On Tue, 23 Feb 2016 22:46:21 -0500, legg wrote:

If you've got UF4007s, then what are you waiting for? Polyester film
caps in low voltage circuitry are the last things to suspect.

Even if there are bits flaking off them?? That's the case here!

Obviously a professional technician just wants to get each unit fixed as
soon as possible so as to get on to the next one and maximise his income.
But I'm just a hobbyist and my motivations are not at all the same. Of
course I'd like to get this up and running, but if I don't *learn*
something from the experience, then it'll be next to worthless AFAIC. So
you might see it as screwing around to run these side-by-side diode tests
from your perspective, but I really don't. This unit is beyond economic
repair, but I'm still working on it - for a little while longer anyway -
whereas a professional service person could not afford the time on what
he would see as a basket-case.