Folks, I am just about to tear my hair out. I've built 15 or more systems in the last 20 yrs, and I'm a former ET in Navy.
On my second Gigabyte board. I RMA'd the first. Here's the symptoms:
With pwr switch jumpered. The system will only come on with the 8 pin ATX connectors unplugged. With that set up, the machine will run but not post, no beeps, no video, etc. If either, or both, 2x4 ATX connector is in, the system will power up for about 3 seconds then shut down. If the power on switch is not jumpered, the system will not turn on at all.
So, one question I have is whether the pwr switch is a momentary sw that could be bad.
Same results with the following attempted:
Chg'd power supplies,
Chg'd out memory,
Tried using just one stick of memory,
Tried different processor,
Tried with all peripherals unplugged,
Guys, I really need some help, because I absolutely refuse to let a machine beat me.
Here's the components:
550 w pwr supply
Gigabyte MA785 UD3H
AMD AM2+ 6000 black edition
EVGA 8800GT video
turns out it was the front panel pwr sw. The idea of being momentary took hold, and I came up with a quick check. I placed a small thread underneath the jumper, then jumpered the pwr pins on the motherboard. I turned on power on back of power supply, waited about 1/2 sec, then pulled the jumper out using the thread. Next thing you know, post city and boot.
Just kind of weird that the problem manifested right at a rebuild of this machine. Very odd.
Anyway, off to Radio Shack for a switch.
Thx for the reply earlier. I hope this might help someone in the future.
was your cpu fan spinning at its maximum speed? i have the exact same problem as you and a pc shop is looking at it. ive changed everything that i can imagine, besides the motherboard, which i think is the culprit. my mobo is a GA-MA770-UD3
Yes, the cpu fan and rear fan powered offf the motherboard both spun at high speed. Keep in mind that with my problem the power would shut off after 3-4 seconds. So, it makes sense that the front panel pwr switch was hanging up. It is suppose to be a momentary on switch to simply iniate the post and boot sequence. If that pwr is constant, the motherboard never knows to begin post and boot.
You might try the the trick I described with the jumper and thread. If it works and machine posts, your front panel pwr switch is bad. I hope this helps.
Is this, like, a forum rule or something - if so, I've violated, and won't again - I often give people here my email, as I'd rather that than they PM me - I'm a really old fart , and sometimes forget to 'unhide' the right column to look for PMs for three weeks or two months at a time, depending on how busy I am elsewise! Dunno that I'd ever post a phone # though, really don't want phone calls at three AM from South African datacenters...