I built a system last week and it worked perfectly for about 5 days. Then I noticed a high pitched whine. Following the sound to my system, I noticed it was quite warm. I shut it down, opened it up and notice that just about everything connected to the motherboard was very hot (PCU, GPU, and memory). After cooling down, I tried to restart the system. All fans turned on and the hard drive spun up, but the motherboard would not post. There was no output to the monitor and there were no beeps from the speaker.
A family member noticed the whining sound had been occurring for about 2-3 hours before I noticed it and shut the system down.
The following components were used:
AMD Athlon II X4 620
GIGABYTE GA-MA785G-UD3H AM3
APEVIA X-MASTER Case with 500W PSU
G.SKILL 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 1066
Things I tried without any change in results:
1. Removing GPU and connecting monitor to IGP (tried both DVI and VGA)
2. Disconnected hard drive and optical drive
3. Testing PSU voltages (tested OK)
4. Replacing PSU with known good.
5. Removing one Memory stick
6. Replacing memory with known good (different brand OCZ).
7. Replacing motherboard (with all memory stick combinations)
Again, the PSU powers up and all fans spin (PSU, CPU, Case), but there are no beeps and nothing on the monitor. I then removed all memory sticks and powered up again. Doing this gives me 4 long beeps, a long pause and then repeats (so I know the speaker is working).
At this point, I have nothing else to suspect accept the CPU itself. Before I RMA the CPU, I wanted to know if was missing anything… any diagnostic test or change that I can test before assuming it is the CPU.
Well, I already replaced the motherboard and that didn't change anything.
I did use stand-offs. I used the stock thermal pad that comes with the retail processor/fan for the first motherboard and I used Tuniq TX-2 when I moved the CPU to the new motherboard. The GPU does require power... but I didn't even use it on the second motherboard... just trying to get it to post first.
So I replaced the CPU and everything works. Now I just need to figure out what may have caused the problem so it doesn't happen again. I don't think it is safe to just assume the CPU "went bad" on its own after working for 5 days.
I do have another symptom that may be related. If I touch the front part of the case with an electrostatic discharge, the system will immediately reboot. The most sensitive item is the on/off button. If it receives even the slightest, imperceptible ESD, the system reboots. My theory right now is that ESD must be traveling through the front control wires to the power and reset headers of the mother board causing it to reboot. Has anyone experienced this before or know what the problem might be?
One other thing to note, after a reboot caused by an ESD, if I turn off the computer and turn it back on, the next time it posts it starts making the same continuous whining (more like a high frequency buzz) noise that happened when I noticed the original failure. I don’t know what this sound is supposed to indicate, it must be some sort of warning coming from the motherboard, but I can’t find any documentation about it.
I solved the ESD reboot issue by disconnecting the reset button from the reset header. Easy enough.
The buzzing turned out to be a mobo warning that a system fan failed. I setup the BIOS to "WARN" on a failed system fan. For some reason, when I quickly restart the system after turning it off, the fan connected to the SYS1 FAN header doesn't spin up and the warning buzzer sounds. Not sure why the system fan doesn't spin up, but at least I know what it is now.
This also explains the original buzzing I heard when the CPU failed. I turned on the BIOS "WARN" for CPU overheating.