Unit came into FSC with complaint of no record or playback,erase OK both channels bad. Power supply check showed correct B+ voltagesfor amplifier circuits. Muting transistors Q103, 203 were not turningoff. Q303 (muting driver) Q103, Q203 all OK. Foun
Intermittent high frequency oscillation. Once started, theonly way to stop it was to engage record mode and return to play. Problemoccurred only in play mode.