I have a gigabyte MA785GMT-UD2H with an AMD Phenom II X4 965, a radeon 5770, and an OCZ 600w power supply. My computer has been running just fine for over a year. I decide to open it up and reorganize the cables around - unplugged everything, ran some cables around the other side and such.. plugged everything back in, no video or post. I've gone through the checklist - cleared the CMOS, took out video card and used onboard graphics, used each RAM separately, unplugged EVERYTHING except the 8pin and 24pin connectors to the mobo and the CPU fan .. I'm getting power - the fan is spinning and the LED on my heatsink fan turns on, and when I had my video card still in it was spinning. I've checked all connections to make sure they are secure. No short circuits that I know of. No short or long beeps of any kind. Any help would be appreciated.. thanks!!
Do you have a way to check the voltage from your psu like a volt meter? I remember years ago I installed a psu and the 110/220 switch was in the middle instead of all the way to the 110 side and it gave me simptoms like that till I saw the problem. Maybe swap it with a good one to see. Then maybe switch out the cpu with another if voltage is OK. It maybe the board if it's not the memory, (I doubt that all sticks would go bad at once) or the psu or the cpu.
So just an update - I tried everything i possibly could and ended up RMA'ing my motherboard - got it back today, everything is fine except one thing it's not recognizing my radeon 5770 and i have to use my onboard video. I can't find it under device manager ot CPUID - i checked that it is securely in and checked the power cord to it - could this be a power issue?
Btw I had the same problem today with my MA785. I was adding new hardware from Newegg and when I tested everything back together everything was working upstairs. I put the case cover back on and got downstairs and no post!
Brought the rig back upstairs, went through everything (which was very frustrating as it always is when this happens to any of us). After getting down to the barebones, w/ just 1 mem stick and nothing connected to the mobo, I realized that the RAILS power connector had been loose and came out!!! If any of you are old school and built PCs when there were no rails you sometimes forget now that you even have to connect them darn things.
Symptom: MA785 starting, fan starts, motherboard wouldn't post (no PC speaker beep, no video).
Resolution: Check power connectors-- the rails connector came out in my case.