Rca u-10

[dtvmcdonald]

Yesterday I got an RC U-10 radio-phono, ostensibly to use
as amplifier chassis for a TRK12. But in any case I want
to get it working properly.

I looked at the chassis and a couple of paper caps had
late 60s Mylar replacements. The people I got it from said
it worked, though how the phono could have with no insulation
on the leads to the pickup and the motor loose and flopping around,
I don't know.

I tried the radio only on a dim bulb, Variac and B+ meter, and
it works fine. A recap is pending.

But two questions: the pickup is a crystal one, It runs into the
volume control of a standard AA-5 style 2 stage audio setup (it does
have a power transformer). Its probably bad, though does generate
up to 0.1 volt (into 1 megohm) if the needle is thumped. Do replacements
for these exist?

Second question is how the phono-radio-TV switch works. It has three
positions and the radio signal appears at high volume in two of them
and low volume in the other. The description of the switch on the
schematic is opaque. Does anybody know how this works? I don't
relish the task of tracing it out.

I have zero experience with old phonos. Mine is with radios and TVs.

Doug McDonald