Pete,

Thanks for the reply. I just bought a signal generator and should be
receiving it shortly so I can test it.

I did check the LO and it works fine.

I checked all voltages as listed on the service manual and they match
fine except the voltages on the discriminator tube. They list as 0.25
volts on pins 3 and 5 (I believe) but they are actually showing as
-0.25V. I don't know if that has anything to do with it. Could it be
one of the capacitors in the discriminator coil unit?

Will keep looking....

Thanks.
--
Elias


" Uncle Peter" wrote in message news:0AySc.13831$Yf6.7407@lakeread03...
"Mazur" wrote in message
om...
All,

I just finishing re-capping a Hallicrafters SX-42 I bought recently.
Thanks Phil for an excelent web site (http://antiqueradio.org/) and
big help.

If the FM is dead, two things too check as a start: First, see if you
can force a 10.7 MHz signal through the IF stages. In the SX-42, the
AM 455kHz IF amps also double as 10.7 MHz IF stages and
utilize 455kHz and 10.7 MHz IF cans in series. On FM, there are
two additional 10.7 IF (limiter stages) before the FM detector as
well. You could also inject audio at the output of the FM detector
to verify that the audio paths are working in that mode.
If the IF stages are all working and passing a 10.7 MHz signal,
I'd verify that the LO is working on the FM band.

This should be an easy problem to isolate using signal injection
or signal tracing.

Pete