The European models of the Polysix all had pre-installed 3-wire power cords. The service manual also gives only schematics for two different 3-wire setups. But in general: having voltage against ground on the chassis is a bad thing, regardless if the problem goes away with a grounded plug. This should be fixed at the root of the problem.
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Re: [PolySix] Polysix frying mixer channels
2018-08-31 by Malte Rogacki