[Hallicrafters] HT-32B Quit Working

[David C. Hallam]

My HT-32B quit working.  I used it one day and when I turned it on the next
day there was no output on any band in any mode.  With full RF drive and CW
mode, there is some indication on the output meter but my Bird wattmeter
just gives a little wiggle in the 250-watt position.  I checked the usual
things, HV and LV, OK.  The 12BY7 driver tested OK and I tried substitution
of a different tube.  Looked at the VFO output on my scope and it looked
normal.  The tube in the third mixer tested OK and I tried substitution.

Since problems are on all bands, I discounted problems in the second mixer.
Checking the first mixer and sideband switching oscillator, I noticed a big
drop in oscillator output on the scope when switching from 4.05 MC to 13.95
MC. (My scope is a 50 mHz scope.) However, the output from the mixer
remained relatively constant regardless of the oscillator in use.

The speech amplifiers seemed to be working OK, as was the carrier
oscillator.  Using a two-tone test oscillator, the output pattern from the
beam modulator on the scope was what I expected.  I tried substitution of
another 7360 with no change.

Now comes the part I don't understand.  With the scope on the grid of the 9
MC amplifier tube, I see the normal "double bubble" RF pattern from the
two-tone signal.  However, if I disconnect the sideband generator cable from
the main chassis and look at the output (plate side of the 9 MC amplifier)
of the SS generator on the scope, I see the two-tone audio pattern on the
scope not the "double bubble" RF pattern.  I have tried replacing the tube
with no change.  Resistance readings on all the SS generator tubes appear to
be normal.

Any ideas?

David C. Hallam
KC2JD