22 Oct
2003
22 Oct
'03
11:36 a.m.
Hi all,
I am in the process of restoring a 96 column impact printer sold by the
digital group around 1977. (See my progress at:
http://members.cox.net/oldcomp3/dgp/dgprinter.shtml)
The first question I have is about the print head: Does anyone have any
idea what, if anything, is the proper lubricant for a print head? What
little lubricant I found on the heads felt like it might be a silicone
grease of some kind. I have no idea if this was original lubricant or
not. Labels I have found on other printers warn against oiling the print
head, stating that the heads are lifetime oiled at time of manufacture.
Next, I wonder if anyone on the list might have any information on the
printer itself, which appears to have been manufactured by Practical
Automation Inc., of Shelton Conn., or on the digital group electronics.
Any ideas?
-Bryan
22 Oct
22 Oct
11:49 a.m.
excellent job in restoring this printer!
I would have two suggestions for you.
for lubricant use a very fine graphite material.
If you need to, use tungsten wire for the print
hammer pins themselves. Also replacements would
not rust.
Jim
Bryan Blackburn wrote:
2:14 p.m.
At 04:49 PM 10/22/03 -0700, you wrote:
excellent job in restoring this printer!
I would have two suggestions for you.
for lubricant use a very fine graphite material.
I've had great luck using liquid graphite lock lubricant. The solvent
evaporates and leaves only the graphite. The graphite particles in the
liquid lube are much finer than those used in the powered stuff. The
powdered stuff is useless for everything that I've ever tested it for,
including lubricating locks! There several good things about the liquid
graphite. First, it doesn't cause drag the way that liquid lubes (oil,
grease) do. And since it's dry it doesn't attract and hold dirt and sand (a
real problem here in Florida!). And in a case such as your's, it will
tolerate high temperatures. The biggest problem is that no one seems to
make or sell it any more! I had a can of it but it developed a leak and all
leaked away. When I tried to buy more I was surprised to find that no one
carried it and I was told that no one still made it. I finally found an old
locksmith that can me a can of the stuff. Now I guard it with my life! A
LITTLE bit of this stuff goes a long ways. Use it EXTREMELY sparingly.
If you need to, use tungsten wire for the print
hammer pins themselves. Also replacements would
not rust.
If you can't find the right size wire, try piano wire (from a hobby
shop) or drill rod (industrial suppliers). Drill rod is annealed (soft) but
it can easily be hardened after you cut it to length. Drill rod is
available in MANY diameters and it's size is very uniform and accurate.
IIIRC it's available in both oil-hardening and water-hardening types.
Joe
Jim
Bryan Blackburn wrote:
23 Oct
23 Oct
7:14 a.m.
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8:15 a.m.
At 08:14 PM 10/23/03 +0100, you wrote:
No, I haven't but I should. It would probably work as well. I just don't
like the dry powdered graphite. It's a joke as far as I'm concerned.
(or at least that's what it's called
I've
had great luck using liquid graphite lock lubricant. The solvent
evaporates and leaves only the graphite. The graphite particles in the
Have you tried 'dry film lubricant' over here, Electrolube (used to?) make it). It's
similar, but with fine
PTFE particles. The carrier evapourates (it's not really a solvent,
neither for graphite or PTFE), and leaves PTFE on the surface. Like the
'liquid graphite', the result is non-sticky, doesn't attract dust, and
seems to be good for many light machine parts.
I beleive the original pins were tungsten wire in some printheads. The
stuff certainly behaves like tungsten...
I wouldn't be surprised. Tungstan has a lot of properties that would
make it usefull in print heads; very hard so less wear, heavy weight for
inertia, and it withstands high tempertures well. But I'll be the
manufacturers hate it, it's hard to machine and expensive.
Joe
If you
need to, use tungsten wire for the print
hammer pins themselves. Also replacements would
not rust.
If you can't find the right size wire, try piano wire (from a hobby
shop) or drill rod (industrial suppliers). Drill rod is annealed (soft) but
-tony
24 Oct
24 Oct
6:20 a.m.
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23 Oct
23 Oct
8:33 a.m.
New subject: TRS-80 model 4 serial question.
I'm installing a serial board into my model 4, there is a 4-pin connector
on it, right next to the 20 pin cable that goes from the cpu board to the
serial board, what connects to the 4-pin connector...
AND
does anyone have a PDF of the serial installation instructions? and/ or
a PDF of the service manual for the model 4?
1:19 p.m.
New subject: TRS-80 model 4 serial question.
on 23/10/03 4:33 PM, Geoff Reed wrote:
does anyone have a PDF of the serial installation
instructions? and/ or
a PDF of the service manual for the model 4?
Geoff,
the manual you want is probably here:
http://www2.asub.arknet.edu/wade/hardware.htm
Arlen Michaels
24 Oct
24 Oct
6:22 a.m.
New subject: TRS-80 model 4 serial question.
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23 Oct
23 Oct
3:47 p.m.
Thanks to everyone for the comments and suggestions.
I have something very similar, which was made for motorcycle control
cables, called Dri Slide. It is molybdenum disulfide based dry film
lubricant, withstands high pressure and temp. I think I will give that a
try.
I've had
great luck using liquid graphite lock lubricant. The solvent
evaporates and leaves only the graphite. The graphite particles in the
Have you tried 'dry film lubricant' (or at least that's what it's called
over here, Electrolube (used to?) make it). It's similar, but with fine
PTFE particles. The carrier evapourates (it's not really a solvent, >>If you need to, use tungsten wire for the
print
>>hammer pins themselves. Also replacements would
>>not rust.
>
> If you can't find the right size wire, try piano wire (from a hobby
>shop) or drill rod (industrial suppliers). Drill rod is annealed (soft) but
For my project, at least, it is a moot point. I have already repaired
the print pin with a pin robbed from another old printer. The most
difficult aspect of the repair was finding a long enough wire of proper
diameter. Brazing the wire to the solenoid was a skill I had to learn
just for this repair, and was not as hard as I had expected. I spent a
lot of time practicing on scrap metal with various heat sources before
repairing the print hammer.
Thanks again for the suggestions.
-Bryan
12:59 a.m.
Bryan Blackburn wrote:
Hi all,
I am in the process of restoring a 96 column impact printer sold by the
digital group around 1977. (See my progress at:
http://members.cox.net/oldcomp3/dgp/dgprinter.shtml)
The first question I have is about the print head: Does anyone have any
idea what, if anything, is the proper lubricant for a print head? What
little lubricant I found on the heads felt like it might be a silicone
grease of some kind. I have no idea if this was original lubricant or
not. Labels I have found on other printers warn against oiling the print
head, stating that the heads are lifetime oiled at time of manufacture.
Next, I wonder if anyone on the list might have any information on the
printer itself, which appears to have been manufactured by Practical
Automation Inc., of Shelton Conn., or on the digital group electronics.
Any ideas?
-Bryan
Shelton? That's in my neck of the woods...
--
--- Dave Woyciesjes
--- ICQ# 905818
26 Oct
26 Oct
7:04 p.m.
New subject: More photos: digital group impact printer restoration
If anyone is interested, I have added another page to the photos of my
digital group printer restoration. (Is anyone interested? :)
The original page,
Page 1: http://members.cox.net/oldcomp3/dgp/dgprinter.shtml
and the new photos,
Page 2: http://members.cox.net/oldcomp3/dgp/dgprinter2.shtml
-Bryan
27 Oct
27 Oct
2:39 a.m.
New subject: More photos: digital group impact printer restoration
On Mon, 27 Oct 2003, Bryan Blackburn wrote:
If anyone is interested, I have added another page to
the photos of my
digital group printer restoration. (Is anyone interested? :)
Yes! This is amazing work!
The documenting of the project while you go is very cool as well.
--
Sellam Ismail Vintage Computer Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger http://www.vintage.org
[ Old computing resources for business || Buy/Sell/Trade Vintage Computers ]
[ and academia at www.VintageTech.com || at http://marketplace.vintage.org ]
28 Oct
28 Oct
5:26 a.m.
New subject: More photos: digital group impact printer restoration
-----Original Message-----
From: cctalk-bounces(a)classiccmp.org
[mailto:cctalk-bounces@classiccmp.org]On Behalf Of Vintage Computer
Festival
Sent: 27 October 2003 16:40
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: More photos: digital group impact printer restoration
On Mon, 27 Oct 2003, Bryan Blackburn wrote:
You beat me to saying that - the before and after pictures are excellent!
It's difficult to believe it's the same print mechanism.....
cheers
--
adrian/witchy
www.binarydinosaurs.co.uk - the online computer museum
www.snakebiteandblack.co.uk - ex-monthly gothic shenanigans :o(
If anyone is interested, I have added another
page to the photos of my
digital group printer restoration. (Is anyone interested? :)
Yes! This is amazing work!
The documenting of the project while you go is very cool as well.
7726
days inactive
7732
days old
13 comments
9 participants
participants (9)
-
ard＠p850ug1.demon.co.uk -
arlen＠acm.org -
dwoyciesjes＠comcast.net -
geoffr＠zipcon.net -
jwstephens＠msm.umr.edu -
oldcomp＠cox.net -
rigdonj＠cfl.rr.com -
vcf＠siconic.com -
witchy＠binarydinosaurs.co.uk