ODEC/ Data 100/ LC8-P (M8365) PDP8 printer interface schematics

Jon Elson elson at pico-systems.com
Tue Jan 31 11:14:19 CST 2017

On 01/31/2017 06:45 AM, David Gesswein wrote:
> On Sun, Jan 29, 2017 at 10:27:49PM -0600, Jon Elson wrote:
>> I think we had an Odec chain printer that another group gave us to
>> use on our VAX.  I hacked it up to shut off the chain motor when it
>> wasn't printing, and then restart it when print data came in.
> Mine has a switch to select that and control codes to turn it off and on.
I seem to remember it turned out VERY easy to do this.  I'm 
guessing my unit had control codes, but we didn't want to 
hack the VAX software, so I rigged a one-shot to do it instead.
> Mine has the same path.  The manual has a procedure for adjusting the guides
> for ribbon foldover problems.  It came with multistrike film ribbons so
> hopefully they won't be a pain. Looks like they used 35mm film reels for
> the ribbon. Were you using normal inked cloth?
Yes, inked cloth ribbons.  They were cheap, but ran properly 
for a short time before they started skewing.  You could 
either replace the ribbon after 1/10th of the print life was 
exhausted or keep fiddling with the tracking to try to get 
to 50% usage.

At home I had a HUGE Honeywell 300 LPM drum printer with a 
weird character set and a totally nonstandard interface.
it also used a folded ribbon scheme, with 2" wide ribbons.  
That one NEVER had ribbon tracking issues, you could run the 
ribbon until you could see through it, and it still tracked 
fine.  I never knew WHY the tracking on the Odec was so 
finicky.  Possibly just we were using crummy ribbons that 
were not made with the right cloth.  I don't think we ever 
bought ribbons for it, the people who gave it to us gave us 
a box of new ribbons.
>   Good to know its a nice
> printer otherwise. Pretty slow for a chain printer, only 125 LPM. Haven't
> figured out if its a real difference or board jumpers between it and the
> 1423 200 LPM.
OK, ours was also slow, but it had lower and upper case.  I 
suspect a different chain with upper case only would print 
twice as fast.


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