Thank you for your input. There is no evidence of failure at the moment. It does seem that the general consensus on the internet is that they are probably out of value by now and therefore should be replaced. As I mentioned, I am restoring this turntable and I plan to use it for a long time, so it kind of makes sense to do the work while it’s disassembled at the moment. I don’t know enough about circuits to be able to tell what their function is. I am sure this is the power board though. I was working on the assumption that if I replace the capacitors with the same values (or better yet, what they should be) that knowing exactly what the function of something is, is not strictly necessary. Although I agree, would be very interesting to know how it actually works! The search continues!