From: Russ Miller
E-mail: rmiller@parallaxinc.com
Check out HP's site manual listing site: http://www.tmo.hp.com/tmo/Db/manual/
I recieved a 9100A/B service manual from HP a few months ago. P/N 09100-90034. It covers trouble shooting, power supplies, and video (I think). No repair information for logic circuits (They say unplug and return to factory for repair), but the troubleshooting section may help localize the problem. Email me if you have specific questions.