AMC Record Player Crazy Loud Humming

I have an AMC DS-10 console record player that has a crazy loud deep hum. I’ve replaced all three vacuums. The TT is grounded inside the receiver but I even went as far as to ground it once again into the outlet in the wall with a three prong plug in. The humming stops when I remove either one of the 50C5 tubes. The humming doesn’t happen until I plug in the phono power receptacle. I’ve fought with this thing for over a week now and I am pretty much an amateur and would just like some advice as to what to try or test next. I can’t attach a photo at the moment but can do so later.


There ought to be a simple Grounding Wire emanating from either the tonearm or the turntable. Screw the wire onto/into the receiver or phono stage's grounding screw...which should be on the back panel. With any luck, silence will instantly prevail.

This is what I originally thought but could not find a ground wire or a hook up for the ground wire on the back panel. However what I am pretty sure to be the ground wire, running from the phono to the receiver, I detached and reconnected it to a different part of the TT and still got nothing. But all in all could not find an obvious grounding “screw” which I thought was weird. 

Those 50C5 tubes were used in old electronic designs that used series heaters directly run from the AC mains and can be extremely dangerous. My understanding is that some of the transformerless designs could have a live chassis! You're asking for trouble modifying anything in there.