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I've checked and replaced a few caps in the -150V, 100V, and 300V supplies in my Tek 575.
Now these supplies are all in spec for voltage and ripple. One cap seems to have an elevated ESR, so I'll probably replace it soon too.

I've also replaced all four 2000 uF caps in the 12 V supply. The 150 uF cap in this section seems to be OK. What voltages and ripple should I expect here? I didn't see any specs on the schematic.

The curve tracer seems to work, but the out and back I-V curves do not lie on top of each other and the whole family of I-V curves seems to "wobble" a bit on the screen.

Does this sound familiar? Any ideas?

I'm wondering if I have some excessive ripple somewhere else. Any ideas?

I'll try and make a YouTube video, to demonstrate what I'm talking about.

Thanks,
-Scott

The curve tracer seems to work, but the out and back I-V curves do not lie

on

top of each other and the whole family of I-V curves seems to "wobble" a

bit

on the screen.

Does this sound familiar? Any ideas?

That sounds about right. It depends on the collector base capacitance, but
you can end up with "looping" where this capacitance has a significant
effect, particularly with medium to high power transistors. In fact Tek
recommended a method for estimating this capacitance; you add external
capacitance and when the loop doubles, the external value about equals the
collector base capacitance.

The wobble is mainly visual - if you reduce the number of base steps, you
will see that the wobble disappears every other step.

Also switch to the higher step generator rate to reduce trace flicker.

Craig