[Boatanchors] BC-312/342 audio problem

[Ian Wilson]

I've recapped this radio, apart from the AGC decoupling
caps in the RF/mixer cans.

Have replaced a few underperforming VT-86's and aligned
the IF stages and the RF stages on 40m.

Everything is basically working. However, the audio is poor,
with a lot of high-frequency noise and distortion above about
75% on the volume control. Both MVC and AVC are like this
but behave somewhat differently. Voltages on the RF gain
pot and the various grids all check out OK as I vary the gain
in the two modes.

The audio is poor both on AM and SSB. I should look for an
audio signal source, I guess, to check out the audio stages on
their own. Am using an audio output transformer of unknown
impedance ratios to a decent speaker.

Anything obvious I should look for?

73, ian K3IMW