Looking for Silent 700 printhead

Charles charlesmorris800 at centurytel.net
Sat May 4 20:53:52 CDT 2019

I have two Silent 700 terminals (model 745) that I bought quite a few years 
ago (nonworking). Couldn't find a schematic. Last week I just happened to 
search for one - and found a complete service manual with theory of 
operation and full schematics! So I got them on the workbench.

The more worn one wouldn't print anything on the paper but was otherwise 
working. I found that the nylon printhead pressure adjustment wheel had 
split and fallen off the solenoid shaft into the case, along with the 
pressure spring. Then it would print, but I promptly discovered that the 
printhead has several "dots" missing in a pattern that could not be 
accounted for by the driver circuitry. I confirmed it by swapping the 
printhead from the other one, and now it prints perfectly. So at least I 
have one working now :)

The second one in half-duplex mode will only beep (Ctrl-G), CR and LF in 
half-duplex mode, so I know the keyboard is alive and there is power.
But it otherwise won't move the carriage forwards (including space), or 
print any characters at all.

Before I go to the trouble of diagnosis and repair, does anyone have a good 
printhead, or know where I can find one?
No point in fixing it if the characters won't be printing properly when I'm 


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