I've just built a new PC with all-new components:
abit IP35 PRO motherboard
Antec Neo HE 500 power supply
Intel Core2 Duo E6850
2GB Corsair TWIN2X2048-6400C4 memory
GeForce 7900 GS OC PCI Express graphics card
When I try to start with this configuration I get the dreaded 8.2. POST code (Enable ATX power supply). The red 3VSB LED is lit, but not the green VCC LED. I cleared CMOS, but it didn't make any difference.
Suspecting the PS I switched it for a known-to-be-good 480W PS (an Antec True 480) from a working computer. This time when I try to start the PC, all the fans (case, CPU, graphics card) turn on briefly and then stop and POST code 9.9. is displayed (Complete power off sequence). After about four seconds the fans cycle on and then off again. This repeats until I turn off the power.
I tried an older 350W PS. This time the system boots and I can get into the BIOS. I set the memory voltage to 2.1v (recommended for the Corsair memory) from the default 1.8v just in case this was the problem. The system boots every time with this PS.
I changed back to the 480W PS, but the problem is still there - the fans cycle and I get the 9.9. POST code.
I tried the 500W Antec NEO HE PS one more time, but that just gets me back to the 8.2. POST code.
I am going to return for an axchange the 500W Antec NEO HE power supply, but is this the problem?
Could it be the motherboard?
Why does an older, lower power PS (not an Antec) cause it to work OK?
I hope someone out there can help since my fingers are getting sore from fiddling with all those connectors.