I'm trying to repair this RCA 45 record player. When I started it had loud hum even with the volume control all the way down. I recapped and now no hum when the volume control is all the way down but as soon as you turn the volume up you get music with lots of hum in it. Subbed tubes 35W4 and 50C5 and no luck. The 12AV6 checks OK. This is a Model 6EY1 it is very similar to the 45EY models but not exactly the same.

The motor mounting hardware should be grounded with the chassis. There should be a connection at the mute switch that goes to the chassis. I think there is a 3 pin connector from the switch to the amp. 2 wires are from the cartridge, 1 is the ground.

Could also be that if the wiring is all ok, the cartridge has gone bad and has completely opened up, though if shielding is adequate, this doesn't always introduce hum. ...But if the audio is very quiet and there's hum in it, then you may either have bad wiring or a bad cartridge.

T.