A little help? Problems with PSU.

Grim666 · 5 Dec 2009 at 20:56

I'm trying to work out if I'm doing something wrong or if there are any more tests I can do. Last week I couldn't get my PC to power up at all so after trying a couple of things I switched the PSU from another machine and the PC worked fine. So I bought a new Corsair HX 750W to replace the original HX620W that seems to be dead. Delivered yesterday, installed today and I can't get it to power up either. I've switched cables, tried different plug sockets and tried disconnecting everything but the motherboard.

From what I've read on here and elsewhere Corsair are supposed to be the best there is. Have I just been unlucky to get a faulty one straight after the first one died? Can I disconnect it from the motherboard and switch it on without damaging it and should the fan spin?

Any advice appreciated.

RJC · 5 Dec 2009 at 20:58

Link out pins 13 & 14 on the main 24 pin ATX connector, this will enable the psu, I would connect a fan to one of the molex connectors.

Grim666 · 6 Dec 2009 at 14:22

I went out and bought a PSU tester and now I'm confused. PSU comes on, all the readings seem to be right. I've also tried it with the old PSU and it seems to be working as well.

For some reason when its connected to any part of the PC nothing happens. Its not like it tries to start but can't supply enough power, it just doesn't power up at all.

The old PSU has been working for 2 years in this PC and an old Hyper 580W PSU from another machine has works fine. Any ideas?

Grim666 · 6 Dec 2009 at 16:55

A friend suggested the motherboard may have a power surge and the PSU is detecting it. Could he be right? Would a PSU simply not power up at all if it was a mobo problem?