[MrFixr55]

Did you have a cap in series with the signal tracer probe? Is there a diode in series with the probe? If yes to both then you may have to turn down the gain of the tracer. If no cap, then you may have been overdriving the tracer with B+

Ohm the secondary. It should be quite low, about 8 Ohm. There is a good possibility that it is open. If you connect the tracer to either diode plate of the detector / 1st AF Amp Tube (6R7), i suspect that the sound level will be low. Isolating the ground on the probe with a large cap (like 0.1uF, connect ground side of the probe to the green wire on the IF Out trans and probe the brown wire with a diode in the circuit. The signal should be quite loud.

Note that there are 2 100pF caps, 39A and 39B, each between ground and either side of R43. These are likely mica and, although rare for them to fail, it may still be possible. Excessive leakage of either cap will definitely lower the volume and AVC signal.

Hope this helps.