Hamurabi Focal source
ard at p850ug1.demon.co.uk
Wed Mar 31 13:26:21 CDT 2010
> If you get stuck, I can sure help. I recently restored an HP 2748B
> optical reader (500 CPS) and built an RS232 interface for it so that
I restored one of thoise a couple of years back -- or actually the -A
version which has simpler electronics (but much the same functionality).
I got the HP9800 interface for it (HP11202 Opt A01 IIRC) on E-bay. As you
probably know the outputs of the 2748 are pilled up to 12V, but through
10k resisotrs, whcih means they will feed the 180R/390R-terminated TTL
inputs of the 11202 with no prolems. Of course the -B model that you have
has clamp diodes anyway so you can force the outputs to TTL levels by
jumpering 2 pins on the connector.
What was wrong with yous? Mine had a bad mbearing in the magnetic clutch.
T oreplace that I had to make special tools to press the clutch unit
aprt and put it togetehr again. The ball race itself was a standard size
and I had no problems getting one. Of course I also had to make the
alignment mandrel to ge the clutch parts centred up wehn I put the motor
unit back on.
There are a few photos in my flickr account (tony_duell) of the internals
of the read head and of taking the motor/clutch apart.
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