>> Could this be caps reforming, gassed tubes, or the amp turning into an
>> oscillator (TPTG!)?
>
>Most common would be tubes and/or open grid resistors on the
>tubes.
>
Not Invented Here syndrome?
- For the curious, it might be interesting to measure the resonance of
the "grounded"-grid with a dipmeter. If, perchance, the resonance of the
grid is lower than the resonance in the plate/anode circuitry, the grid
looks inductive at the anode resonant freq., a feedback path exists, and
the VHF TPTG oscillator circuit is unfortunately extant -- even though
it does not appear on the circuit diagram.
> ...
- R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K,
www.vcnet.com/measures.
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