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  Computer wont boot for 24 hours, then starts up no problem. 
 Date Written 
Daniel Robinson Sep 17, 2013, 05:15pm EDT Report Abuse
Its the weirdest thing, if I shutdown my computer, it won't boot up again for at least 24 hours. Nothing happens when the power button is pressed, literally nothing. I'll wait for a day then try again. Sure enough, its boots up with no problem. I have however noticed that the date and time is incorrect when it boots back up. I can put the computer in sleep or even restart it and it will start up again like normal. I'm wondering if the CMOS battery could be causing this issue. Has anyone seen symptoms like this?

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john albrich Sep 17, 2013, 06:00pm EDT Report Abuse
>> Re: Computer wont boot for 24 hours, then starts up no problem.
Stranger things have happened.

If you can't measure your battery voltage using a meter (with all power off including on attached devices, the PSU unplugged from AC, and standard safety and ESD protocols observed), you might try one of the various system monitoring programs available. Your motherboard may even have shipped with a program that monitors hardware and will report the battery's voltage to you.

Since you can boot your system...

If you boot up into BIOS it may also have a battery voltage reporting page/field in a "Hardware" or "Health" or similarly functional section.

Depending on your OS, you may try other freeware/donateware programs such as Speedfan, Open Hardware Monitor, etc. that, if your motherboard provides the sensor, will provide the voltage of the "battery" (aka "coin cell"). They are available at download sites like,, and others.

If you can't do anything to check the voltage, then just buy a new battery and see if it makes a difference. It's a fairly cheap diagnostic. Again, make sure ALL sources of power are off and the AC plug removed from the PSU when you touch inside the computer case. It's not only a safety issue, but otherwise damage may occur to your motherboard. Follow ESD protocols for this operation as well.

On most all current motherboards the battery voltage should be about 3volts, and generally should provide reliable functionality to as low 2.7volts...depends on the motherboard.

Daniel Robinson Sep 17, 2013, 07:53pm EDT Report Abuse
>> Re: Computer wont boot for 24 hours, then starts up no problem.
So I downloaded Open Hardware Monitor. Not sure what value I should be looking at. Im guessing its the 3VCC number, which is currently at 3.328V which makes me think its not the battery. I wish I was more tech savvy. I have no idea what I should be looking at to determine the voltage range for my PSU. This is my current PSU if it helps in any way:

john albrich Sep 17, 2013, 08:08pm EDT Report Abuse
>> Re: Computer wont boot for 24 hours, then starts up no problem.
It shows up with default label of "Vbat" in Open Hardware Monitor.

When installed, Vbat should be an "unhidden" parameter, but to be sure, click on "View" and select "Show Hidden Sensors"

Daniel Robinson Sep 17, 2013, 08:22pm EDT Report Abuse
>> Re: Computer wont boot for 24 hours, then starts up no problem.
Couldn't find VBAT anywhere, but here is a screenshot of what i'm seeing:

john albrich Sep 17, 2013, 11:33pm EDT Report Abuse
>> Re: Computer wont boot for 24 hours, then starts up no problem.
Daniel Robinson said:
Couldn't find VBAT anywhere, but here is a screenshot of what i'm seeing:

What version of Open Hardware Monitor are you using? It's been using Vbat for that parameter since at least ver0.32beta. At least all the versions from either the author's site or (which is now downloading from the author's site...and I've still got all the versions since 0.32beta (which I just installed and verified uses Vbat, and I've been using ver0.6beta).

re: your image (thanks for providing the hidden sensors, too, btw)...
I don't think it's any of the 3 volt readings your image shows, as they are all too high for a 3V lithium coin cell...generally speaking, even a brand new one.

My Open Hardware Monitor doesn't show a "3VSB"

It could be one of the Voltage #5, #6, or #7. Some motherboards don't use standard sensor data locations. It's also possible your motherboard simply doesn't report it at all.

One thing I do see that definitely concerns me, is the varying value your image shows (0.888V to 1.144V) for CPU Vcore. Unless your computer is changing the voltage as part of a power-saving protocol, that large variation should not be there. It should be rock-solid. Set the
to also show the Min column as well to see just how unstable that voltage may be. It currently only shows the "current" and "maximum" values. You need to also look at the "minimum" values.

When not stable, the CPU Vcore voltage varying like (0.888V to 1.144V) can very well be the cause of a computer's random shutdowns. That likely would be a motherboard's on-board power regulator failure as the PSU doesn't supply that voltage. If your motherboard also has a separate CPU power socket (4-pin or 8-pin) make sure it is completely plugged in. If it is, or you are only providing 4-pin power when the CPU needs full 8-pin power (e.g. a high-wattage CPU), or if your motherboard is an older type that doesn't have a CPU power socket, then it could also be a power stability problem with the PSU's +12V rail which I see your image also doesn't seem to show. On older motherboards, CPU voltage regulator may get its power from the PSU's 3.3V rail.

You could also try disabling ALL power management on the computer, both Windows settings and BIOS settings (UEFI settings on newer motherboards), and see if that makes the CPU Vcore voltage become stable. Same thing if you're overclocking or using a software program to "manage" the performance of your computer...something that changes clock frequencies, etc. Those can be problematic.

Another good Windows OS/system info program is HWInfo32. Run it in "Sensors Only" mode. HWInfo32 (or HWInfo64 if 64bit system), also provide a data-logging capability I mentioned in an earlier post. The lithium coin-cell voltage is also defaulted to label VBAT in HWInfo32.

Try it or another system monitoring program and see if you get different results.

edit: to include ref to HWInfo64 and data-logging ability
edit: include info on high-wattage CPU 4-pin v. 8-pin +12V connection
edit: include suggestion to disable ALL power management on computer to evaluate Vcore stability
edit: include info re: overclocking and programs that "manage" computer's clock frequencies, etc.
edit: noted for clarity that VBAT is also default label for battery voltage in HWInfo32/64
edit20130922: WARNING-major HWInfo32 voltage & temp anomolies
I've been using HWInfo32 v4.24.2000 for the past few days on a test computer, and have seen significant glitches in several parameters...particularly "Vcore" and "Temperature 1" (may show as different parms on other motherboards). For example, Vcore was reported to reach a minium of ~0.2V (normally over 1.4V), and Temperature 1 reported a maximum reading of +193 Celcius. These were highly isolated single sample values with nominal values reported just before and immediately after, as opposed to values obtained over several sample intervals...thus almost certainly "glitches". Several similarly low and high value glitches were reported over the period. These were false values. Note: It is possible these glitches originated on the motherboard and HWInfo32 was just reporting what the motherboard data provided, but I haven't seen this with other sensor reporting programs on the same computer. Just be aware of this issue.

(sorry about the multiple edits. I sometimes don't think of every possible scenario at once)



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