) writes:
Thanks All,

No problem with the set, just trying to play around with the UHF tuner.
It appears to have an input for 18VDC and line for the AFT. The TV
had some other problems and I removed the tuner to see if I could do
anything with it.

I don't see anything on the O'scope out of it but will try a scanner at
44 MHz to see if I can hear any stations. Guess I will need a wideband
FM scanner.

If you're talking about putting the scope at the output of the UHF
tuner, that's not likely to show anything.

As someone pointed out, those tuners used a diode mixer, so you not
only see no gain, but there is a loss between the input and the output.
The signal is going to be very weak with that sort of tuner. I'm not
sure when active tuners kicked in, but even those won't have too much
of an output.

Better to make sure the oscillator is oscillating. Use the scanner
to tune in the tuner's oscillator signal. After that, either the
diode is good, or it's not. Beyond that, if there's a problem it's
not an active component, because you've just accounted for them
all.

Michael