Hamurabi Focal source

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. -tony