I started to grind out the old batteries, got distracted, and by the time I got back to it the new one arrived. I put it into the Keithley 213 and the error at power on was gone after the first POR when I cleared it with software. Taking it out and reinstalling it gives a power on error the first time and once cleared, you can power it on and off without error. With the old DS1213c the unit wouldn't pass POST so it looks like it is working, maybe?
The reason I say 'maybe' is that after pressing the calibrate button and writing new gain and offset values (without error) they reset to default after powering off and on. No errors as when I remove it, just default values as if the calibrate button wasn't pressed before writing the values. I checked the button with an ohm meter and all is well. This isn't a huge deal since you can't operate it except from software and I can send the offset and gain setting for the reference voltage I need with each command. I don't know if I will be able to build step waveforms in memory as they are voltage only, I think, without offset and gain. I actually doubt I would ever use it in that mode anyway but the calibration failure bugs me. It could still be operator error or maybe the DS1213c isn't keeping the voltage up when powered off?
The 213 is a +/- 0 to 10V reference source at 10ma. It seems really stable, as good as any 6.5 digit reference source I have, and once warmed up I get little if any flicker on the lowest digit of my HP 3457a.
Thanks