[Diabolical Artificer]

"One technique to use looking for a short is to apply some current limited supply" That's what I would normally do Dave, power up on a CLPSU, check to see what getting hot either by touch, freezer spray or a fancy thermal camera, but this beasty is complicated having four or five different inter-dependant PSU's, though only one or two seem to be at fault, that and it's supposed to get hot it being valved.

This is also tricky in that as soon as the time delay triggers the relay, the main fuse blows, game over, so my approach has been to check every cap etc around where I think the fault could be and disconnect various parts of the circuit, power up and see if I guessed right. I've gone through a box of fuses but luckily I have a box NOS 3A Russian jobbies- tried a circuit breaker, but it wasn't quick enough.

This short as far as I can see if basically a couple of lengths of wire joining two bits of BR's, but I'm damned if I can find the short by traditional means, however Chris's idea of using a lamp to limit current is a good idea and thinking about it I could use my 500v 3A supply that has a CCS mode. I keep having a go, get nowhere, have a think, then have another go. I'll get there and hopefully be able to tell the saga of the 585A in the long hall over a few cups of mead one day after the kiddies have gone to bed.....

Andy.