Possible bad MB or CPU?

[BryanLee]

Problem was solved. Bad power switch.......




Looking for some thoughts from you guys..

I have custom built desktop that fails to either start or remain powered on. The majority (90%) of the time it fails to do anything. If you press the power button the fans will briefly spin then it shuts off. I have a few videos below that will better show what i mean.

Computer Specs

• ASUS M4A77TD PRO Motherboard
• GeForce GTS 250
• 700W ATX Power Supply
• 8GB DDR3 RAM

Here is a video showing what happens when it actually attempts to start
http://s158.photobucket.com/albums/t81/bryanlee1981/?action=view&current=IMG_1175.mp4

This video shows it not starting at all. If i press and hold the power button the fan will spin up briefly 5 times then stop.
http://s158.photobucket.com/albums/t81/bryanlee1981/?action=view&current=IMG_1177.mp4



Things I have tried so far:

• Unplugged everything not required to boot with no change.
• Removed power supply and installed into a known good system. It worked with no issue.
• Checked all cables for good connection
• Removed motherboard and check for bad caps, shorts etc. The light on the board is on.
• Checked CPU and Heat sink for a good connection.
• Replaced RAM with known goods and also tried each slot individually.
• Removed CMOS battery

My thoughts are that it is either a bad CPU or a bad motherboard. I haven't seen this particular issue so I wanted to get some thoughts.

 

[SmithFamilyDesigns]

Just throwing this out there but 2 more things to try that I didn't see:

1) the known good system that you put the psu into, did it have a video card that needed a power connector?

2) when removing unnecessary hardware, did this include swapping the video card?

 

[BryanLee]

The system i swapped with did not have a video card that required a power connector. I did put in a different video card with no change. I even tried with no video card. I got the same result and the MB didn't give a beep code for the missing video card either.

The system is currently on and at the login screen. I'm going to see how long it will stay on.

 

[vdub12]

CPU's rarely go bad. I would say if you question one or the other the 99.9% of the time its going to be the mobo.

make sure you also pull all the header cables from the mobo. USB, audio, and especially the power switch. Turn it on by shorting the power button pins with a screwdriver. Also try a different PSU in this system. It might be a problem with the PSU that is only showing up with that specific configuration and would work fine with another.

Finally you said you checked the heatsink and CPU but did you try and reseat the CPU? When its out check the pins to make sure none are bent.

 

[vdub12]

In addiction is this a brand new system or has it been running fine for a period of time?

 

[BryanLee]

It has been running with no issue. It was left while the owner was traveling and wouldn't start when they got home.

I will try your suggestions.