Unresponsive 9100B

[dfnr2]

Hello,

I recently acquired an HP9100B which was working before shipping, but on arrival does not respond. The fuses are intact, and I can hear the power supply humming on power up, but there is no CRT output, and I cannot activate the error light (for example, by STOP-CLEAR-/ to get a divde by 0 error.) The register label backlight also doesn't light, but apparently did not light before shipping, when the calculator otherwise worked.

I have Tony Duell's excellent schematics, which I'm grateful for. I also have a service manual, and plan to go through it, but it seems a bit short on theory and detail. I'm not in position to swap out boards.

My plan, once I am able to get some time at the bench, is to start out by checking the power supply voltages, clocks, and move on from there. However, since apparently something changed during shipping, I'd be interested in any suggestions that would help inform a smarter investigation. I am hopeful it's not the CRT, as I would expect the error light to come on. Any suggestions would be very much appreciated.

Dave