I have a 1200W PSU to repair, not sure what's wrong with it, bought as-is. So I haven't powered it with mains yet.
So nothing visibly wrong so far, (but lots of hidden stuff too) looking around inside the mains filter stage is fine, the dual rectifiers, PFC caps/mosfets/diodes seem fine in circuit. The main PWM mosfets seem fine. The various inductors/trans. I've checked so far seem fine to a DMM. I've applied 10Vdc in, and everywhere I checked so far seems about as I'd expect 10V to do. I haven't found the low-voltage supply area yet, I'll do that now (or play StarCraft 2 campaign on brutal).
There's a relay that's right before the 2 main PFC caps. In circuit it's switch side reads as 18ohm, it should be open, I'll have to pull that. It's a 2-sided PCB, maybe thats more for inrush current and I'm reading 18ohm from a current limiting thing, and then the relay would turn on to just close the switch after a few moments. Just remembered that trick from teardowns.
I have a current limiter lightblub setup, but I won't have an auto-transformer until June/july.
I haven't checked anything on output side yet. How safe should it be to turn it on now ?
There's a lot of daughter boards with various fets/controllers, and a 5V and 12V VRM sections for final output reg. I don't want to turn it on if I'm only doing more damage. Lot of work tho to pull and check the daughter board stuff at random.