Re: Cleaning RK05 packs (Was: LGP-30 Memory Drum Update)

[Chuck Guzis]

On 01/05/2017 05:13 PM, allison wrote:
>> Freon TF works well on everything.  Too bad it's not available.
>> 
>> Is it still used for aircraft electronics?
> No its been obsoleted.  There are many other similar but not
> fluorinated hydrocarbons that are preferred and also good old soap
> and water.

No, it's been banned.  "Obsoleted" to me carries the implication that
there's something better.  TF was banned under the Montreal Protocol not
for its toxicity, but for the ozone-depletion characteristic of the
stuff when it was released into the atmosphere.  Same goes for most
chlorinated refrigerants.

HCFC-225 had been an adequate substitute, but that was phased out in
2015.  Too bad--it was almost as good as a cleaner.

Techspray (and NASA and a bunch of other outfits) have proposed some
possible alternatives;

https://www.techspray.com/t-ak225ban.aspx

If these were my packs, I'd drop them a line and see what they recommend
for the specific application.

FWIW, I buy my denatured ethanol from the paint store--it's about as
water-free as it's possible to get, usually with some methanol commonly
added as a denaturing agent, although other substances can be used.
This was a practice started in 1906 so that manufacturers could be
exempted from alcohol taxation.

During Prohibition, the government, responding to a higher moral
standard, reformulated the denaturing agents, making them even more
lethal.  The result was dramatic--in 1928, 700 people died in New York
alone from consumption of industrial alcohol.  Oddly, the 18th amendment
only forbade manufacture, sale and transportation of alcohol.
Consumption was still perfectly legal.

Paint-store alcohol is free of water because it's commonly used as a
shellac solvent/carrier.  Any appreciable amount of water results in a
cloudy finish.

FWIW,
Chuck

Re: Cleaning RK05 packs (Was: LGP-30 Memory Drum Update)

[Jon Elson]

On 01/05/2017 11:38 AM, Pete Lancashire wrote:

you could test various solvents with a Q-tip to make sure they don't cause 
damage.

And a week later after the binder had decomposed what are you going to do ?


That's why you test in a non-critical area, and then let it 
sit for a while to make sure it doesn't cause slow 
deterioration.  And, of course, with a general idea of the 
material (plated nickel vs. oxide/epoxy) you can select 
solvents that are known to not attack that material.


Jon

Re: 12 years later sill looking for...

[Ian Finder]

Might help if you put specifically what you're looking for in the subject
line.

Or somewhere else clear.

Would also help a bit if your message were comprehensible.


On Thu, Jan 5, 2017 at 17:38 allison  wrote:

> <
> contains <
> controller Card] <
> schematic and fix <
> instrument may even be from <
> would be fun to get it operational. I repaired the CRT and foudn it
>
> generally less than useful and repurposed the CRT, Power supply and case
>
> for a Embedded ELF system... with disk. So now I have the three STD
>
> boards and 4 slot backplane... THey do have T-BAR on them and I can do
>
> one of two things with them strip them for the CPU, SIO, RAM, EPROM,
>
> SMC5027E CRTC. As is without manuals or other useful info they are junk
>
> to be reused. Ideally with far more detailed info like schematics make a
>
> dedicated z80 system. So I post it again... Allison
>
>
>
>
>
>

Re: cctech Digest, Vol 30, Issue 15

[Tim Mann]

For what it's worth, xtrs (http://tim-mann.org/xtrs.html) emulates LD A,R
by putting an 8-bit random number in A. Of course that's cheesy and wrong
-- especially bit 7 being random instead of retaining a 0 from reset or the
last value written to it -- but at least it works OK with Ethan's
subroutine. The subroutine may loop a few times due to the value randomly
being negative or zero until it escapes the first time the value is
randomly positive.

xtrs sets the sign and zero flags according to the value, and does
something complicated with the other flags that I don't remember the reason
for -- but it might be correct; i think I got it from some reference on the
web last time I hacked on that instruction.

The pointer that someone posted to
http://www.worldofspectrum.org/faq/reference/z80reference.htm#RRegister may
inspire me to fix the emulation, though it looks like a bit of work to get
it exactly right...

On Thu, Dec 15, 2016 at 10:00 AM,  wrote:

> Message: 10
> Date: Wed, 14 Dec 2016 17:34:29 -0500
> From: Ethan Dicks 
> To: "General Discussion: On-Topic Posts" 
> Subject: Re: Z-80 code question about a loop that depends on the
> contents of the refresh register
> Message-ID:
> 

Re: Cleaning RK05 packs (Was: LGP-30 Memory Drum Update)

[allison]

On 01/05/2017 07:15 PM, Chuck Guzis wrote:
> On 01/05/2017 03:24 PM, David Bridgham wrote:
>
>> This question of whether Simple Green was aluminum safe came up in
>> the aircraft world a few years back and the answer turned out to be
>> that some ingredient in there is mildly corrosive to aluminum.  Not
>> badly so and if you managed to flush it off with water then no
>> problem but if a bit of cleaner were to weep into a crack and not get
>> get cleaned off then over time it might be a problem.  Not too long
>> after that Simple Green came out with a new formulation, Simple Green
>> Extreme or something like that, that *was* aluminum safe.  So look
>> for the Simple Green that's sold for cleaning airplanes if you're
>> cleaning around aluminum.
Lots of ifs, mights, and maybes.   My knowledge is from actually owning
and maintaining a Cessna since 1979 and so far that has not been an issue.
FYI often cleaning the bird is good no matter what you use as salt spray
and
other things it can be exposed to are far worse.  Like acid rain and soot
from fires.

>
> Freon TF works well on everything.  Too bad it's not available.
>
> Is it still used for aircraft electronics?

No its been obsoleted.  There are many other similar but not fluorinated
hydrocarbons that are preferred and also good old soap and water.


Allison

>
> --Chuck
>

12 years later sill looking for...

[allison]

<

FOR SALE: Commodore PET 8032 like new in original box

[Sellam Ismail]

I have put up for sale on the Vintage Computer Marketplace a near pristine
Commodore PET 8032 in its original box.

http://www.vcfed.org/forum/showthread.php?55679-Commodore-PET-8032-Brand-New-in-Original-Box-w-manuals-and-accessories

If interested, please inquire on the VCM or direct to me through e-mail.

Thanks!

Sellam

Apple //c Prototype, Sphere 1, UniCom 141p for sale (and more)

[Sellam Ismail]

Hello All,

I have put up for sale on the Vintage Computer Marketplace the following
items:

Apple //c Prototype
http://www.vcfed.org/forum/showthread.php?55676-Apple-c-Prototype-for-sale

Sphere 1
http://www.vcfed.org/forum/showthread.php?55677-Sphere-1-early-Personal-Computer-with-integrated-keyboard-and-display

UniCom 141p
http://www.vcfed.org/forum/showthread.php?55678-Unicom-141p-First-commercial-product-with-Intel-4004-microprocessor

I also have a lot more machines of all kinds remaining in my collection
that I am selling.  Most of the machines in this post are still available
(though the prices listed are obsolete as this is an old post):

http://www.vcfed.org/forum/showthread.php?51781-Mulitple-and-divers-computers-for-sale

All prices are negotiable.  The intent is to sell these items.

Thanks!

Sellam

Re: Cleaning RK05 packs (Was: LGP-30 Memory Drum Update)

[Marc Howard]

"A pack inspector is a handy thing to have (spinle with microscope and
illuminator on the rack and pinion)"

Can you post a picture of this critter?  Is it something we could 3D print?

Thanks,

Marc

On Thu, Jan 5, 2017 at 6:40 AM, Al Kossow  wrote:

> isopropyl alcohol works. TFE is better, if you have some stashed.
>
> If you can find them anywhere, Texwipe made a plastic wand that looks like
> a tongue depressor with a slit down the middle and a lint free sleeve
> called the Texsleeve (tx300 sleeve, tx800 wand) that you would use to
> clean heads
>
> Minor head crashes leave a tar-like residue that you need to remove. A
> pack inspector
> is a handy thing to have (spinle with microscope and illuminator on the
> rack and pinion)
> to look for surface damage.
>
> On 1/5/17 5:22 AM, Noel Chiappa wrote:
> > > From: Klemens Krause
> >
> > > We clean our RK05 disks in a very robust way: with cheap burning
> spirit
> > > and paper towels. ... We rubbed away thick black traces from
> occasional
> > > head crashes and we never removed the oxide coating with this
> torture.
> >
> > I am about to get a large batch of RK05 packs, so I am interested in the
> > details of this.
> >
> > First, what is 'burning spirit'? (I assume this is a straight translation
> > into English of some German term, but not knowing German... :-) After
> poking
> > around with Google for a while (hampered no little by the fact that it's
> the
> > name of a band, and also a term in World of Warcraft :-), it seems like
> it
> > might be acetone?
> >
> >   Noel
> >
>
>

RE: Introduction to DECSYSTEM-20 PDF?

[Rich Alderson]

XKLeTen.PaulAllen.com changed names a long time ago.

Your account can be found on Toad-1.LivingComputerMuseum.org, and the PDF
is in DOC:.

Rich

-Original Message-
From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Seth Morabito
Sent: Monday, December 19, 2016 9:54 AM
To: cctalk@classiccmp.org
Subject: Introduction to DECSYSTEM-20 PDF?

I'm looking for a PDF of "Introduction to DECSYSTEM-20 Assembly
Language Programming" by Ralph E. Gorin. It used to be hosted
on PDPPlanet (xkleten.paulallen.com), but that's been down for a while.
Does anyone else have a copy they could send me?

Best Wishes,

-Seth
-- 
Seth Morabito
s...@loomcom.com

Re: Cleaning RK05 packs (Was: LGP-30 Memory Drum Update)

[allison]

On 1/5/17 12:30 PM, Al Kossow wrote:


On 1/5/17 9:22 AM, j...@cimmeri.com wrote:


As Allison taught me, the oxide surface on platters / drums is just a form of 
inactive RUST.. and therefore, unaffected
by water (no, the water doesn't cause it to start rusting further).

The interface between the aluminum platter and the steel sector ring 
would be a really bad thing to get water into.
Simple Green is a earth safe (Eco) detergent with a PH of 8.5 to 9.5.  
Safe for many things
as a mild great and organic residue remover.  Used that or Woolite for 
washing aluminum

aircraft for decades.

Water is not the hazard, allowing it to remain without drying is as it 
promotes corrosion.

Pure water (non-ionic) is mostly inactive.

FYI: Decades ago I used to do radio repair for the maritime set and a 
salt dunked radio
that was still dripping from its dunking in salt water was immediately 
without prejudice
immersed in clean water.  It was then again immersed in new fresh clean 
water.  The goal
was to remove the salt and then DRY (in a 160 degree Fahrenheit oven) 
the unit before
active corrosion could take over.  It was usually successful if the unit 
hadn't remained
submerged for more than a few hours  or allowed to sit around for more 
than a few
hours as if it it electrolytic corrosion from dissimilar metals would 
take over and kill it.
It was also effective on intermittent marine gear that had gotten flaky  
from salt tracking

on the board over time.

Allison

Re: Cleaning RK05 packs (Was: LGP-30 Memory Drum Update)

[allison]

On 1/5/17 10:56 AM, Mouse wrote:

In the US, "rubbing alcohol" is mostly denatured ethanol (though "isopropyl$

Interesting.  I don't think I've ever seen a bottle of "rubbing
alcohol" that was anything but isopropanol-and-water.  But I'm more
Canadian than US.

Many are possible in the local apothecary (aka drug store in local lingo).

ISO70% + water
ISO91% + water
Ethanol (denatured)+ water

Then there are products with oil of wintergreen (green color) and other 
additives

and are identified on label.


I would suggest avoiding these blends of random chemicals made with no real $

Or, more precisely, with _different_ concern for purity.  For rubbing
alcohol you want to avoid biologically active contaminants, but
dissolved solids per se don't matter.  Here, you care about dissolved
solids but don't much care about things that might be biologically
active, as long as they evaporate without residue.
Generally there are no solids in the first three and are safe for 
cleaning gear

is the materials are not affected by the alcohol in use.


Which leads me to tentatively suggest gasoline (West Pondian) / petrol
(East Pondian), since it seems to me that will go to some lengths to
avoid fouling engines with residues.  And it's available pretty much
universally, and relatively cheaply.
NO!  Highly flammable and contains a laundry list of things.  Good 
enough for cleaning
an engine of oil (with great care).  Oddly Kerosene (aka paraffin) can 
be had as (K1 crystal)
highly refined.  Again it can acquire impurities from the source but can 
also be purchased

in small containers for camp stoves and lamps.


Or am I wrong about it not leaving even trace residues?
There is what was called "white gas" that was pure petrol extracts 
without additives.

These days if you see it its for camp stoves and lights and not cheap.


Of course, anyone with distillation equipment could distil any of these
to get something with less residue.  But not everyone has chem-lab
glassware.
Or the temperature controls to not render unsafe(highly flammable) 
lighter gasses



Allison

/~\ The ASCII Mouse
\ / Ribbon Campaign
  X  Against HTML   mo...@rodents-montreal.org
/ \ Email!   7D C8 61 52 5D E7 2D 39  4E F1 31 3E E8 B3 27 4B

Re: Cleaning RK05 packs (Was: LGP-30 Memory Drum Update)

[allison]

On 1/5/17 8:36 AM, E. Groenenberg wrote:

We have a similar common name for it being 'brand spiritus'.

It's basically 90% - 92% alcohol, with the rest being methanol and water
and it's color is blue-ish.

Ed
--


In the past from the local print and painting supplier "De-natured alcohol"
Usually in a pint or gallon can (this is USA).  I also buy Lacquer thinner,
Acetone, Ethanol (99.4pure) and MEK in the same form all powerful
solvents and better than 99% pure.

Rubbing alcohol is ok save for its isopropanol plus water (either 70% or 
91%).
The latter 91% is safe for many uses and is water clear it leaves no 
residue

(however one must assure its dry after).

There is also Rubbing Alcohol that is ethanol plus water with an added 
denaturant

(toxic) to render it safe for skin use and not for drinking.

GC chemicals supplies two different residue free solvent cleaners.

My favorite head cleaner was banned in many places Xylene, takes curd
off like no tomorrow.  May melt the user too.

As to cleaning and repairing the drum... DO NOT TOUCH ANYTHING UNTIL
YOU ARE SURE of the process to be applied.  That applies to solvents, wipes,
and all.  Use gloves!  Test solvents near an edge or other area that is 
not critical.



Allison


Ik email, dus ik besta.
BTC : 1J5fajt8ptyZ2V1YURj3YJZhe5j3fJVSHN
LTC : LP2WuEmYPbpWUBqMFGJfdm7pdHEW7fKvDz

On Thu, January 5, 2017 14:22, Noel Chiappa wrote:

 > From: Klemens Krause

 > We clean our RK05 disks in a very robust way: with cheap burning
spirit
 > and paper towels. ... We rubbed away thick black traces from
occasional
 > head crashes and we never removed the oxide coating with this
torture.

I am about to get a large batch of RK05 packs, so I am interested in the
details of this.

First, what is 'burning spirit'? (I assume this is a straight translation
into English of some German term, but not knowing German... :-) After
poking
around with Google for a while (hampered no little by the fact that it's
the
name of a band, and also a term in World of Warcraft :-), it seems like it
might be acetone?

Noel

Re: Cleaning RK05 packs (Was: LGP-30 Memory Drum Update)

[Pete Lancashire]

>>you could test various solvents with a Q-tip to make sure they don't cause 
>>damage.

And a week later after the binder had decomposed what are you going to do ?

On Thu, Jan 5, 2017 at 9:05 AM, Jon Elson  wrote:
> On 01/05/2017 07:22 AM, Noel Chiappa wrote:
>>
>>  > From: Klemens Krause
>>
>>  > We clean our RK05 disks in a very robust way: with cheap burning
>> spirit
>>  > and paper towels. ... We rubbed away thick black traces from
>> occasional
>>  > head crashes and we never removed the oxide coating with this
>> torture.
>>
>> I am about to get a large batch of RK05 packs, so I am interested in the
>> details of this.
>>
>> First, what is 'burning spirit'? (I assume this is a straight translation
>> into English of some German term, but not knowing German... :-) After
>> poking
>> around with Google for a while (hampered no little by the fact that it's
>> the
>> name of a band, and also a term in World of Warcraft :-), it seems like it
>> might be acetone?
>>
> I'd be very careful with acetone, it tends to dissolve a lot of things, like
> maybe the binder in the coating.
> Rubbing alcohol (isopropyl) and pure ethanol are the things I've seen used
> to clean magnetic media.
> if there is a spot that is not actually used (maybe other parts of the
> gouged tracks) you could test various solvents with a Q-tip to make sure
> they don't cause damage.
>
> Jon
>

Re: Cleaning RK05 packs (Was: LGP-30 Memory Drum Update)

[Chuck Guzis]

On 01/05/2017 03:24 PM, David Bridgham wrote:

> This question of whether Simple Green was aluminum safe came up in
> the aircraft world a few years back and the answer turned out to be
> that some ingredient in there is mildly corrosive to aluminum.  Not
> badly so and if you managed to flush it off with water then no
> problem but if a bit of cleaner were to weep into a crack and not get
> get cleaned off then over time it might be a problem.  Not too long
> after that Simple Green came out with a new formulation, Simple Green
> Extreme or something like that, that *was* aluminum safe.  So look
> for the Simple Green that's sold for cleaning airplanes if you're
> cleaning around aluminum.


Freon TF works well on everything.  Too bad it's not available.

Is it still used for aircraft electronics?

--Chuck

Re: Cleaning RK05 packs (Was: LGP-30 Memory Drum Update)

[Lyle Bickley]

On Thu,  5 Jan 2017 08:22:05 -0500 (EST)
j...@mercury.lcs.mit.edu (Noel Chiappa) wrote:

> > From: Klemens Krause  
> 
> > We clean our RK05 disks in a very robust way: with cheap
> > burning spirit and paper towels. ... We rubbed away thick black
> > traces from occasional head crashes and we never removed the
> > oxide coating with this torture.  
> 
> I am about to get a large batch of RK05 packs, so I am interested in
> the details of this.
> 
> First, what is 'burning spirit'? (I assume this is a straight
> translation into English of some German term, but not knowing
> German... :-) After poking around with Google for a while (hampered
> no little by the fact that it's the name of a band, and also a term
> in World of Warcraft :-), it seems like it might be acetone?

I'm sure I've discussed cleaning packs on this list before, but here
goes again :)

I've cleaned a LOT of RL02 and RK05 packs. Both are relatively easy to
clean, but patience is definitely a virtue.

1) I clean the external surface of the pack with a damp cloth to
eliminate dirt and dust. Then I dry off any dampness with a clean, dry
cloth.

2) I open (unscrew or unclip depending on the model) the pack and
carefully set the screws (if any) in a clean (dust free) plastic box.

3) I examine the pack surface for crashes - and if there are visible
"hits" or "groves" in the pack, I discard it immediately.

4) Assuming the surface is good, I then use Lint Free Professional
Swabs saturated with Pure Anhydrous Isopropyl Alcohol (99.953% pure) to
clean the entire surface of the disk.

5) If there are any dirt buildup spots (NOT the result of a crash), I
use Lint Free Professional Chamois Swabs, saturated with the above
Alcohol, to gently clean up the spot. BTW, in my experience, this step
is rarely required.

6) After cleaning, I use a Lint Free Texwipe to GENTLY clean the entire
surface of any dust or other particulate.

6) I then clean all of the internal casing using Texwipe and the
above alcohol.

7) I re-assemble the disk and examine it for any dust particles with a
bright LED flashlight. If there are any visible dust particles, I use a
filtered air supply to blow away the dust.

NOTE: When replacing screws in packs, be super careful not to tighten
the screws too hard. Tightening too much can strip the plastic threads
and introduce plastic particulate on to the disk.

I've cleaned over 40 RL0x and RK05 packs using this method - and all
have subsequently worked perfectly.

NOTE: All of the above products are available online or at any
electronic supply house. The Pure Anhydrous Isopropyl Alcohol on the
container says: "For cleaning fiber optics, semi-conductors, contacts,
magnetic tape, medical equipment and other electronic devices. Zero
residue". Cost here in Silicon Valley is about $8 for 1 Litre.

Lyle
--
73AF6WS
Bickley Consulting West Inc.
http://bickleywest.com

"Black holes are where God is dividing by zero"

Re: Cleaning RK05 packs (Was: LGP-30 Memory Drum Update)

[David Bridgham]

On 01/05/2017 12:22 PM, j...@cimmeri.com wrote:
>
> It's very mild and has been aluminum safe for me (think, aluminum
> wheels on cars).

This question of whether Simple Green was aluminum safe came up in the
aircraft world a few years back and the answer turned out to be that
some ingredient in there is mildly corrosive to aluminum.  Not badly so
and if you managed to flush it off with water then no problem but if a
bit of cleaner were to weep into a crack and not get get cleaned off
then over time it might be a problem.  Not too long after that Simple
Green came out with a new formulation, Simple Green Extreme or something
like that, that *was* aluminum safe.  So look for the Simple Green
that's sold for cleaning airplanes if you're cleaning around aluminum.

Dave

Re: LC8-P (M8365) PDP8 printer interface schematics

[Mattis Lind]

2017-01-05 19:37 GMT+01:00 Ethan Dicks :

> On Thu, Jan 5, 2017 at 1:03 PM, Charles Dickman  wrote:
> > On Thu, Jan 5, 2017 at 10:15 AM, Mattis Lind 
> wrote:
> >> Is this the printset you are looking for?
> >>
> >> https://imgur.com/a/4uDS4
>
> Ah... MP-00075... I didn't see it on Bitsavers and Manx says "No
> copies are known to be online"
>

OK. I'll bring it home and will scan it sometime next week.

/Mattis


>
> http://manx-docs.org/details.php/1,6163
>
> >> https://imgur.com/a/mDvhD
>
> Nice.
>
> > Yes! That looks like it.
>
> Looks like it's 7 bits (D5-D11 -> P01-P07).
>
> -ethan
>

Re: LC8-P (M8365) PDP8 printer interface schematics

[Charles Dickman]

On Thu, Jan 5, 2017 at 1:37 PM, Ethan Dicks  wrote:
> On Thu, Jan 5, 2017 at 1:03 PM, Charles Dickman  wrote:
>> On Thu, Jan 5, 2017 at 10:15 AM, Mattis Lind  wrote:
>>> Is this the printset you are looking for?
>>>
>>> https://imgur.com/a/4uDS4

>
> Looks like it's 7 bits (D5-D11 -> P01-P07).

I noticed that when looking at the board last night. The OS/8 printer
handlers mask to 7 bits also. But its ASCII right, so that all you
should ever need.

-chuck

Re: LC8-P (M8365) PDP8 printer interface schematics

[Ethan Dicks]

On Thu, Jan 5, 2017 at 1:03 PM, Charles Dickman  wrote:
> On Thu, Jan 5, 2017 at 10:15 AM, Mattis Lind  wrote:
>> Is this the printset you are looking for?
>>
>> https://imgur.com/a/4uDS4

Ah... MP-00075... I didn't see it on Bitsavers and Manx says "No
copies are known to be online"

http://manx-docs.org/details.php/1,6163

>> https://imgur.com/a/mDvhD

Nice.

> Yes! That looks like it.

Looks like it's 7 bits (D5-D11 -> P01-P07).

-ethan

Re: Cleaning RK05 packs (Was: LGP-30 Memory Drum Update)

[Tony Duell]

On Thu, Jan 5, 2017 at 5:30 PM, Al Kossow  wrote:
>
>
> On 1/5/17 9:22 AM, j...@cimmeri.com wrote:
>
>> As Allison taught me, the oxide surface on platters / drums is just a form 
>> of inactive RUST.. and therefore, unaffected
>> by water (no, the water doesn't cause it to start rusting further).
>>
>
> The interface between the aluminum platter and the steel sector ring
> would be a really bad thing to get water into.
>

I seem to remember that at least some RK05 packs have a piece of foam inside the
hub (no idea what for, and it doesn't seem to be the Evil Foam that
turns to dust
or gunge). Get that soaked with water and you will have some interesting effects
when you spin up!

-tony

Re: Cleaning RK05 packs (Was: LGP-30 Memory Drum Update)

[Tony Duell]

> Another thing to watch out for is the two halves of some if not all
> were screwed together with self tapping screws. When you take
> them apart bit of plastic may come out of the holes or fall off the
> insides of the screw threads. That plastic if gets between the platter
> and head will not be to the heads advantage.

I seem to recall that one of the RK05 manuals warned that when re-fitting
said screws you should always put them in, turn them anticlockwise
until the threads engage and then tighten them clockwise. Just
screwing them in not only risks (as ever) stripping the thread in the
plastic housing, but also the action of cutting the new thread may
cause bits of plastic to break loose and they might (will!) end up
where they shouldn't

-tony

Re: LC8-P (M8365) PDP8 printer interface schematics

[Charles Dickman]

On Thu, Jan 5, 2017 at 10:15 AM, Mattis Lind  wrote:
> Is this the printset you are looking for?
>
> https://imgur.com/a/4uDS4
>
> https://imgur.com/a/mDvhD
>
> Sorry for top-posting. I hope the links are ok. Posting from the phone...
>

Yes! That looks like it.

Thanks,

-chuck

Re: Cleaning RK05 packs (Was: LGP-30 Memory Drum Update)

[j...@cimmeri.com]

On 1/5/2017 12:30 PM, Al Kossow wrote:


On 1/5/17 9:22 AM, j...@cimmeri.com wrote:


As Allison taught me, the oxide surface on platters / drums is just a form of 
inactive RUST.. and therefore, unaffected
by water (no, the water doesn't cause it to start rusting further).


The interface between the aluminum platter and the steel sector ring
would be a really bad thing to get water into.


Yeah, if you let it sit there long 
enough, but wiped dry (and let to sit to 
dry further), it's not going anywhere.


- J.

Re: Cleaning RK05 packs (Was: LGP-30 Memory Drum Update)

[j...@cimmeri.com]

It's very mild and has been aluminum 
safe for me (think, aluminum wheels on 
cars).


As Allison taught me, the oxide surface 
on platters / drums is just a form of 
inactive RUST.. and therefore, 
unaffected by water (no, the water 
doesn't cause it to start rusting further).


- J.

On 1/5/2017 12:21 PM, Al Kossow wrote:

http://simplegreen.com/downloads/SDS_EN-US_SimpleGreenAllPurposeCleaner.pdf

not something I would think of using on a disk surface

On 1/5/17 8:59 AM, Liam Proven wrote:

On 5 January 2017 at 17:11, j...@cimmeri.com  wrote:

- apply some Simple Green to a microfiber cloth


I may be the odd one out here, but what on Earth is "Simple Green?"

https://www.youtube.com/watch?v=TkZFuKHXa7w

Re: Cleaning RK05 packs (Was: LGP-30 Memory Drum Update)

[Al Kossow]

On 1/5/17 9:22 AM, j...@cimmeri.com wrote:

> As Allison taught me, the oxide surface on platters / drums is just a form of 
> inactive RUST.. and therefore, unaffected
> by water (no, the water doesn't cause it to start rusting further).
>

The interface between the aluminum platter and the steel sector ring
would be a really bad thing to get water into.

Re: Cleaning RK05 packs (Was: LGP-30 Memory Drum Update)

[Al Kossow]

http://simplegreen.com/downloads/SDS_EN-US_SimpleGreenAllPurposeCleaner.pdf

not something I would think of using on a disk surface

On 1/5/17 8:59 AM, Liam Proven wrote:
> On 5 January 2017 at 17:11, j...@cimmeri.com  wrote:
>> - apply some Simple Green to a microfiber cloth
> 
> 
> I may be the odd one out here, but what on Earth is "Simple Green?"
> 
> https://www.youtube.com/watch?v=TkZFuKHXa7w
> 

Re: LGP-30 Memory Drum Update

[j...@cimmeri.com]

On 1/5/2017 9:49 AM, Pete Lancashire wrote:

I would clean all the heads, and the surface with a soft cloth and give it a 
try.


A place I worked, a "soft dry cloth" unless it came out of a package
made by Texwipe or their competitors was known as "sand paper", if you
were caught using such you were fired on the spot and escorted out the
building. Same for paper towels.

Just my 2c's
-pete


I agree 100%.   I keep shaking my head 
in disbelief at these references to 
paper towels and other dry forms of 
sandpaper.


- J.

Re: Cleaning RK05 packs (Was: LGP-30 Memory Drum Update)

[j...@cimmeri.com]

On 1/5/2017 11:59 AM, Liam Proven wrote:

On 5 January 2017 at 17:11, j...@cimmeri.com  wrote:

- apply some Simple Green to a microfiber cloth


I may be the odd one out here, but what on Earth is "Simple Green?"

https://www.youtube.com/watch?v=TkZFuKHXa7w



Ever heard of Soylent Green?  Same 
stuff, but with more water added. :)


- J.

Re: LGP-30 Memory Drum Update

[Pete Lancashire]

Kimwipes ! That's the brand and products I could not remember. Just one
thing to add, there are many different types/variations, so be careful.

On Jan 5, 2017 7:15 AM, "Paul Koning"  wrote:

> On Thu, Jan 5, 2017 at 3:44 AM, Klemens Krause <
> kra...@informatik.uni-stuttgart.de> wrote:
>
> > ...
> > Cleaning the originally coated drum? I'm not sure how to do this.
> > We clean our RK05 disks in a very robust way: with cheap burning
> > spirit and paper towels. ...
> > The LGP-30 drum is much more singular, so we never tried to clean
> > the surface to avoid the risk of cleaning away the coating.
>
> I've seen an IBM field service tech clean an 1311 pack once (after the
> drive blew a gasket and sprayed hydraulic fluid everywhere).  He used
> Kimwipes soaked in isopropyl alcohol.  Since this was in college, I went to
> the chemistry department to get high purity (reagent grade) isopropyl
> alcohol for this job.
>
> A solvent sounds good, but I would avoid "burning spirit" or rubbing
> alcohol or other grocery store stuff since it probably has all manner of
> contaminants in it, some of which may leave crud on the surface.
>
> paul
>
>
>

Re: LGP-30 Memory Drum Update

[Pete Lancashire]

>>I would clean all the heads, and the surface with a soft cloth and give it a 
>>try.


A place I worked, a "soft dry cloth" unless it came out of a package
made by Texwipe or their competitors was known as "sand paper", if you
were caught using such you were fired on the spot and escorted out the
building. Same for paper towels.


Just my 2c's

-pete


On Thu, Jan 5, 2017 at 1:41 AM, Christian Corti
 wrote:
> On Wed, 4 Jan 2017, Cory Heisterkamp wrote:
>>
>> I'm far from an expert, but it certainly looks like an oxide coating to
>> me. I'm reminded of the folklore when IBM was developing the RAMAC and
>
>
> Yes, it is ferric oxide.
>
>> http://www.radar58.com/temp/drum.jpg
>> http://www.radar58.com/temp/drum2.jpg
>
>
> Hmm, your drum doesn't look to bad after all. In your case I would clean all
> the heads, and the surface with a soft cloth and give it a try. For basic
> testing you only need one data track plus the register and timing tracks.
>
> Christian
>

Re: Cleaning RK05 packs (Was: LGP-30 Memory Drum Update)

[Pete Lancashire]

DEC (branded, made by Texwipe) cleaning pads contained 99% isopropyl
alcohol. The most important part was being non abrasive.
I would consider using Texwipe or other brands of non abrasive
materials before I even though about a solvent.

I remember a disk being being cleaned with common paper towels, when
that person was done you could see the scratches all over the platter.

At one time the system I ran had over 200 packs in use.

Another thing to watch out for is the two halves of some if not all
were screwed together with self tapping screws. When you take
them apart bit of plastic may come out of the holes or fall off the
insides of the screw threads. That plastic if gets between the platter
and head will not be to the heads advantage.

BTW watch out for the filter cartridge seals disintegrating,

On Thu, Jan 5, 2017 at 5:55 AM, Pete Turnbull  wrote:
> On 05/01/2017 13:22, Noel Chiappa wrote:
>>
>> > From: Klemens Krause
>>
>> > We clean our RK05 disks in a very robust way: with cheap burning
>> spirit
>> > and paper towels. ... We rubbed away thick black traces from
>> occasional
>> > head crashes and we never removed the oxide coating with this
>> torture.
>
>
>> First, what is 'burning spirit'? (I assume this is a straight translation
>> into English of some German term, but not knowing German... :-) After
>> poking
>> around with Google for a while (hampered no little by the fact that it's
>> the
>> name of a band, and also a term in World of Warcraft :-), it seems like it
>> might be acetone?
>
>
> I'm sure it's not ! :-)  He'll mean the sort of alcohol used in a spirit
> burner.  The UK equivalent is "methylated spirit" - primarily ethanol but
> with a (un)healthy dose of methanol to make it unfit to drink (and hence
> exempt from excise duty) plus pyridine (and small amounts of other things)
> to give it an unpleasant taste and odour, and some methyl purple dye to make
> it obvious at a glance.  Denatured alcohol, in other words. I don't think
> the German (EU) version has the dye although it does contain IPA and MEK.
> For cleaning, because of that dye, isopropyl alcohol (IPA, isopropanol) is
> often a better choice in the UK.
>
> In the US, "rubbing alcohol" is mostly denatured ethanol (though "isopropyl
> rubbing alcohol" is mostly IPA), but always contains other chemicals as
> well.  Either should do for cleaning a disk.
>
> --
> Pete
> Pete Turnbull
>

Re: Cleaning RK05 packs (Was: LGP-30 Memory Drum Update)

[Pete Lancashire]

My error did mean to say 90% just got a bit too wound up with so many
suggestions that could destroy the coating.

On Jan 5, 2017 7:49 AM, "Al Kossow"  wrote:

> 91% IPA works fine.
> 99% is better though i'm skeptical it really is
>
> https://www.quora.com/When-is-70-isopropyl-rubbing-alcohol-better-than-91
>
>
>
> >> In the US, "rubbing alcohol" is mostly denatured ethanol (though
> "isopropyl rubbing alcohol" is mostly IPA), but always contains other
> chemicals as well.
>
> https://www.lewisu.edu/academics/biology/pdf/isopropanol_91.pdf
>
> IPA
> Water
>
>
>
>

Docs needed: DEC MXV11-B multi function module

[Jörg Hoppe]

Hi,

I've an DEC QBUS multifunction module here.

Type is MXV11-B M7195.

It does not boot into its ROM menu, despite I compared all the jumpers 
multiple time against documentation and a reference boards.


So it seems something in the ROM address logic is burnt.

Somebody has the FPMs schematics? I even can scan micro fiches.

Thanks,

Joerg

Re: Cleaning RK05 packs (Was: LGP-30 Memory Drum Update)

[E. Groenenberg]

We have a similar common name for it being 'brand spiritus'.

It's basically 90% - 92% alcohol, with the rest being methanol and water
and it's color is blue-ish.

Ed
--
Ik email, dus ik besta.
BTC : 1J5fajt8ptyZ2V1YURj3YJZhe5j3fJVSHN
LTC : LP2WuEmYPbpWUBqMFGJfdm7pdHEW7fKvDz

On Thu, January 5, 2017 14:22, Noel Chiappa wrote:
> > From: Klemens Krause
>
> > We clean our RK05 disks in a very robust way: with cheap burning
> spirit
> > and paper towels. ... We rubbed away thick black traces from
> occasional
> > head crashes and we never removed the oxide coating with this
> torture.
>
> I am about to get a large batch of RK05 packs, so I am interested in the
> details of this.
>
> First, what is 'burning spirit'? (I assume this is a straight translation
> into English of some German term, but not knowing German... :-) After
> poking
> around with Google for a while (hampered no little by the fact that it's
> the
> name of a band, and also a term in World of Warcraft :-), it seems like it
> might be acetone?
>
>   Noel
>

RE: Cleaning RK05 packs (Was: LGP-30 Memory Drum Update)

[Rick Bensene]

The method I've used very successfully for unknown packs is:

1) I first mount the pack in a drive that has a good absolute filter,
and has had the head load disabled, and spin it for a few hours.  If the
pack shows any sign of excessive vibration, it is probably no good or
requires more serious attention.   This process moves a bunch of air
through the pack, removing any loose dust.
2) I then take the pack apart, in a relatively dust-free space.  Inspect
the platter for any obvious damage that may make it unusable, such as
warping, mis-centered on hub (caused by being dropped), divots in the
platter surface or signs of serious head crash(e.g., oxide gone).   I
set the platter assembly on a lint-free cloth and cover with another
lint free cloth.
3) I first use a vacuum cleaner with a light brush attachment to vacuum
loose dust out of the pack case.  Then I use a sink with a sprayer head
and warm soapy water to thoroughly clean the plastic parts of the disk
pack, and rinse thoroughly with clear water.  I use dried compressed air
to blow out all the moisture, and then set the pack parts aside on a
lint-free cloth to dry out thoroughly, usually for 24 hours
4) I use 3M LCD monitor cleaning pads (which are lint-free by nature) to
wipe the platter surfaces to remove excess oxide and remaining dust.  I
use a light pressure.  Any areas that are clearly discolored get extra
treatment.  I wipe in a circular (spiral) motion from the hub outward to
the edge of the platters.  It's a little tedious from a handling
perspective, juggling the platter with one hand, and managing the wiping
with the other.  I end up using quite a few of the wipes, as they get
dirty pretty fast. 
5) I use a bright flashlight to spot any remaining dust and canned air
to dislodge any that I find.  If air doesn't work, then I use more wipes
to remove any that I can see.
6) Once over with canned air to blow off any remaining dust.
7) Quickly reassemble the patter into the pack casing 
8) Spin the pack again for  a few hours with no head load.
9) Cross fingers, put in a "live" drive, spin it up, and hope for no bad
noises.

Based on Klemens' method, this is probably being overly cautious, but
it's worked well for me. 

Rick Bensene

Re: Cleaning RK05 packs (Was: LGP-30 Memory Drum Update)

[j...@cimmeri.com]

The method I use for RL02 packs (not sure if similar), is:

- remove platter from pack
- rinse it down with tap water
- apply some Simple Green to a microfiber cloth
- wipe the entire platter with that cloth
- rinse by wiping with a 2nd cloth wet with distilled water
- let dry 24 hours

John

Re: Cleaning RK05 packs (Was: LGP-30 Memory Drum Update)

[Kyle Owen]

The cleaning procedure in the laboratory I used to work in for removing
organics from silicon wafers was typically acetone, then isopropanol, then
ethanol, then a deionized water rinse and nitrogen dry. We did use piranha
solution on occasion when it was particularly caked on (like really old
photoresist). When I cleaned an ST-4051 in the lab, I skipped the acetone.
That worked quite well; the drive worked just fine after that (and a
low-level format).

Kyle

Re: LC8-P (M8365) PDP8 printer interface schematics

[Al Kossow]

don't have them it turns out. mistook LC8-E for LC8-P


On 1/5/17 7:56 AM, Al Kossow wrote:
> we have them
> http://www.computerhistory.org/collections/catalog/102752995
> 
> i'll see about getting them on line by noon
> 

Re: Cleaning RK05 packs (Was: LGP-30 Memory Drum Update)

[Mouse]

>> In the US, "rubbing alcohol" is mostly denatured ethanol (though "isopropyl$

Interesting.  I don't think I've ever seen a bottle of "rubbing
alcohol" that was anything but isopropanol-and-water.  But I'm more
Canadian than US.

> I would suggest avoiding these blends of random chemicals made with no real $

Or, more precisely, with _different_ concern for purity.  For rubbing
alcohol you want to avoid biologically active contaminants, but
dissolved solids per se don't matter.  Here, you care about dissolved
solids but don't much care about things that might be biologically
active, as long as they evaporate without residue.

Which leads me to tentatively suggest gasoline (West Pondian) / petrol
(East Pondian), since it seems to me that will go to some lengths to
avoid fouling engines with residues.  And it's available pretty much
universally, and relatively cheaply.

Or am I wrong about it not leaving even trace residues?

Of course, anyone with distillation equipment could distil any of these
to get something with less residue.  But not everyone has chem-lab
glassware.

/~\ The ASCII Mouse
\ / Ribbon Campaign
 X  Against HTMLmo...@rodents-montreal.org
/ \ Email!   7D C8 61 52 5D E7 2D 39  4E F1 31 3E E8 B3 27 4B

Re: Cleaning RK05 packs (Was: LGP-30 Memory Drum Update)

[Al Kossow]

91% IPA works fine.
99% is better though i'm skeptical it really is

https://www.quora.com/When-is-70-isopropyl-rubbing-alcohol-better-than-91



>> In the US, "rubbing alcohol" is mostly denatured ethanol (though "isopropyl 
>> rubbing alcohol" is mostly IPA), but always contains other chemicals as well.

https://www.lewisu.edu/academics/biology/pdf/isopropanol_91.pdf

IPA
Water

Re: LC8-P (M8365) PDP8 printer interface schematics

[william degnan]

Most of what I have is related to the serial interfacing with the LA180.
Bill

Re: Cleaning RK05 packs (Was: LGP-30 Memory Drum Update)

[Paul Koning]

> On Jan 5, 2017, at 8:55 AM, Pete Turnbull  wrote:
> 
> On 05/01/2017 13:22, Noel Chiappa wrote:
>>> From: Klemens Krause
>> 
>>> We clean our RK05 disks in a very robust way: with cheap burning spirit
>>> and paper towels. ... We rubbed away thick black traces from occasional
>>> head crashes and we never removed the oxide coating with this torture.
> 
>> First, what is 'burning spirit'? (I assume this is a straight translation
>> into English of some German term, but not knowing German... :-) After poking
>> around with Google for a while (hampered no little by the fact that it's the
>> name of a band, and also a term in World of Warcraft :-), it seems like it
>> might be acetone?
> 
> I'm sure it's not ! :-)  He'll mean the sort of alcohol used in a spirit 
> burner.  The UK equivalent is "methylated spirit" - primarily ethanol but 
> with a (un)healthy dose of methanol to make it unfit to drink (and hence 
> exempt from excise duty) plus pyridine (and small amounts of other things) to 
> give it an unpleasant taste and odour, and some methyl purple dye to make it 
> obvious at a glance.  Denatured alcohol, in other words. I don't think the 
> German (EU) version has the dye although it does contain IPA and MEK.  For 
> cleaning, because of that dye, isopropyl alcohol (IPA, isopropanol) is often 
> a better choice in the UK.
> 
> In the US, "rubbing alcohol" is mostly denatured ethanol (though "isopropyl 
> rubbing alcohol" is mostly IPA), but always contains other chemicals as well. 
>  Either should do for cleaning a disk.

I recognized "burning spirit" by its Dutch analog, and yes, it means denatured 
ethanol.

I would suggest avoiding these blends of random chemicals made with no real 
concern for purity.  You need a liquid here that will evaporate cleanly, 
leaving behind neither oily residue nor solids.  I see no reason to believe 
that denatured alcohol or rubbing alcohol are made to those standards.

paul

Re: LC8-P (M8365) PDP8 printer interface schematics

[Mattis Lind]

Is this the printset you are looking for?

https://imgur.com/a/4uDS4

https://imgur.com/a/mDvhD

Sorry for top-posting. I hope the links are ok. Posting from the phone...


onsdag 4 januari 2017 skrev Charles Dickman :

> On Wed, Jan 4, 2017 at 7:08 AM, Christian Corti
> > wrote:
> > On Tue, 3 Jan 2017, Ethan Dicks wrote:
> >>
> >> On Tue, Jan 3, 2017 at 8:04 PM, Charles Dickman  > wrote:
> >>>
> >>> I am looking for schematics or any documentation for the LA180
> >>> interface for the PDP8/e. A scan would be great. I want to see if I
> >>> can use it to interface to a Centronics interface printer.
> >>
> >>
> >> I don't have the schematics (I do have an LC8-P somewhere), but I
> >> remember back in the day, people wanted to go the other way - feed a
> >> PC printer w/Centronics interface from a DEC interface.
> >
> >
> > It's not the other way, it's the same way ;-) (attatching a Centronics/PC
> > printer to a DEC interface)
>
> Yes, I want to connected an OKIDATA Microline82A to the PDP8/e.
>
> Looking at the LA180 manual's description of the LC8-P interface, it
> is pretty close to Centronics. I expect it is more than just a cable,
> though, because there is also an OMNIBUS Centronics printer interface
> board (LS8-E). That schematic is on bitsavers.
>
> I also have an LE8-E (M841), but that only provides 7 data bits to the
> printer.
>
> -chuck
>

Re: Cleaning RK05 packs (Was: LGP-30 Memory Drum Update)

[Al Kossow]

isopropyl alcohol works. TFE is better, if you have some stashed.

If you can find them anywhere, Texwipe made a plastic wand that looks like
a tongue depressor with a slit down the middle and a lint free sleeve
called the Texsleeve (tx300 sleeve, tx800 wand) that you would use to clean 
heads

Minor head crashes leave a tar-like residue that you need to remove. A pack 
inspector
is a handy thing to have (spinle with microscope and illuminator on the rack 
and pinion)
to look for surface damage.

On 1/5/17 5:22 AM, Noel Chiappa wrote:
> > From: Klemens Krause
> 
> > We clean our RK05 disks in a very robust way: with cheap burning spirit
> > and paper towels. ... We rubbed away thick black traces from occasional
> > head crashes and we never removed the oxide coating with this torture.
> 
> I am about to get a large batch of RK05 packs, so I am interested in the
> details of this.
> 
> First, what is 'burning spirit'? (I assume this is a straight translation
> into English of some German term, but not knowing German... :-) After poking
> around with Google for a while (hampered no little by the fact that it's the
> name of a band, and also a term in World of Warcraft :-), it seems like it
> might be acetone?
> 
>   Noel
> 

Re: Cleaning RK05 packs (Was: LGP-30 Memory Drum Update)

[Pete Turnbull]

On 05/01/2017 13:22, Noel Chiappa wrote:

> From: Klemens Krause

> We clean our RK05 disks in a very robust way: with cheap burning spirit
> and paper towels. ... We rubbed away thick black traces from occasional
> head crashes and we never removed the oxide coating with this torture.



First, what is 'burning spirit'? (I assume this is a straight translation
into English of some German term, but not knowing German... :-) After poking
around with Google for a while (hampered no little by the fact that it's the
name of a band, and also a term in World of Warcraft :-), it seems like it
might be acetone?


I'm sure it's not ! :-)  He'll mean the sort of alcohol used in a spirit 
burner.  The UK equivalent is "methylated spirit" - primarily ethanol 
but with a (un)healthy dose of methanol to make it unfit to drink (and 
hence exempt from excise duty) plus pyridine (and small amounts of other 
things) to give it an unpleasant taste and odour, and some methyl purple 
dye to make it obvious at a glance.  Denatured alcohol, in other words. 
I don't think the German (EU) version has the dye although it does 
contain IPA and MEK.  For cleaning, because of that dye, isopropyl 
alcohol (IPA, isopropanol) is often a better choice in the UK.


In the US, "rubbing alcohol" is mostly denatured ethanol (though 
"isopropyl rubbing alcohol" is mostly IPA), but always contains other 
chemicals as well.  Either should do for cleaning a disk.


--
Pete
Pete Turnbull

Re: LGP-30 Memory Drum Update

[Cory Heisterkamp]

On Thu, Jan 5, 2017 at 3:44 AM, Klemens Krause <
kra...@informatik.uni-stuttgart.de> wrote:

>
>>
>> http://www.radar58.com/temp/drum.jpg
>> http://www.radar58.com/temp/drum2.jpg
>>
>
> From the fotos your drum looks better than our working one, with
> the exception of the large engraving on the right side. Especially
> the left part, were the registers are located looks very good.
> On our drum are also some dark traces without showing the Al of
> the drum.
>

That is encouraging news. The engraving on the right appears to be machined
into the drum as it's much deeper than the oxide finish and completely
uniform. I'm not sure what purpose it serves, if any. I've adjusted the 7
heads along the left side as one was just making contact.


> I can't see the 1" long spots you're speaking from. How much is
> "a couple"?
>

There's a total of 3 such marks on the drum not visible in the photo, 2
caused at some point in the past as the heads that caused them were
relocated from those tracks, and one short scratch caused by me after
having removed all but the last head bar assembly and checking for drag. It
seems each bar had at least one, if not more, heads in contact with the
drum, which I was not expecting.


> In your place I would try to revive the drum track by track:
> Looking for the registers, find out if the timing tracks S1 to S3
> are ok, then looking for tracks 0 to 3 in which the loader,
> program 10.4 sits, then track 63, which is used for booting the
> loader. Even if you have only some more tracks you can run simple
> hand coded programs on your machine. Just think at a KIM-1 single
> board computer with 256 bytes of RAM: People had fun with it! :-)
>

I think this is a good idea. I hadn't planned on running anything other
than hand coded programs, and having at least several tracks functional
will help me in troubleshooting the rest of the machine. I can then
transition to a solid state mem later.


>
> Cleaning the originally coated drum? I'm not sure how to do this.
> We clean our RK05 disks in a very robust way: with cheap burning
> spirit and paper towels. They have similar technology: Al-base
> with iron oxide coating. We rubbed away thick black traces from
> occasional head crashes and we never removed the oxide coating
> with this torture. In every case the disks were 100% error free
> after this. But in this case the risk ist low: the disks had errors
> and if we ever would have washed away the oxide coating, we have
> enough other disks to experiment with other solvents.
> The LGP-30 drum is much more singular, so we never tried to clean
> the surface to avoid the risk of cleaning away the coating.
>

I used a clean, soft, paper towel without any solvent or liquid and gently
ran it from left to right while rotating the drum. This picked up a little
fine oxide, but whoever serviced the drum last did an excellent job of
sealing it. After they replaced the plastic cover they ran strips of
electrical tape (which was still firmly stuck) down both sides. The air
filter is also still present on the machine which is a good sign.  -C

Cleaning RK05 packs (Was: LGP-30 Memory Drum Update)

[Noel Chiappa]

> From: Klemens Krause

> We clean our RK05 disks in a very robust way: with cheap burning spirit
> and paper towels. ... We rubbed away thick black traces from occasional
> head crashes and we never removed the oxide coating with this torture.

I am about to get a large batch of RK05 packs, so I am interested in the
details of this.

First, what is 'burning spirit'? (I assume this is a straight translation
into English of some German term, but not knowing German... :-) After poking
around with Google for a while (hampered no little by the fact that it's the
name of a band, and also a term in World of Warcraft :-), it seems like it
might be acetone?

Noel

Re: LGP-30 Memory Drum Update

[Klemens Krause]

On Wed, 4 Jan 2017, Cory Heisterkamp wrote:



On Jan 4, 2017, at 1:02 PM, allison wrote:


On 1/4/17 1:06 PM, Jon Elson wrote:



Previous messages suggested the LGP-30 drum was plated with nickel.


Nope. I ever wrote about iron oxide.



I'm far from an expert, but it certainly looks like an oxide coating
to me. I'm reminded of the folklore when IBM was developing the RAMAC


Yes, I agree.
...

In that case it was easy to apply...just spin up the disc and pour!


Good idea, this should work with the drum too.


There are a couple of 1" long spots where the coating was scraped away and the heads 
relocated. Given what I've read about the Control Data badged LGP-30's, this was likely a 
refurb sold in the 60's. The replacement heads certainly support that. Below are some 
pics of my drum; the tonewheel clock generator can be seen at the far right. The groove 
just to the left of that leaving a single band in the mag material is too perfect to be a 
goof, but at the 0.4" head offset spacing, is too narrow to contain more than one 
track.  -C

http://www.radar58.com/temp/drum.jpg
http://www.radar58.com/temp/drum2.jpg



From the fotos your drum looks better than our working one, with

the exception of the large engraving on the right side. Especially
the left part, were the registers are located looks very good.
On our drum are also some dark traces without showing the Al of
the drum.
I can't see the 1" long spots you're speaking from. How much is
"a couple"?
In your place I would try to revive the drum track by track:
Looking for the registers, find out if the timing tracks S1 to S3
are ok, then looking for tracks 0 to 3 in which the loader,
program 10.4 sits, then track 63, which is used for booting the
loader. Even if you have only some more tracks you can run simple
hand coded programs on your machine. Just think at a KIM-1 single
board computer with 256 bytes of RAM: People had fun with it! :-)

Cleaning the originally coated drum? I'm not sure how to do this.
We clean our RK05 disks in a very robust way: with cheap burning
spirit and paper towels. They have similar technology: Al-base
with iron oxide coating. We rubbed away thick black traces from
occasional head crashes and we never removed the oxide coating
with this torture. In every case the disks were 100% error free
after this. But in this case the risk ist low: the disks had errors
and if we ever would have washed away the oxide coating, we have
enough other disks to experiment with other solvents.
The LGP-30 drum is much more singular, so we never tried to clean
the surface to avoid the risk of cleaning away the coating.

Klemens

(p.s.: got the book, an interesting lecture)



--

klemens krause
Stuttgarter KompetenzZentrum fyr Minimal- & Retrocomputing.
http://computermuseum.informatik.uni-stuttgart.de

Re: LGP-30 Memory Drum Update

[Christian Corti]

On Wed, 4 Jan 2017, Cory Heisterkamp wrote:
I'm far from an expert, but it certainly looks like an oxide coating to 
me. I'm reminded of the folklore when IBM was developing the RAMAC and


Yes, it is ferric oxide.


http://www.radar58.com/temp/drum.jpg
http://www.radar58.com/temp/drum2.jpg


Hmm, your drum doesn't look to bad after all. In your case I would clean 
all the heads, and the surface with a soft cloth and give it a try. For 
basic testing you only need one data track plus the register and timing 
tracks.


Christian