F4 had blown when I was getting 24v.??? I replaced it and q4, soldering both pins of q4 temporarily.?? It's possible the "one good" inseption clip was not.???
I'm just glad to be over that for now...
Hi again.
?From the above measurements, it looks like Q4 is bad (open collector?)?
But later it is said the -12.6 rail came good.
Intermittent connections around Q4, as someone (forget who) mentioned
happened due to a bad power transistor heatsink mounted socket, that I
too in the past have had troubles with, in other makers kit where they
were used for convenience.? Or other bad connection issue(s).
It would be worth checking F4 and it's holder or clips if PCB mounted,
and their soldering on the PCB too perhaps.
The + and - 100V rails don't seem too far out, for now.
The -24V episode on the -12V rail, might have damaged (for example)
flood gun filaments in the CRT (if your instrument has a storage tube.)?
There was I recall, one other who said they had a tube with burnt out
flood gun filaments.?? Or was that with F4 removed, and you saw that on
the transformer side of F4?
?From over 40 years of fault finding and repair experience in a wide
range of electronic products, not just instrumentation, the weirdest
symptoms often have a really simple root cause!
Regards to All.
Dave B.
--
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