System fails to start (most times)

[StarTech]

The system has EPOX 8K7A+, 512MB, 5 HD drives, CDRW, U2W controller, video, netcard, modem,Enermax whisper 320W PS.

A few days back the power company had outage and since then I have had problems starting box. Most times wont start, with port80 LEDs coming up at FF or C1, but not going thru any sequence. Last nite it would not start at all. This morning it started at first try.

Background tips:
- Two weeks ago I noticed the back fan in PS was not turning, so I ordered/replaced it.
- One day before the power outage I replaced flat cables for scsi and IDE array with round cables.

I would like opinions on what is the most likely cause of the failure? PS? MB? Cables? Memory? Other?

 

[AKA]

Intermittent problems powering it on are likely the power supply. If you remove the power cord from back of power supply and reconnect it.. does it always power on then?

Cables inside the computer on ide and scsi devices wouldn't have anything to do with it not powering on.. so you can rule that out.
Unless its trying to power on? When you go to power it.. does it kick for a sec then immediately go off?

 

[StarTech]

Yesterday I was turning off the PS switch for a few seconds, then back on and try, and it was failing consistently. But I did not leave it off for a significant time. Did not try to pull plug out but switch should be equivalent.

When it fails, the P80 LEDs dont appear to sequence at all. Some times come up at FF, other at C1. I may have seen other values also. But there is no sequence/stop pattern I can notice.