PC stopped powering up with Asus M4A79T Deluxe Mobo

CaptnCanary

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I've had my PC for 6 years and its been great. Performance is still very good. Today I got home from work and pressed the power button - nothing happened. I tried a few more times - nothing. I pulled it out of the cupboard, unplugged everything and tried a different kettle lead - nothing. I took the side panel off - I can see the power and reset lights lit up. I tried pressing them - nothing. Nothing seems to happen what so ever - no fans, no sounds.
I would really appreciate if somebody can help guide me through some checks to try to figure out what is wrong with it.

This is the Spec:
Case Antec Nine Hundred Two
Motherboard Asus M4A79T Deluxe Motherboard AM3 AMD 790FX ATX RAID SATA Gigabit LAN
CPU AMD Phenom II X4 Quad Core (955) 3.2GHz Processor 4 x 512KB (Boxed) - Black Edition
PSU 750W Thermaltake Toughpower
RAM 4GB (2x2GB) Corsair TwinX XMS3, DDR3 PC3-12800 (1600),240 Pin, Non-ECC Unbuffered, CAS 9-9-9-24,DHX - TW3X4G1600C9DHX
Graphics Card 1 ATI Radeon HD 4870 1GB
Hard Disk 1 Samsung SSD
Hard Disk 2 Western Digital VelociRaptor 150GB (10,000rpm) SATA 16MB 2.5 inch Hard Drive
Hard Disk 3 Western Digital Cavier Green 500GB SATA 32MB Cache Hard Drive
Hard Disk 4 Western Digital Cavier Green 500GB SATA 32MB Cache Hard Drive
DVD Drive 20x DVD±RW DL S-ATA Lightscribe
CPU Cooler Thermaltake Golden Orb II

Mobo manual here: http://www.orbitmicro.com/download/resources/M4A79T_Manual.pdf

Thanks
Steve
 
Solution

Cazauxx

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I'm afraid your motherboard might have died :( :( :( :(
I hate it when these things happen
Just to double check when you start the computer do the fans spin at max capacity and does no display show onscreen?
Since this motherboard is 6 years old it has reached its lifespan. (Motherboards usually only last 4 years)
Just purchase a new motherboard or take it to a technician

ALTHOUGH!!
Since you said there is no life coming from the pc at all the power supply must be the issue
If there is no light at the back of the power supply that means it has definetely died
Just replace it with the same/new one

Hope This helps :)
 

CaptnCanary

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Absolutely nothing happens when I try to power on. No fans at all. The only sign of life is the standby and reset lights on the motherboard glowing. Those flicker quite a bit - not sure if that's normal?
Is there definitely a light on the Thermaltake PSU? I've not noticed one. I am looking at possible replacement PSU's. Can you recommend one at a reasonable price for purchase in UK?
Thanks
 

Cazauxx

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That means the PSU is faulty. Since the motherboard light is flickering that means the PSU isnt supplying enough power to motherboard to start the pc.
Just replace the psu but before doing so try this. It helped someone else
UN-plug the power supply from the wall........... (or turn off with the switch on the back of the supply)

Then WAIT until the GREEN LED on the motherboard goes Off.....

STEP #1 : Now...

- remove ALL the RAM sticks
- remove all SATA cable completely from the system (yup pull 'em out and set them across the room...)
- unplug all the hard drives, DVD drives, and floppy(hey ya might have one... :) ) from the power supply
- unplug all fans from the motherboard
- unplug the 4+4-Pin ATX 12V from the CPU, yes, unplug it too
- unplug all the front panel switches
- unplug all front panel USB cables
- unplug the front panel audio cable
- unplug your mouse, keyboard, or any thing else you have connected to a USB port

There should be no wires, cables, or devices of ANY kind connected to the motherboard...............


The ONLY cable from the power supply that should be connected to ANYTHING is;
- the 24 pin cable to the motherboard



Turn the supply back on....

If the GREEN LED on the motherboard still blinks:
- its the CPU
- or the motherboard
- or the power supply (SO, try Both of the power supplies you have now...)


STEP #2 (If the GREEN LED on the motherboard still blinks)

Next step would be remove the power supply and motherboard from the case. Set them on a non-conductive surface, like card board. Connect just the 24 pin cable again. See if the LED blinks when the supply is turned on. (some times the metal stand off's or the screws holding down the motherboard to those stand off's cause a short circuit. Sitting out side the case on card board we've eliminated that possibility)


STEP #3 (If the GREEN LED on the motherboard still blinks)

Remove the CPU from the motherboard....

Turn on the power


STEP # 4 (If the GREEN LED on the motherboard still blinks)

The motherboard is bad....
Or, you just have two (2) bad power supplies....


The GREEN LED is powered by the 5 VSB power. That LED should not blink if the voltage remains on and steady. Were trying to find out if something is pulling that voltage down (or shorting it out...)


Hope this helps :)
 
Solution

CaptnCanary

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Jul 9, 2015
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When I said the power/reset lights flicker I probably should have been a bit more clear - its just a slight flicker and the lights never actually go out. Its at a level where I would say its possibly normal behaviour.
I am hoping that the PSU is indeed at fault as I'm not confident about swapping out the motherboard. I have removed the PSU from the PC case. I tried it with just the 2 power cables to the Mobo plugged in. Still nothing happened.
Is there some way I can test the PSU to confirm it is at fault? Maybe shorting a couple of pins should cause the fan to operate or something? I don't have a multimeter but I would with some electronics guys who might be able to take a look at it tomorrow. I just want to confirm the PSU is at fault before ordering a new one. I've picked out the EVGA Supernova G2 750W as a good quality replacement but its going to cost me around £80 ($120). Even a cheaper Corsair one is £70 in the UK.
Thanks
 

Cazauxx

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If the light flickers that means the power is a bit dodgy. Purchase a new power supply to fix this issue as it might be a bit old

Hope this helps
 

CaptnCanary

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Today I took the PSU in to work with me where there are some electrical guys. I connected the green wire with a black wire on the 24pin connector - The fan spins up as it says it should in the PSU manual. I then measured the voltage on every pin on the 24pin connector and all read correct voltages, again as per the manual. This evening a colleague is taking the PSU home to try it out on their PC. Its kinda looking like the PSU is OK though. If it works fine on my colleagues machine, how do I go about diagnosing the Motherboard?
Thanks

EDIT: PSU didn't work on mates machine so I've ordered a new one.