• Guest, The rules for the P & N subforum have been updated to prohibit "ad hominem" or personal attacks against other posters. See the full details in the post "Politics and News Rules & Guidelines."

Question Gigabyte Motherboard Will Not POST On Cold Boot Unless CMOS is Cleared

reallyscrued

Platinum Member
Jul 28, 2004
2,613
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.
 

VirtualLarry

No Lifer
Aug 25, 2001
51,362
6,592
126
Q: Have you tried REPLACING the CMOS battery, with a fresh one, and then clearing CMOS, and then booting (Hit F1 / DEL to go to BIOS, set date/time, 'Save and Exit').
 

reallyscrued

Platinum Member
Jul 28, 2004
2,613
5
81
Q: Have you tried REPLACING the CMOS battery, with a fresh one, and then clearing CMOS, and then booting (Hit F1 / DEL to go to BIOS, set date/time, 'Save and Exit').
Thanks for the prompt reply, I think maybe I didn't explain the situation correctly, the current battery is indeed holding the last configuration. But the board refuses to POST (or seems as such) when there is a previous configuration present.

But no harm in trying what you suggested - I don't have a brand new CMOS battery but I removed one from my Optiplex 980 I have. The Optiplex shows a warning when the battery is low so I'm sure this battery has juice, and its BIOS config does indeed save if the power is gone for a significant period of time.

I'll give it a try with this battery but right now the board is in a state of refusing to POST. When I can get it back on (again, can't figure out a way to get it back other than to leave the PSU switched to 0 and battery-less), I'll start it up with the Optiplex's battery, go into the BIOS, and save the time and date.

What I'm expecting will happen then is that the board will soft reboot, with time and date saved, but when I go to cut the power off, and start it up again from a cold boot, it will refuse to boot until I clear the CMOS again.

Will report back.

EDIT: I realize now that the title to my topic might be unclear - to clarify: it's not that every time the board loses power, I'm greeted with a message that says 'CMOS Settings Lost'! That's obviously a failing battery.

What I'm experiencing is that the board literally, refuses to POST, if you happen to hard reboot it, *until* the CMOS is cleared.
 

VirtualLarry

No Lifer
Aug 25, 2001
51,362
6,592
126
Hmm, I wonder if your current PSU's +5Vsb (StandBy) voltage rail might be low/failing. That interacts with the CMOS, and booting the motherboard.

After you try swapping in a known-good CMOS battery, and clearing the CMOS properly with the jumper, try that, if that doesn't work, try swapping in a PSU?

That happened to a friend of mine, his +5Vsb line had failed in his maybe 3-4 year old PSU (it was kind of a budget one, he had a mid-range Athlon II rig, nothing too fancy or expensive to warrant a top-of-the-line Seasonic Gold PSU, that would have cost nearly as much as his whole system was worth). Anyways, pressing the power button... like nothing would happen... for like ... a minute or two... then... it ... would... finally... boot.
 

reallyscrued

Platinum Member
Jul 28, 2004
2,613
5
81
Yeah, that's what I thought too. I'm using a brand new PSU - this one:


Same symptoms with this PSU, and I can use this PSU on another, more high wattage computer (Fx-6300 with a 1650 Super) and it POSTS, reboots, stress tests just fine.

Definitely not the PSU.

Is it possible that could be failing from the mobo side? I have a voltmeter if there are some easy ways to test that.

Just tried with a different CPU fan in case maybe it thought the CPU fan was failing upon cold boots? A 3 pin, no difference.
 

VirtualLarry

No Lifer
Aug 25, 2001
51,362
6,592
126
I'm sorry to say, that if a fresh CMOS battery, and a fresh PSU didn't solve it, then it certainly points strongly to the mobo being at fault.

Have you unplugged all of your +5V peripherals (USB)? Some mobos also power the USB ports through the +5Vsb line, to allow them to power-on / wake the PC, or charge a phone while the PC is in a soft-off state. This can be too much for some PSU's +5Vsb line, they generally don't have much current capacity (on the order of 2.5-3.0A @ 5V). I generally-speaking, MUCH prefer to set a jumper (older mobos used physical jumpers for this), or CMOS/UEFI settings (disable "allow charge on USB power when power-off", or anything similar-sounding), to set the USB ports to use the +5V line, which is only active when the PC is actively in a power-on state. This of course means that you cannot charge your cell phone or MP3 player or power your USB desktop fan when the PC is "turned off", but ... there's little loss there, IMHO.
 

VirtualLarry

No Lifer
Aug 25, 2001
51,362
6,592
126
Lastly, do you use anything DisplayPort or USB-C on this PC? There are some complications with some DisplayPort cables passing +5V when they shouldn't, and this can cause a strain on the PC's PSU and/or circuits in the area, and can cause crashes and weirdness.

If you are using a DisplayPort display, make sure to use a "VESA-compliant" DP cable, such as Accell sells on Amazon.
 

reallyscrued

Platinum Member
Jul 28, 2004
2,613
5
81
Only USB device connected on reboot would be keyboard, I'll try with a PS/2 keyboard and see if that uncovers something.

Nope, no display port, using the on-board HDMI out. Also tried with a Radeon 7450 DVI out, and same symptoms, will not POST on soft reboot until CMOS is cleared.

I'm beginning to wonder if there's something special that's happening, like some sort of initialization process, during the cleared CMOS procedure that the mobo goes through that's important for it to cold boot, and it's not happening on soft reboots?

Also, is it unusual that clearing the CMOS takes so long? Even jumping the pins, it takes 30 minutes no matter what to clear the CMOS. You could leave the battery out, remove the AC power from the wall, it still refuses to boot until many tens of minutes have passed.

This Gigabyte board has Dual BIOS on it, does that have something to do with it maybe? It's annoying that it's a perfectly fine mobo once it's up and running.
 

VirtualLarry

No Lifer
Aug 25, 2001
51,362
6,592
126
This Gigabyte board has Dual BIOS on it, does that have something to do with it maybe?
It might. It might be copying/flashing the backup BIOS over the main BIOS every time you boot, after clearing CMOS.

Normally, after clearing CMOS, the board goes through some additional identification routines, I believe, for the CPU and RAM sub-timings.

Maybe the main BIOS chip/partition is actually defective or bad in some area, and it overwrites it every time you clear-CMOS-boot, somehow?

Weird behavior all around.

Have you tried flash the BIOS to a newer or even older version?

What platform is this again?
 

VirtualLarry

No Lifer
Aug 25, 2001
51,362
6,592
126
If nothing else, I've got a 970-chipset AM3+ mobo sitting here on the floor behind me. PM me if interested and we can discuss. AFAIK, there's no chipset iGPU on the 970, though, so you would need a video card. I've got a GT 740 GDDR5 card too.
 
Last edited:

DAPUNISHER

Super Moderator and Elite Member
Moderator
Aug 22, 2001
22,842
4,294
136
It might. It might be copying/flashing the backup BIOS over the main BIOS every time you boot, after clearing CMOS.

Normally, after clearing CMOS, the board goes through some additional identification routines, I believe, for the CPU and RAM sub-timings.

Maybe the main BIOS chip/partition is actually defective or bad in some area, and it overwrites it every time you clear-CMOS-boot, somehow?

Weird behavior all around.

Have you tried flash the BIOS to a newer or even older version?

What platform is this again?
I have seen this before, and a bad bios was indeed the reason for it. Download and run Gigabyte' dual bios rescue utility, it should fix the issue.
 
  • Like
Reactions: VirtualLarry

reallyscrued

Platinum Member
Jul 28, 2004
2,613
5
81
I have seen this before, and a bad bios was indeed the reason for it. Download and run Gigabyte' dual bios rescue utility, it should fix the issue.
Could you point me to the Dual BIOS rescue utility? All my google search turned up was :


Not very helpful.

BIOS wise - I'm having a lot of trouble flashing the BIOS on the board.

Gigabyte's @Bios Windows utility refuses to install on XP-32 and Win7-32, so I used the embedded QFlash Utility and a FAT32 hard drive with a BIOS file to flash it.

It still exhibits the same problem, even though the flash went through normally.

I'm going to try and downgrade the BIOS to vF1 until I come across that Dual BIOS rescue utility.
 

reallyscrued

Platinum Member
Jul 28, 2004
2,613
5
81
Okay, learned something new, but made no progress.

Here is what I managed to do, using these instructions:


1. I used Q-flash to flash the main BIOS back to vF1
2. Soft reboot and confirmed vF1 was indeed the BIOS version during POST screen
3. Used Alt + F12 to enter utility to flash main BIOS into backup BIOS
4. Backup BIOS flashed successfuly, received instruction to reset computer
5. Soft reboot worked fine.
6. Moment of truth, hard reboot. Turned system off entirely. Tried to turn it back on...and no POST. CPU fan spinning. No beeps, no monitor signal, no keyboard lights or activity lights.


Try this utility -

http://redirect.viglink.com/?key=71fe2139a887ad501313cd8cce3053c5&subId=6560288&u=https://download.gigabyte.com/FileList/Utility/mb_utility_gfu_B19.0227.1.zip

And run DualBiosRescue.exe

If it is not compatible with your board, e-mail Gigabyte and ask for the one that is.
Thanks, will try this next.
 
  • Like
Reactions: DAPUNISHER

reallyscrued

Platinum Member
Jul 28, 2004
2,613
5
81
@DAPUNISHER - Update:

It seems that DualBiosRescue.exe should fix the problem I'm experiencing as per this thread:


However I cannot get the program to start up no matter what I try.

I tried on Win7-32 and Win10-64. Both operating systems have the same issue, I receive the elevated privilege prompt, click 'Continue', then the program flashes in the task manager for a second and shuts down.

I'd like to contact Gigabyte at this point as you suggested but it seems like their link to their technical support is actually linked to their _non_ technical support...not sure how that happened.


I'm going to try email support@gigabyte.com and see if that routes to anywhere helpful.
 
  • Like
Reactions: DAPUNISHER

DAPUNISHER

Super Moderator and Elite Member
Moderator
Aug 22, 2001
22,842
4,294
136
That is the thread I bookmarked a ways back, when I was having trouble with a Gigabyte B450. I was worried it would not be compatible with yours'. That email should eventually get you to who you need to talk to. Good luck and let us know how it goes.
 

reallyscrued

Platinum Member
Jul 28, 2004
2,613
5
81
Update: Gigabyte eSupport reported back that there is no "firmware update utility" compatible with this board, and thus no DualBiosRescue.exe available for it.

What a dumb ending for an otherwise useable board :(
 

ASK THE COMMUNITY