- Jul 28, 2004
- 2,618
- 5
- 81
I've got a really weird problem with a GA-MA785G-UD3H board that has been working fine for many years.
When it's on, the computer can be reset and it will reboot just fine, but if power is cut, the motherboard refuses to POST unless I clear the CMOS. Here is what happens:
1. Motherboard POSTs, works completely fine
2. Computer is shut off
3. Power button is hit to turn it back on - no POST, no beeps. CPU fan spins, no keyboard lights.
4. The only way it will POST is if you wait nearly 30 minutes with the CMOS battery out and the power cut.
I don't know what it is about this board but it takes at least 30 minutes to clear the CMOS making troubleshooting this very difficult. There is a CLR CMOS pin that the manual says jumping for 4 seconds is supposed to clear the CMOS, but even leaving those pins shorted for over 3 minutes doesn't clear anything.
While it's in its "refuse to POST" state, I remove all peripherals (USB), take out all memory, or leave only one stick in, change the order of the sticks, remove all PCI / E devices, remove all disk drives, etc. Makes no difference. It will not POST until a significant period of time has gone by and the CMOS has been cleared of its configuration.
I do have a PC speaker hooked up and it does beep when it POSTs successfully so I'm certain the PC speaker is working. Also I bought a brand new eVGA power supply at 450 watts, with no extra load of disk drives or anything, it exhibits the same symptoms. Refuses to boot again until CMOS is cleared.
Finally I managed to flash the BIOS to the latest one on Gigabyte's website (from F4 to F5g, a beta BIOS) and still the same issue.
Any help is appreciated.
Mods: Sorry if this does not go here, I didn't see a general troubleshooting thread, please move it if it fits better elsewhere.
When it's on, the computer can be reset and it will reboot just fine, but if power is cut, the motherboard refuses to POST unless I clear the CMOS. Here is what happens:
1. Motherboard POSTs, works completely fine
2. Computer is shut off
3. Power button is hit to turn it back on - no POST, no beeps. CPU fan spins, no keyboard lights.
4. The only way it will POST is if you wait nearly 30 minutes with the CMOS battery out and the power cut.
I don't know what it is about this board but it takes at least 30 minutes to clear the CMOS making troubleshooting this very difficult. There is a CLR CMOS pin that the manual says jumping for 4 seconds is supposed to clear the CMOS, but even leaving those pins shorted for over 3 minutes doesn't clear anything.
While it's in its "refuse to POST" state, I remove all peripherals (USB), take out all memory, or leave only one stick in, change the order of the sticks, remove all PCI / E devices, remove all disk drives, etc. Makes no difference. It will not POST until a significant period of time has gone by and the CMOS has been cleared of its configuration.
I do have a PC speaker hooked up and it does beep when it POSTs successfully so I'm certain the PC speaker is working. Also I bought a brand new eVGA power supply at 450 watts, with no extra load of disk drives or anything, it exhibits the same symptoms. Refuses to boot again until CMOS is cleared.
Finally I managed to flash the BIOS to the latest one on Gigabyte's website (from F4 to F5g, a beta BIOS) and still the same issue.
Any help is appreciated.
Mods: Sorry if this does not go here, I didn't see a general troubleshooting thread, please move it if it fits better elsewhere.