I tried mu metal shielding but to no avail.? Yes rotating the transformer is tedious, but it solves the problem.? There is quite a variation from R-4C to R-4C
and I have? no idea why.? That said they are all bad from my perspective, just some worse than others.
I would first have to determine if this is actually a problem in my R4C but I doubt I would go to the trouble of reorienting the transformer. I have a large piece of mumetal somewhere that we used in our magnetic disk test equipment. It
would be interesting to see if a piece of that between the transformer and the PTO would help.