SB-610 follow up

[Steve]

Several of you guys offered advice last month when I asked for help with
an SB-610 monitor scope. Thought I'd post a follow to let you know how
it turned out.

I replaced the high-voltage filter caps, C604, C605 and C606. Didn't
help the trace much though. But it was probably wise to replace them for
their age as well as to protect the transformer secondary from leakage
current. Those transformers are hard to find!

I had checked all the voltages previously and replaced several resistors
that had went bonkers. All the voltages except pins 1, 2, 3, and 12 on
the CRT that is. Those voltages are over 1000 volts, which is as high as
my meter measures.

A few days ago I tumbled onto the idea of using a variac to get those
voltages down into a measurable range. I set the input to 60vac, made
some measurements and quickly found 330K 1/2w resistor R506 open.
Replacing it brought the trace to life.

I understand that electrolytic capacitors deteriorate with the passing
of years, hence their replacement. Wonder what happens to the tubular,
disc and mica caps that are used in the SB-610 over 30 years?

My thanks to the several of you who offered advice, this is a very
helpful group!

73,

Steve
K8JQ

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