[Hallicrafters] sr-400 cyclone II oscillates

[Walt Cates]

Hear is the setup:
any band,
PLATE and LOAD preset per manual,
RF LEVEL and MIC GAIN fully ccw,
OPERATION set to MOX,
FUNCTION is in USB,

Now I move the FUNCTION switch to tune. Then I adjust the PRESELECTOR to the appropriate place relevant to the band sellected. The rig immediately goes into oscillation, plate I pegs out. The rig has to be shut down to once the oscillation begins. The oscillation even continues into the REC position of the OPERATION switch.

Walt