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Bad Mobo or PSU? PC not posting after sudden shutdown. No Beeps during power on cycle.

Last response: in Systems
May 11, 2013 10:40:32 PM


This afternoon I was playing a game (DOTA 2) and my PC suddenly turned off. It turned off suddenly and without any warning (such as a blue-screen). My computer was unable to post when I attempted to restart the system. I've posted two videos of what happens when I attempt to restart. I think the cause of this is likely a bad motherboard or PSU.

My system specs:
1. ASUS P67 Motherboard
2. Intel i6 2600k processor
3. ASUS Nvidia Geforce GTX 590. (This gpu has a feature where its logo will successfully light up if the card detects sufficient power and blink if there is insufficient power)
4. Corsair TX 650W power supply
5. Corsair H60 Pump Cooler
6. 4 sticks of corsair memory. (8gb total)
7. 1 Solid state hard drive
8. 2 additional non solid state hard drives
9. 1 DVD drive.
10. 50mm assist fan hooked directly

Trying to restart my system consistently leads to the two things.

In both these cases.
⦁ The system cannot post.
⦁ There have been no post beeps or any sounds from the from the internal motherboard speaker.
⦁ GTX 590 GPU does not light up at all.
⦁ The motherboard's standby light is green when the PSU is flipped on.
⦁ The power button (on the front panel of the PC) is unresponsive. I am forced to use the PSU's switch to shut down the PC.

First case: The PC will temporarily power on. My board's red LEDS will flash and then nothing happens. The case fans do not light up or spin.

Second case:)  The PC will power on. The board's red LEDS will turn on and persist. My case fans light up and spin properly. I can feel the GPU fan working underneath but I do not feel the H60's fan. The 50mm assist fan will spin (it is not plugged in the video).

(Sorry these videos were shot with my smartphone)

I've had a prior experience with abrupt shutdowns.
A few months ago, this same exact sudden shutdown occurred.
Cleaning, re-seating, re-plugging everything had no effect.
Eventually resetting the CMOS jumper easily fixed the issue for me.
Ever since then, my computer posted and I've had no problems until today.

Some troubleshooting steps I've taken:
The first thing I did was reset my CMOS jumper.
Re-plug all the PSU pins.
Reseat Memory, GPU
Power on with only 1 ram slot.
Unplug non essential items and try to restart.
(Some other basic stuff but it's slipped my mind).
I looked through the troubleshooting checklist and tried many of the steps.
Looked through other threads and try the suggested answers
Finally - When I was taking troubleshooting steps earlier (with only 1 ram slot, keyboard, gpu - no display connector, cpu, hard drives), my PC sucessfully posted (the GPU even lit up). At that point I assumed a cord had gotten loose was the cause of all my problems.
I used the front power button to shut down my pc and proceeded to replug everything. The system would not post when I attempted to repower it. I have tried various other steps (and attempted to power the system with only one ram slot multiple times) but I haven't been able to post my system since then.

Since I was able to successfully post and complete a power cycle, I feel that the culprit is likely my motherboard or PSU as opposed to a faulty component.

I have not had any chronic problems with overheating, system stability and etc.

I'll see if I can borrow any spare PSUs from friends so I can test further.
I might consider buying a PSU tester. Are there any good PSU tester recommendations (particularly ones that can indicate whether or not a PSU is carrying its full load)

I'm wondering if anybody can shed some light or advice.

May 13, 2013 1:38:53 AM

Turns out it was the power supply. The PSU was still partially functioning but unable to provide it's full current.
I was fortunate enough to borrow a spare PSU (same exact make and model) from my friend, replaced the PSU and my system works perfectly now.
I'll also be investing in another power supply.