Hi guys. So I unplugged my PC for about a week (outstation). When I come back home, it won't turn on, the power led was on and fans were spinning for half a sec then it just shuts off.

I opened the case. Basically reconnecting everything, and it started again normally. I thought it was just the mobo power cable connection. I even game on it for a bit this morning. Suddenly, just after finished gaming (game closed already), the pc shuts off by itself, and tries to start back up and fails again in a loop.

Any ideas?

Do you have a spare PSU to test it on your pc?

Not currently. Planning to borrow a friend's but his is only a 250w. Is it enough for a i5-3470 and a 7870?

For just i5, is enough, with 7870, no. So, u may need to test your PC with onboard display if using your friend's 250w.
If u just want to get it bootup and load into windows, u can get yourself a pair of molex 4 pin to 6 pin converter, beware that if u do this, this is just enuf for idling, if u go and start a game, that could fried your friend's 250w instantly.

Yeah, I just want to isolate the issue to the psu.

Hi sifus. An update here. I tested my pc with a friend's psu. An aerocool 550w 80+ bronze and it still does not work. Does this mean the problem is not psu? Any ideas on the next step?

- swap graphic card or try using onboard if available
- reset CMOS

When u say unplugged when u left your PC for outstation, what else cable still being plugged ? Like LAN cable, VGA/DVI cable or 3.5mm audio jack ?

Reset cmos even if I did have never messed with the bios?
Everything else was plugged. I only meant the power to the psu was off.

This post has been edited by Ronin_Amin: Nov 30 2015, 06:52 PM

Restart loop?
Could be HDD problem either Windows is corrupted or motherboard can't detect the HDD.

You can download the HDD diagnosis program from the HDD maker site.

This post has been edited by WebWalker: Nov 30 2015, 06:56 PM

A lot of things could happen, no harm giving a try, it will just reset all the setting back to default.

Well... Is rainy season, that means thunderstorm, while u were not at home, your PC could have been surge damage, power off doesn't necessary means surging won't found its way into your PC.

Yeah the surge damage is one of my concerns. But wont the psu be fried first?

It can damage both your psu and mobo as well. U using LAN as internet connection ?

Yup. Lan as internet connection. So just to confirm, since I used my friend's PSU and it still doesn't start, my PSU is fine right?

High chances are still fine, u can do a simple test by shorting green color to any black color wire to confirm. By shorting it, it will turn on the PSU, if fan are running most of the time it is fine.
http://aphnetworks.com/tutorials/psu_paperclip_trick

Yeah the psu fan is still running. I just used the normal method to turn it on.

This post has been edited by Ronin_Amin: Dec 1 2015, 02:13 PM

Is it considered a restart loop it it just turns on the fan for a sec and then the power led lights up and everything turns back off and the whole thing starts again? Monitor does not even turn on.

check your system to see if there are any dead lizard or cockroach inside. Maybe it is causing the problem.

I have already reopened the system and reconnected all the cables. Nothing unusual was found.

suspect dead cmos battery
replace a new battery, it just few ringgit only
buy for backup oso can

cmos died due to lightning? Where to buy cmos? All mobo same cmos?

If the computer shut down itself and not due to PSU problem, and unable to start even replacing the PSU, high possibilities it is the mobo problem.

CMOS battery dead won't cause the computer to shut down itself or cause the computer cannot boot.
Just all setting back in the CMOS to default status and time back to default starting time.

most intel board already have VGA port...250w is enough to run without the graphic card...
good luck

So how properly confirm it is the motherboard?

Since I think the PSU is ok (because used friend PSU on pc and still same problem), should I also test my PSU to power up a friends pc? If the PSU is faulty, would this cause problem to their pc?

Also since people suggest it might be a corrupted hard disk, I was thinking of putting my ssd in a friends pc and see if it can boot.

I guess the first step is to try if it can boot with only the ssd, cpu, mobo and ram?

Would secondary hard drives being corrupted cause this problem?

Sorry for so many unstructured questions, really worried about this.

corrupted hdd will only make your computer restart...won't turn off the led and stuffs
you can try disconnecting ssd and hdd and boot it up...

since using your friend's psu still facing the same issue, your psu should be fine....

suspect might be mobo issue

Corrupted HDD only cause you won't able to boot up into Window or OS, the motherboard still display boot sequence aka detecting HDD, etc.

The main culprit of scenario of "push the button and nothing come out", most likely possibility are always either PSU and Mobo.

HDD died - screen still show boot sequence and detecting HDD, just it will tell you the system fail to detect any HDD
RAM - no display, but won't shut off itself one (if not mistaken), bluescreen during usage, freezing etc.

check your cmos battery, usually wont died wan but no harm replacing it, all mobo use same wan.

boot loop could also be caused by improperly seated RAM or bad RAM sticks. Try reseating your RAM sticks or use 1pc only, if cant try clean the gold contacts with a lint free cloth + isopropyl alchohol (or gently rub with eraser).

also try to breadboard, eg. remove extra components and test with just CPU+cooler, 1 RAM stick + boot disk.

Owh, I got a 550w PSU from a friend. So that's ok.

Well there is the fans spinning for a bit and power led on but both stop and restart again. I guess that means it's probably not the ssd? I will also try using the ssd in a friends PC this weekend to make sure the ssd is not the cause.


Any idea where to buy cmos battery? Yeah I am planning to test the ram and the ram slots. Only have 1 stick though.

Any testing would have to wait till this weekend as I am once again away from home. I unplugged everything from wall this time though.
I really was planning to keep the CPU, mobo, and ram for a few generations as the CPU improvements are great for gaming. Does gigabyte motherboard have 3 year warranty? Otherwise might have to look for a mobo for i5-3470.

Thanks for the help so far. Will keep this updated.

according to what u posted, it couldnt b a lightning struck issue
lightning strike will cause psu or mobo dead directly, u wont able to power on
http://www.lelong.com.my/kx/battery+cr2032.htm
walk in to nearest computer shop to get 1 or get from online store for a pack

Yeah, I only know that a lightning struck my house causing a blackout. Not entirely sure if it surged my pc or not (hopefully not). I guess the mobo (possibly) just died randomly?

didnt you say you unplugged the Pc for a week when outstation?? your LAN cable got unplug?

Sorry by that I mean switch off. Everything was still plugged to the wall and even lan cable was plugged.

To confirm the motherboard, u need to get it tested, like try other RAM / processor, that the basic way.
Most of the time, secondary HDD won't cause any prob, unless your PC is configured to boot by using UEFI method instead of Legacy boot mode. I have seen PC, just because HDD OS corrupted causing no display, no POST symptoms, reset the CMOS everything is back to normal. However this still doesn't relate to your self off symptoms, so this is just for your FYI only.

This depends on how sensitive is your house's ELCB. There are a lot of people with ELCB set to a highly less sensitive level causing all kinds of household appliances damages. But if the surge comes from telephone line, then most of the time the network IC is fried (but hey... still the surge can go elsewhere in your PC until it finds its way to ground, and that means multiple component damage). When it fried, sometime it can be presented as a shorted circuit, and the mobo detects that shorts, it immediately off it self as a safety measure. Most of the time, when network IC was fried, the IC itself become extremely hot when it was turned on.

Update:
After I come back to my house and plugged all the power cables, suddenly my pc turns on.
Things I changed
1. I didn't cable manage, just plug it all the power cables so I can just test the pc for a while.
2. I didn't use an extension cable for the power cable to the 4 pin cpu socket. I used this before to get a neater cable managment.

I am somewhat sceptical that the problem is solved since the last time it turned on, after about 12 hours the problem start again.

So sifus any idea? Do you think it was the cpu extension cable?

I kinda suspect is the ATX 24 pin power connector. Try press down the ATX 24 pin power connector firmly while powering on, i have seen loose ATX power cable causing similar symptoms. Do so for the CPU 4 pin as well to confirm.

I have been running memtest all night, I think 9 passes currently. I am thinking of doing a cpu stress test, gpu stress test, and psu stress test afterwards. Just to eliminate other possibilities.

So does this mean my mobo is fine?

Can consider no prob

Alright. That's good. So if it was the loose psu connectors can I just tape or should I send back for RMA?

Inspect the ATX 24 pin on the mobo for corrosion 1st, corrosion can reduce ability to conduct electricity.
How loose is the connector ? with a light pull come off or still lock in place but can wiggle freely ?
Can RMA or not i didn't experience sending in board with ATX loose prob for RMA, so that one left it for expert to answer

So I think I have the cause. It was the 4-pin cable extension. It seem to have burned at the end. Everything is running fine now but should I be worried about what was causing the burn in the first place?

4-pin cable

I also don't know how to post picture on these forums lol

This post has been edited by Ronin_Amin: Dec 6 2015, 07:54 PM

2 way a cable can burn like that :
- short circuit (that could be short either with the cable itself or on the VRM circuit of your mobo, but now your PC can work normally, short on VRM can be rule out)
- Over current, a cable is rated "safe" at a certain amount of current (Amp), if over the rated value, then it will heat up until it burn and melt. Do u overclock your PC ?

Anyway, why u decided to use an 4 pin extension on the 1st place ?

The 4-pin cable from the psu couldn't reach the cpu pin on the mobo if I were to wired it behind the case. Essentially, it was for better looking cable management. I only overclock my GPU and I didn't even mess with the voltage of that.

Im currently facing the same prob this morning

From my experience, check all the cables first. Check for signs of defects (burning, etc).