CPU Fan starts and shuts off

My HP desktop will not power up. After pressing power on button, power on light stays on , CPU fan and case fan start for a few seconds then stop , no beeps from mother board, power supply unit seems to be working fine it has 5 , 3.3 and 12 volts.

 

The model number of the HP system would be helpful, we can see what problems a specific model had during it's run.

I just worked on an HP A1610n system doing a similar thing- system had power, all fans stayed on but no display, no beeps. Turned out the motherboard was shot and from what I could find on the net, that is a very common problem with that model lines motherboard (an Asus A8M2N-LA). As the CPU and memory were OK, I just ended up picking up an inexpensive ($30) motherboard that supported that CPU (Athlon 64 x2) and memory type (DDR2) and all is good.

Sam

 

My model HP P6115y

 

If you feel comfortable doing this, open up the case and take a look at the motherboard inside. You are looking for any leaking or popped capacitors. The photo below shows what a good and bad capacitor looks like:

http://www.thenakedpc.com/dan/Bulging_Capacitors/close-up.jpg

 

If it looks like what collinsl posted an easy way to fix a leaking cap is to remove the corrosion and put a drop of hot glue on the top of it. Works like a charm. I had to do that to the machine I'm running right now.

 

All capacitors look good.

 

Could be the power supply, if you have access to another one you could try it. The usual troubleshooting stuff too- remove memory, disconnect hard drive, CD/DVD drive, front panel USB/memory card reader (have been issues in the past with those on HP systems) and see if you get power to stay on, beeps, etc. If you get beeps w/o memory put it back in 1 stick at a time, hook up hard drive, DVD, etc. Power off the system before you remove/add anything each time.

Those boards do seem to have a tendency to die from what I could find on the net about them (model M2N78-LA, made by Pegatron which has something to do with Asus who makes a ton of boards for HP/Compaq systems).

I just had to replace the power supply in my Dad's system- it would get to the Windows splash screen and just shut down. replaced the power supply and it runs fine now.

Sam