Hello Rich
My unit is solid state.
The ac is secure.
When a record is put on the turntable and the needle makes contact there is a " pop" sound and a humming sound through speakers that is not affected when the volume knob is turned.

My 1967 mm1 had static while adjusting volume that would end when desired volume level was reached. Last use, the sound quit and has nothing. All other functions work properly except sound. Could this be a simple fuse or more complex as volume control unit? Any suggestions / prior experience with pr...