Hello all,
I also got now my 617 from EBAY.
When it came, it showed in all ranges Overflow - ok, for Ohm's this would be fine if connections are open - ;-) ...
A check of all pats of the device showed, that U307, Q303, Q305 and Q307 on the electrometer board where blown.
U307 is easy to fix, it is an LM337. But the transistors Q303, Q305 and Q307 are MPS-U60 types from good old Motorola.
I have looked at different mfg sites of discrete bipolar transistors and found out, that MJD340 (NPN),
MJD350 (PNP) will fit mostly to the parameters of the original MPS-U10 / MPS-U60 types, but the parameter "Emitter−Base Voltage" is only 3V with the Motrola type. The Transistors specified with 6V here.
Does anybody have an Idea, if MJD340 and MJD350 will be fine replacement for MPS-U10 / MPS-U60 - yes, thy are SMD, , but I think, could be adapted ...
Kind regards
Guido