Weird startup behaviour of PC

quicky008

Technomancer
I have been facing quite a strange issue with my pc.Sometimes,it only starts up(during cold boot)when i long press the power button on the cabinet.When i do that,the mobo power cycles once then starts loading windows.And as long as its operational,it functions flawlessly with no crashes/freezes etc.

I initially thought the problem might be motherboard related,so i updated the bios but it couldn't resolve the issue.My next suspect was the ram-so i ran memtest but it wasn't able to detect any faults either.

So is the PSU the most likely culprit? This PSU was rma'd once in 2019 as it was randomly causing the pc to turn off.I had a different motherboard back then.

What can i do to resolve this matter?Please advice.

Specs: 10400F,b460 GB mobo,Corsair Txm 550,8+8 gb ddr4 ram.
 

patkim

Cyborg Agent
What if you start PC by shorting the pins on the board? Does it make any difference if the mains switch is off and then you first start mains switch and then press power on button? Are you using any extension box between mains and PSU?
PSU & Mobo work together. There's a circuit on mobo that is running on standby power and co-ordinates with PSU on Pin 16 for on/off etc.
Problem could be anywhere. Try re-seating PSU connectors that plug into mobo.
If you don't have spares, contact Corsair service center asking if they think this could be a PSU issue.
 
Do the PSU short test to find if it has some issue, but might not help much as PC is starting at times:
How to: Test a power supply unit

Another culprit might be the switch in the cabinet itself. Remove its pin from mobo & short the pins manually to start the PC, I used a screwdriver to short the 2 pins on friend's PC when it had some issue. See if your problem still happens.

Also remove CMOS battery from mobo, with PSU turned off hold on power button for 10s, start w/o CMOS, reset BIOS & then later on add back the CMOS battery. For some reason this solved my friend's PC's boot issue.
 

topgear

Super Moderator
Staff member
From Op's post I assume it's not a regular occurrence so instead of power switch try connecting reset switch connectors of cabinet on motherboard power switch header and start your pc using reset button instead for a few days. See where it goes.
 
OP
quicky008

quicky008

Technomancer
Thanks for all the replies. I will be testing whether the pc starts up normally by shorting those pins or not.

Someone recently told me that a bad power cord can prevent the pc from starting properly during cold boots. I have observed that the power cord that was bundled with my corsair psu doesn't seem to work properly unless its fitted quite tightly with the psu's 3 pin connector. If i dont use a bit of force while connecting the power cord to the psu it causes loose connection which prevents the pc from receiving power from the ac outlet.

Can a bad power cord cause these kinds of issues?

@omega44-xt :about 2 months ago i replaced the stock cmos battery of the motherboard with a new Panasonic battery hoping it might solve the problem. While replacing the battery, i checked the voltage of the old battery using my multi meter, and it measured 3.07v whereas the new Panasonic battery gave a reading of 3.21v.

After replacing battery, the issue stopped briefly for some time ie the boot loop during startup didn't occur for 6-7 weeks . But the problem resurfaced again recently so i decided to check the battery again. I took out the Panasonic battery and it read 3.05v on the multimeter-the charge on the battery seems to have dropped quite a bit over the last few weeks. This time i replaced it with a Duracell cr 2032 battery, but quite curiously now the problem still occurs even after installing the new battery!

Is the battery on the mobo getting drained faster than usual?
 

RumbaMon19

Feel Pain.
Thanks for all the replies. I will be testing whether the pc starts up normally by shorting those pins or not.

Someone recently told me that a bad power cord can prevent the pc from starting properly during cold boots. I have observed that the power cord that was bundled with my corsair psu doesn't seem to work properly unless its fitted quite tightly with the psu's 3 pin connector. If i dont use a bit of force while connecting the power cord to the psu it causes loose connection which prevents the pc from receiving power from the ac outlet.

Can a bad power cord cause these kinds of issues?

@omega44-xt :about 2 months ago i replaced the stock cmos battery of the motherboard with a new Panasonic battery hoping it might solve the problem. While replacing the battery, i checked the voltage of the old battery using my multi meter, and it measured 3.07v whereas the new Panasonic battery gave a reading of 3.21v.

After replacing battery, the issue stopped briefly for some time ie the boot loop during startup didn't occur for 6-7 weeks . But the problem resurfaced again recently so i decided to check the battery again. I took out the Panasonic battery and it read 3.05v on the multimeter-the charge on the battery seems to have dropped quite a bit over the last few weeks. This time i replaced it with a Duracell cr 2032 battery, but quite curiously now the problem still occurs even after installing the new battery!

Is the battery on the mobo getting drained faster than usual?

You need to buy a rechargeable coin cell.

The cr2032 you are using is non-rechargeable, and hence depletes faster.

You need to buy ML2032 or VL2032 battery. Which is rechargeable.
 
OP
quicky008

quicky008

Technomancer
I dont think the motherboard has the capability to recharge a CR2032 battery.In all the years that i have been using pc components,i have seen people using only the standard CR2032 batteries for mobos only.Also the stock KTS battery that was present on the mobo appeared to be non-rechargeable one.


Will there be any added advantage in using the rechargeable cr2032 vairants?Can you give the amazon purchase link to one such battery?
 
I dont think the motherboard has the capability to recharge a CR2032 battery.In all the years that i have been using pc components,i have seen people using only the standard CR2032 batteries for mobos only.Also the stock KTS battery that was present on the mobo appeared to be non-rechargeable one.


Will there be any added advantage in using the rechargeable cr2032 vairants?Can you give the amazon purchase link to one such battery?
No idea
 

patkim

Cyborg Agent
To my best understanding motherboards do not have any capacity to recharge CMOS batteries. Such a feature is practically not required given the duration they last. In case any board has such a feature it should be specified in the manual also stating what model of battery to be used on such a board. Otherwise most board manuals specify CR2032. Generally Panasonic are good and come with expiry date written on the cover or casing. Cheap Sony imitations may not be of good quality otherwise.

Generally, CMOS battery comes into picture when you switch off the mains. All other times as long is PSU is good and is plugged into mains, it is in Standby state where is still produces 5V standby for various circuits on mobo including on/off, ethernet etc

If you suspect battery is draining fast it could be indicative of some short somewhere in the RTC or similar circuit that is powered by the battery.

A bad cable or loose connection causes increased resistance and decreased current resulting in part/circuit/device malfunction.

You might have issue like some internal fault in PSU or mobo or external factors like static charges/loose connections/bad cables/bad switches/short/dust on certain parts etc resulting in this kind of start up issues.

Another possibility is that PSU is taking longer than usual to stabilize, so it re-attempts to provide proper power before Power-OK signal is sent to board and hence they together go thru power cycle one more time. Just a guess.

You will have to test one condition at a time for several tries and repeat with another condition till you either isolate the issue or eventually get PSU or mobo serviced and tested.

Intermittent issues like this one could take a while to isolate. If testing for external factors does not help, then replacing PSU/mobo one at a time needs to be done but that could be expensive, unless a local repair shop is willing to test it out for a service fee.
 
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