PC won't POST until I clear CMOS?

[SteveL]

I've got a very strange problem with one of my PCs, and I thought some of the knowlegable peeps in here might have seen something similar, or be able to suggest what's wrong.

It's a Gigabyte 7VAXP Ultra motherboard, and it appears to have a bit of a problem with the saved CMOS information.

We had a power cut, and when the power came back on, one of my PCs wouldn't boot.

The only way I can get this machine to boot is to clear CMOS. Once I've done this, it boots, takes me into the BIOS to save CMOS information and then it continues to boot into Windows. I can the use it perfectly normally. If I shut it down, then it won't boot, until I clear CMOS, then it behaves perfectly again.

So at the moment, it goes like this.

Power machine on, save CMOS, continue to boot, work normally.

Shut machine down

Power machine on. Fails to POST. No beeps, No display. HDDs spin up, all fans on, but nothing happens.

Clear CMOS.

Power machine on, save CMOS, continue to boot, work normally.

Shut machine down

Power machine on. Fails to POST. No beeps, No display. HDDs spin up, all fans on, but nothing happens.

etc. etc.

(This board has no "Clear CMOS" jumper, so each "Clear CMOS" means taking the CMOS battery out and leaving it overnight!)

I've seen this sort of thing reported a few times, but I can't find anyone who actually fixed this problem.

Any ideas?

Steve

[-ChEM-]

try a new bios chip, it requires a special tool but apart from that its a rip-it-out-plonk-it-in job so it shouldnt cost much

cheapest way is probably to get hold of a new bios chip yourself and then take it to a shop and ask them to fit it, it should be a 5 minute job

[Clunk]

have you tried a new cmos battery?

[schmunk]

have you tried a new cmos battery?

That'd be my first port of call.

[pands@scan]

Exactly what i was going to say

[SteveL]

Well, as it's the general concensus, I'll give it a go. I don't know why that could cause this, 'cause it's only when CMOS is cleared that it will boot, and then it will boot with or without the battery in position.

Cheers

Steve

[djhworld]

It might be a long shot, but....

Are you sure the motherboard isn't setting some dodgey FSB/multiplier values for your CPU?

I had a similar problem once where the FSB was wrong, the only way to boot was to remove the CMOS battery.

[SteveL]

Well, I tried a new CMOS battery, and that made no difference.

Problem now is that it won't boot at all. Always fails to POST, no matter if I leave the battery in or take it out.

Looks like a new motherboard to me

Steve

[pands@scan]

TBH if its not posting anymore, it could just as likely be your RAM or CPU

[latrosicarius]

I had a similar problem, and it wasn't a problem with the battery... some of the capacitors on the mobo itself were leaking and unable to carry a charge.

Sometimes, however, it would also crash while on. You never said yours did that, so it maight be a different problem.

BTW, you don't have to leave the battery out overnight... 5 or 10 minutes will clear the CMOS just fine.

[SteveL]

BTW, you don't have to leave the battery out overnight... 5 or 10 minutes will clear the CMOS just fine.

I found that 2 or 3 hours didn't make any difference, I had to leave the system for ages before it would boot. Maybe the problem isn't CMOS related in that case, it's something else.

Anyway, new Socket A M/B on the way from Scan, so I'll be rebuilding on Tuesday or Wednesday. Finger crossed!

Steve

[AZ_Engineer]

Hi, I'm a new member. I just found this thread and it seems very similar to a situation I'm having with a new ASUS board. If I reset the CMOS, the system asks me to enter the BIOS to setup. If I do, and exit and save, the system won't restart. The video monitor goes black, and the HDD spin but no POST beep. If I enter the BIOS, but escape out and don't save anything, the system boots and runs fine. This happened with the first board so I got the retailer to exchange it for another. Same issue on the second board. Also, both boards randomly had/have problems recognizing all 3 SATA drives. I've tried other cables, etc. I spent a bunch of time with a tech on the phone and he initially thought it was a BIOS code problem. Took about a week, but he found one the boards, and tested it today. He left a voice mail telling me he his board was fine and he suggested an RMA. I'm VERY skeptical that I had two bad boards in a row. But, I was able to convince Fry's to swap the board again, (third board now). Same problem

Also, I've been reading reviews on the web for this board and it seems many are having problems with the board failing to find SATA drives reliably and ASUS always recommends an RMA.

3 boards so far and all the same, clearly it's not the board.
I am running
- P5K-E/WiFi-AP
- Intel Core2Duo 6600
- Two 1GB Kingston memory sticks
- SeaSonic S12-550 PSU
- WD Raptor 150GB
- WD Raptor 74GB
- Seagate 500GB 7200.10
- Liteon DVD/CD burner
- Asus EN6200 graphics card

I tried new batteries on all three boards, and I've tried the latest 0503 BIOS. Tonight the tech emailed suggesting I try another drive to boot.

[Clunk]

Its probably your PSU. There were a number of seasonic S12 PSUs that had problems with Asus boards, exactly as you describe.

Also, test your RAM with memtest test 5, on each stick individually, for about 3 hours each. Do this in all the slots with both sticks.

[AZ_Engineer]

try a new bios chip, it requires a special tool but apart from that its a rip-it-out-plonk-it-in job so it shouldnt cost much

cheapest way is probably to get hold of a new bios chip yourself and then take it to a shop and ask them to fit it, it should be a 5 minute job

I've had the same exact issue with three P5K-E/WiFi boards. Asus tech told me to exchange the first board that had this issue for a 2nd board. Same issue. Asus tech said it's still the board and I got a 3rd board from the retailer. Same problem. It's possible that Asus had a batch of bad chips and all three boards had them, but that seems unlikely...joe

[AZ_Engineer]

have you tried a new cmos battery?

Yes, board #1 no work, new battery no work
board #2 no work, new battery no work
board #3 no work, new battery no work.

I'm thinking it's not the battery. So far I've had 6 different batteries including 3 different brands.

[AZ_Engineer]

Its probably your PSU. There were a number of seasonic S12 PSUs that had problems with Asus boards, exactly as you describe.

Also, test your RAM with memtest test 5, on each stick individually, for about 3 hours each. Do this in all the slots with both sticks.

Mem test passes fine. Can you say more about Seasonic supplies and Asus boards? The original PSU was a Seasonic S12-500. I bought a new Seasonic S12-550 to see if it was the PSU (That was my first thought). The S12-550 has a strange behavior. Often, when restarting the PSU, it will shut down and I have to pull the power cord to reset the PSU. The it boots fine. I have the S12-550 on the way to Seasonic for RMA. I am currently using the Seasonic S12-500.

I have passed many evenings of Memtest with no errors. The Asus tech told me that his system was using the exact same Kingston memory sticks I am using. Also, I have two 1GB modules of Corsair mem and I get the same issue with them...joe