals. I'm using some of these to connect power to some really small 
SeaSonic switch mode PSUs for embedded applications.


Both Bulgin and Schurter have all sorts of IEC 60320 connectors/couplers, 
but the best way to find them is to look at the datasheets and not 
Mouser's search. Mouser often has the terminations, mounting type, and 
sometimes even the coupler type listed wrong, so I always use the 
manufacturer's part number when searching.

Re: Old HP test equipment power connectors...

[Tothwolf]

On Tue, 26 May 2015, Chuck Guzis wrote:

On 05/26/2015 08:28 PM, Brent Hilpert wrote:

Like wulfman and chuck and as described on my page, I replace the 
chassis inlet whenever I can, although occasionally it's not possible 
due to proximity of other chassis elements as the IEC inlet is slightly 
larger.


Belden made a lot of cords for HP and others, and sometimes you can still 
find them NOS in their original packages.


Right now, I'm cursing the guy who thought that the cloverleaf or 
mouseketeer power receptacle was a good idea.  I'm sitting here 
looking at an HP ScanJet wondering if it would be worth the effort to 
replace it.


Fer heaven's sake, what was wrong with the IEC connector?


Which specific IEC connector? A lot of people think of the C13 as the only 
IEC connector, but there is a whole family of IEC 60320 (IEC 320) 
connectors. If by cloverleaf or mouseketeer you are referring to the 
C7 or C5 couplers, those types are part of the IEC 60320 standard. 
https://en.wikipedia.org/wiki/IEC_60320 (Full disclosure: I have access to 
copies of the official 60320 standards and I spent a good deal of time 
working with some other editors on the material for Wikipedia). Now, if 
you want to talk about really weird connectors, Sony had a number of power 
connectors which can be incredibly hard to find replacements for today...