Silvertone 1484 oscillating. help!

http://www.freeinfosociety.com/electronics/schematics/audio/silvertone1484.pdf

working on one of these silver tones. but having a really hard time with it.
damn thing just starts oscillating when I turn up the volume. its a very high frequency in the or close to the Mhz.

it seems to be coming from the first or second gainstage, and the treble control effects the frequency of the oscillation. replaced the cathode bypass caps, that improved the situation, but didn't fix it.
the grid resistors in the first stage test fine, as does the grid to ground resisitor.
any suggestions would be greatly appreciated.
-hm

My usual practice with Silvertone amps is to go through and measure every resistor. A lot of them usually drift high, causing all manner of problems. But the good part is that since they drift high, you can measure them in-circuit.

Yeah. I think that the resistors were 25% tolerance when installed at the factory. They are like little brown twigs with watercolor paint on them. Also check to make sure that all of the 1/4" sleeves and pot legs are connected to chassis. Some metal-metal chemistry develops there depending on how much incense was burned in little jimmy's bedroom.
Mike

50% and the thing will still run.
tubes are the loosest thing on earth, outside of Lyndsey Lohan before the reduction.

wiggle the tubes around in the sockets, install a grounding plate brass,(copper, reynolds if you have to.
foil) under all panel controls.