I just got a Metallica with an older cointaker shaker motor in it. It was horrible, make a racket, clanky as hell. I adjusted the weights every way possible, installed a PVM, still janky.

The issues was 4-5 mm of play on the motor shaft itself. Whenever the motor went off, the shaft slammed back and forth inside the motor housing.

I took it apart, and hammered the pictured end in, with both weights, loose on the shaft to keep it straight/even. This removed most of the play in the shaft. I then put 2 washers on the motor side of the bracket mount.

It now works properly without all the racket. If nothing else worked for you, might give this a try.

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