[flywheel]

Originally Posted by Uncle Bulgaria

I would recommend taking it a step at a time, checking the DC conditions first, as I mentioned above. Replacing components that aren't broken isn't good practice. It can introduce other faults, and it's inefficient.

The metal cans are usually expected to be the most reliable, as it seems they survive most readily in many types of equipment even long after their design life.

My Ferrograph's metal cans were no exception, with only one being found leaky and unresponsive to reforming on initial repair. I then changed one of the PSU ones when it was the motorboating culprit, a symptom that arose after I'd been using it daily for a few months.

Having said that, I had to replace a lot of my resistors and capacitors in the amplifier stage as they were largely out of tolerance. If you unsolder one leg you can measure them reasonably accurately.

C2 is probably just fine - Hunt's have a poor reputation because we're finding some of their components have failed, decades after their designers would have expected them to be obsolete. On mine, C2 is a motor capacitor, 0.75µF 450V. I haven't changed it - it's probably a paper in oil type, and reliable, without the failure modes of waxed paper or wet electrolytic. If you don't notice any motor problems it's likely fine.

The motor capacitor is filled with a grease-like* compound that's almost certainly the now-banned polychlorinated biphenyl. The Visconol branded caps also contain a more oil-like substance that's likely to be a version of the same. So, if it's still working, it's best to leave where it is!

*I once opened one up out of curiosity, but now wish I hadn't.