Motherboard or PSU - PC boot unsuccessful, which is the culprit?

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Kflyn30

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Hey guys,

I'm currently having an issue with my PC's bootup that has progressively worsened. The boot failures first occurred a few months ago but, due to work and school, I didn't attempt to repair until yesterday. With everything connected, the components would momentarily come on - fans, HDD, and dvd drives - and then get stuck in a boot loop. As a result, distinguishing the PSU as the issue. I did the paperclip test on the psu and it worked fine. Upon plugging into the motherboard again, the PC booted by shorting the power pins without issue and sat on the windows login screen without issue. I then turned it off with the onscreen shutdown and left it, assuming it was fixed. It was left on standby.

The night after (today), I attempted to bootup but none of the components (leds, gpu or fans) powered up. Motherboard and gpu led's showed power was coming from psu. Another paperclip test showed the psu was working and powering up the non-motherboard related devices. Disconnection of everything bar ram, cpu, and heatsink and no power would boot up. Potentially a broken 24-pin connector following paperclip?

So if you wonderful people could assist in me getting down to the gritty and working out which component is at fault, that would be great. I have looked at other threads on this but none can explain the normal bootup experienced last night.

Thanks
 
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R_1
sorry bit of vernacular confusion, this is a PCIe to Sata power cable and it used the SATA power cables to power the video card, not the other way around. wrong adapter.
http://g02.a.alicdn.com/kf/HTB18YgfHVXXXXaJXXXXq6xXFXXXS/Free-shipping-15Pin-SATA-male-To-6Pin-Female-PCI-E-Graphics-Video-Card-Power-Cable-support.jpg
did you mean a molex to sata power adapter? one of these?
http://www.datoptic.com/ec/media/catalog/product/cache/1/image/1200x1200/9df78eab33525d08d6e5fb8d27136e95/p/c/pcable-sata-2_1.jpg

I have run a system with 2 separate PSU before. be sure to power the hard drives/cd drives before the system. will ensure the BIOS detects them.
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R_1

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the paperclip test is mostly useless, all it checks is that the power supply can actually turn on. it does not mean the PSU can provide the current under load, the power supply is still in question.
unless you were very very violent with the 24pin plug I think its fine.
"With everything connected" is the speaker connected to the 4pin plug on the motherboard marked speaker/spkr?
if the speaker is installed you should be getting diagnostic beeps/beep codes. what are they telling you?
if the speaker is connected, with the PC off remove all the RAM from the slots and try to boot the system. the motherboard should beep at you. as example my no RAM beep code is 4 short beeps, pause and repeat.
 
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Kflyn30

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Thank you for the reply.

My apologies but I forgot to mention that my motherboard lacks a speaker for some reason. So whenever it boots, successfully or not, it does so without a beep. Anyhow, removing the RAM has not resulted in a boot.

All the symptoms of the initial issue - prior to the successful boot - pointed towards a power related issue; as per the GIGABYTE Guide: http://www.tomshardware.com/forum/275856-30-gigabyte-guide. But it suggests that the PSU was capable of having enough power to get the motherboard kicking off. Furthermore, the success afterwards suggests the PSU wiggled itself into a normal state - maybe the 24hr standby did something dodgy to it?

The thing that's puzzling me is the intermittence; going from full, stable boot to absolute nought system activity.


 
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can you be creative? if you have a speaker, any speaker, you can hook it up for diagnostic purposes. like the guide says it can be invaluable.
I have used scraps of wire and a bookshelf speaker as a temp solution.
the pins are 1 and 4 on the motherboard. the insulation should stretch so you can just push the stranded (must be stranded wire) wire into the pin it will be fine for temp testing connect the other end to speaker. boot and count.
they sell speaker buzzer units that plug in to the motherboard. they make diagnosing issue much easier.

do you have or can you borrow for testing a spare PSU. siblings/parents/friends computer maybe?
 
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Kflyn30

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Apologies for the late reply, I haven't been home all holiday season. I have managed to get a friend's old pus into my system and it has confirmed my feelings that it was PSU related - successful boot. However, I am unable to power my HDD and optical drive with the PCIe to SATA power cables. If I run a dual PSU system, where the old PSU only powers the HDD, I can run the computer as normal. Obviously, this is far from ideal. Is there anything to explain the lack of power to the HDD on the new pus?
 
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sorry bit of vernacular confusion, this is a PCIe to Sata power cable and it used the SATA power cables to power the video card, not the other way around. wrong adapter.
http://g02.a.alicdn.com/kf/HTB18YgfHVXXXXaJXXXXq6xXFXXXS/Free-shipping-15Pin-SATA-male-To-6Pin-Female-PCI-E-Graphics-Video-Card-Power-Cable-support.jpg
did you mean a molex to sata power adapter? one of these?
http://www.datoptic.com/ec/media/catalog/product/cache/1/image/1200x1200/9df78eab33525d08d6e5fb8d27136e95/p/c/pcable-sata-2_1.jpg

I have run a system with 2 separate PSU before. be sure to power the hard drives/cd drives before the system. will ensure the BIOS detects them.
 
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