New PSU, comp refuses to turn on

[BobA]

I have installed a Seasonic M12 500, and after hooking everything up, there is no activity, not even the large always on fan comes on. However, when I do the 4 to 5 pin short test, the fan does come on.

The 4 pin and 24 pin connectors are properly seated. One of the two SATA drives is connected from the Seasonic-supplied SATA cable to 5-pin connector on the PSU. The other SATA is connected to one of the 6 pin connectors on the PSU. This is a cable from my former ANTEC PSU. I'm using it instead of the Seasonic cable because I cannot dislodge the ANTEC's SATA cable from the HDD.

Finally, the CD, FDD and case fan all connect through one 6 pin connector to the PSU. This is the former ANTEC cable.

When I press the computer's on button, nothing happens. The always on fan does not turn.

It seems as if the PSU is not getting a signal from the computer power switch/motherboard, but yet I know that this signal path works with the ANTEC, and it is not loose.

This particular Seasonic is an RMA from my retailer, and I hate to send it back.

Anybody got any ideas?

-Bob

 

[evongugg]

You may have a bad power switch. Try shorting the pins with a screwdriver.

 

[BobA]

Have you tried it without the Antec cable plugged in. The pin againgment of the connectors on the PSU side may be diffrent.

The motherboard 4 pin and 24 pin are from the Seasonic M12 500 of course, the Antec cables are to the peripherals. The peripheral cables would have no effect on the PSU firing up. As I mentioned, the Seasonic fan will turn by jumping pins 4 and 5 of the 24 pin connector. I contacted Seasonic customer support, and I suggested to them there might be some sort of incompatibility with the PSU and my Chaintech VFN4 motherboard. They couldn't offer any solution, but did offfer an RMA. It already is an RMA replacement from my retailer.

I was thinking that the Seasonic might be incompatible with my Tripp-Lite dual conversion UPS, but I bypassed it and no difference.

I cannot think of any solution, so what I have decided to do is sit on it until I do my next build (after Vista SP1). I'll have to make sure I get a known compatible motherboard for the PSU, but that shouldn't be too hard because Seasonic is likely to sell a lot more of them between now and then.

I bought the Seasonic as a replacement for my Antec SP 500. So far the Antec is OK. And as long as it doesn't crap out before I do my next build, I'm OK.

It was a disapointment getting two Seasonics in a row that won't work, but as I said, I don't think there is anything wrong with the Seasonics, because I can get the fan to turn by jumping pins, but it won't turn or fire up when installed on my motherboard.

-Bob