I'm looking at what the spec says. ;-) The read command delay from the
head set command is 15us (so I was wrong) but still not a lot of time
(that is after a head set, a read command must be at least 15us later).
Since I'm not looking at formatted data rate (just handling the raw bit
I haven't looked it up but I bet the head switch time is a lot longer than 1-2
usec - that's what the leading gap is for and the sync took most of the gap
back in those days.
The issue is sustained data rate isn't it? The ESMD raw data rate is 24 Mb/s
but the formatted data is something
As mentioned, I find it best to cut the pins off the IC right at the IC
body and then remove them individually. Once the IC is removed, I use a
third hand to hold the board vertically, and then grab each pin with
tweezers or needle-nose pliers from one side of the board and lightly
touch the
I ran the numbers for Zynq FPGAs. First of all for ESDI and SMD the
head switch time is 1-2us (basically the time it takes for the clocks to
re-lock on the new data).
Two tracks isn't sufficient (which is the "other" track...you will be
wrong).
So I decided to go and have a full cylinder
Sorry, not me.
On Fri, Apr 15, 2022 at 6:18 PM Van Snyder via cctalk
wrote:
> If you're the guy I sent an IBM typewriter to, contact me. I found a
> spring that was part of it. I thought I had lost it forever.
>
> Van Snyder
> van.sny...@sbcglobal.net
>
>
There are still HP3000 systems being used in business critical functions,
12(?) years after the HP end-of-life date (no manufacturing or support)
for the product line. (From a business continuity perspective that's
insane.) Hardware support is not based on new manufacturer parts with
warranty, but
On 4/15/22 17:12, W2HX wrote:
> Just be careful around cerroblend. According to Wikipedia...
>
> "... is a metal alloy that is useful for soldering and making custom metal
> parts, but which is toxic to touch or breathe vapors from."
> "...is toxic because it contains lead and cadmium, and
> On Apr 15, 2022, at 6:49 PM, Peter Coghlan via cctalk
> wrote:
>
> We occasionally hear of aged computers being employed in the nuclear
> power industry, certain military applications or long lifed medical
> equipment for example. I imagine that these machines can have a
> significant
This was the approach IBM used in it's first RAMAC RAID where I think they had
to buffer a whole cylinder but that was many generations ago
(my copy of the specs may not be exact):
Buffering a whole cylinder, or a whole surface, of the RAMAC was no big deal.
One hundred surfaces (52 platters,
We occasionally hear of aged computers being employed in the nuclear
power industry, certain military applications or long lifed medical
equipment for example. I imagine that these machines can have a
significant commercial value long after their contemporaries which are
not involved in these
> On Apr 15, 2022, at 6:54 PM, Fred Cisin via cctalk
> wrote:
>
> On Thu, 14 Apr 2022, Tom Gardner via cctalk wrote:
>> This was the approach IBM used in it's first RAMAC RAID where I think they
>> had to buffer a whole cylinder but that was many generations ago
>
> (my copy of the specs
Just be careful around cerroblend. According to Wikipedia...
"... is a metal alloy that is useful for soldering and making custom metal
parts, but which is toxic to touch or breathe vapors from."
"...is toxic because it contains lead and cadmium, and contamination of bare
skin is considered
For very-difficult de-soldering, I use a variation on the Chip-Quik
idea. I take a hunk of Cerrobend 158 fusible alloy and a file and make
a small pile of powder from it. I then pack the powder around the pins
of the IC to remove and heat the area using the light from a 75 watt
PAR-38 halogen
If you're the guy I sent an IBM typewriter to, contact me. I found a
spring that was part of it. I thought I had lost it forever.
Van Snyder
van.sny...@sbcglobal.net
Once the chip is out, for cleaning out the holes, I used a spring loaded
solder sucker on one side of the board, with soldering iron on the other
side.
also, solder wick
sometimes a wooden toothpick
in extreme cases, a small drill bit turned by hand in a pin vise (NOT
chucked up in a powered
On Thu, 14 Apr 2022, Tom Gardner via cctalk wrote:
This was the approach IBM used in it's first RAMAC RAID where I think
they had to buffer a whole cylinder but that was many generations ago
(my copy of the specs may not be exact):
Buffering a whole cylinder, or a whole surface, of the RAMAC
If the Klein cutters are too bulky, you may care to investigate.
Lindstrom 7191 https://uk.rs-online.com/web/p/cutters/3320341 are the usu first
resort small cutters - they should be fine enough for 0.1" pitch ICs.
A finer pair are Bondline 1570
I bought a Hakko FR301-03 in mid 2020 and, while I haven't used it for a lot, I
can attest it has worked very well for what I have done. I have used it to
replace the RIFA caps on the boards of 3 H7864 power supplies and the pico
fuses on several KDJ11-B 11/73/83 CPU boards. In each case the
I do have some diagonal cutters, but although small they seem to be still too
bulky to reach the pins. I will have to try to find some finer ones. These seem
to look OK:
https://uk.farnell.com/klein-tools/d275-5/wire-cutter-diagonal-127mm/dp/2839543
Also, I have seen the recommendations
Rob
I would imagine that an 11/24 CPU is at least a 4 layer board, with power
planes and hopefully thermal reliefs at pins connected to a plane. The pins
you will be having difficulty with are most likely on the Gnd or Vcc plane. I
often leave those pins for last, once in the groove. And,
On 4/15/22 12:46 PM, Malte Dehling wrote:
On Fri 15. Apr 2022 at 11:43, Alan Perry via cctalk
wrote:
On 4/15/22 9:53 AM, Dave Wade G4UGM via cctalk wrote:
>> -Original Message-
>> From: cctalk On Behalf Of Alan
Perry via
>> cctalk
>> Sent: 15 April 2022
I've been tinkering with a PDT-11/150 lately. It's a little
inconvenient to work on, since it doesn't have a simple way to transfer
files back and forth (KRTMIN doesn't work when transferring files to the
box, just from the box, for some reason I haven't been able to puzzle
out, and pasting
On Fri 15. Apr 2022 at 11:43, Alan Perry via cctalk
wrote:
>
> On 4/15/22 9:53 AM, Dave Wade G4UGM via cctalk wrote:
> >> -Original Message-
> >> From: cctalk On Behalf Of Alan Perry
> via
> >> cctalk
> >> Sent: 15 April 2022 16:00
> >> To: cctalk@classiccmp.org
> >> Subject: Re:
I would not attempt any desoldering without my hakko 808. I never leave home
with out it. While you are sucking and heating the pin, wiggle the pin and it
work great. I've desoldered 40 pin chips without trouble, they drop right out
of the board. I desoldered this 40 pin chip from a working
On 4/15/22 12:43 PM, Alan Perry via cctalk wrote:
The note on it says that it doesn't boot, but they had the same note on
the Axil 320 (SS20 clone) that I got from them and it booted up fine
once I put a HDD in it.
There's posting and then there's booting into an OS. The former is most
On 4/15/22 9:53 AM, Dave Wade G4UGM via cctalk wrote:
-Original Message-
From: cctalk On Behalf Of Alan Perry via
cctalk
Sent: 15 April 2022 16:00
To: cctalk@classiccmp.org
Subject: Re: AlphaServer 2100s available
I wouldn't expect commercial value to come into the discussion on this
On 15/04/2022 18:49, Rob Jarratt via cctalk wrote:
I am using a fairly cheap desoldering station (this one
https://cpc.farnell.com/duratool/d00672/desoldering-station-uk-eu-plug/dp/SD
01384?st=duratool%20desoldering). Its spec in terms of vacuum pressure is
equivalent to that of the professional
I have to second this comment.
I learned to solder in the early 70s building kits and again
professionally in the early 80s.
In the early days of thicker circuit boards (2 layer only). A solder
sucker and solder wick would work.
However, the most expedient and safest way in terms of
I am trying to remove an IC from my PDP 11/24 CPU, a DS8641. I am really
struggling to desolder it. I am using the technique of applying fresh solder
and then removing it. But after multiple cycles of this I think I am
starting to damage the PCB.
Are there any tips for removing ICs?
Thanks
Rob
Cut the pins with a very sharp set of dykes then remove them one at a time.
Then use flux and detailer braid to remove the solder
On April 15, 2022 1:49:33 PM EDT, Rob Jarratt via cctalk
wrote:
>I am trying to remove an IC from my PDP 11/24 CPU, a DS8641. I am really
>struggling to desolder
I am trying to remove an IC from my PDP 11/24 CPU, a DS8641. I am really
struggling to desolder it. I am using the technique of applying fresh solder
and then removing it. But after multiple cycles of this I think I am
starting to damage the PCB.
I am using a fairly cheap desoldering station
> -Original Message-
> From: cctalk On Behalf Of Alan Perry via
> cctalk
> Sent: 15 April 2022 16:00
> To: cctalk@classiccmp.org
> Subject: Re: AlphaServer 2100s available
>
> I wouldn't expect commercial value to come into the discussion on this list. I
> am wondering what other
Texas Instruments was the first second source to create a Token Ring chipset,
the TMS380. When we pointed out to them some the IBM’ism features we’d prefer
to be fixed for 802.x compatibility they claimed they couldn’t because of
legal agreements with IBM. The TI chipset had other issues
I suggest if we are talking about an emulator it really isn't necessary to have
the entire disk in DRAM, two tracks of DRAM acting as a buffer with a modern
HDD holding the emulated drive's data should be fast enough to keep any old
iron controller operating without missing any revolutions.
I wouldn't expect commercial value to come into the discussion on this
list. I am wondering what other hobbyists pay in order to gauge whether
the price that a local recycler is asking for one (which was around
$100) is fair.
On 4/15/22 3:30 AM, Peter Coghlan via cctalk wrote:
It's worth what
On 4/15/22 4:30 AM, Peter Coghlan via cctalk wrote:
However, it doesn't seem to have any commercial value.
I suspect that the recent VAX Hobbyist License Program's expiration will
be a shot in the arm for older Alpha systems value as some people
migrate to Alpha to legally run OpenVMS as a
It's worth what someone is willing to pay for it and this will vary widely.
I got one for EUR 20 in 2006. I didn't think this was a bargain because
I was under the impression I was getting it for free before I travelled
to pick it up. The previous owner had no further use for it and needed
the
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