I have a carcass of one of these multimeters if you need any more parts. I have that transistor in it.
Thanks. I did just find some of the proper transistor on eBay.
Just paid too much for an 8120A out of nostalgia for the 8100B, which broke 25 years ago and I didn't have the ability to fix then. Not much left of it though: circuit board, some of the frame.
Does any of the power supply work? If this transistor doesn't fix it I will be looking for somebody else with a working 8100 who can do some measurements.
EDIT: Just remembered, a couple years before it had the fault I could not fix, it lost it's power supply due to a failure of Q6 - a little TO-92 near that RCA part which I replaced with a 2n3904 or 6. How come I can remember that and not names?
Yes, Q6 is a 2N3906! I think that is part of the 15v rail. I isolated the -18v with the procedure in the service manual, and am still having problems. I tried replacing Q2 and Q3.
EDIT2: I have a Micronta 22-174B I can plug it into if you want a comparison hFE.
That would be quite helpful actually. If you have a chance please let me know. That is actually the same meter I am using. I have a Fluke 87V and a bunch of bench meters, and some analog meters. But only the Micronta has the hFE. It's actually a decent meter, save for the slow autoranging and likely "CAT Negative One" rating
If this turns into a repair thread I will start a new thread. Would like to post some pictures anyway.
Thanks.