Computer help for a friend

[SXRguyinMA]

posting this for a friend over @ TLZone. Any ideas?


Last night while I was working the computer quite responding - mouse and keyboard did nothing. There was no indication of a problem other than that the cursor stopped moving and the keyboard was also ineffective. I tried a different mouse and keyboard with no luck. In fact, it seemed that the USB ports weren't even powered (optical, corded USB mouse wouldn't light up). Everything else still had power - fans spinning, hdd's spinning, mobo led lit etc.

I went to do a hard-shut down which usually requires holding the power button down for about 10 seconds and as soon as I touched the button the computer turned off completely.

When I attempted to re-boot, I got no video signal to the monitor. The computer would power up as best I could tell (fans, hard drives, mobo led etc), but nothing at all on the screen.

I was sort of desperate as I had just typed a paper that was due at 10 this morning and hadn't backed up yet

I thought perhaps it was a bad stick of ram. I swapped the ram sticks around in every possible configuration with no luck.

I tried the other DVI-out on the video card, no luck.

I removed and re-inserted the video card, no luck.

I tried a different video power connector on the psu, no luck.

Then I got out the laptop and googled the problem. Someone on some forum posted the same symptoms and reported that they got the computer to come back on by unplugging everything, waiting a minute, then plugging in only what was necessary to boot and booting. I figured it was just the power that mattered so I unplugged the power cord, no luck. Out of desperation I tried unplugging everything but the monitor, no luck. Then I tried unplugging everything including the monitor, leaving it unplugged for one minute, then plugged in the keyboard, mouse and monitor. It booted right up. During bootup, it briefly flashed a screen that said "overclock failed"

I saved my paper to a thumb drive, then shut the desktop down properly. Tried to re-boot, same problem, same solution fixed it

The computer has been at the same clock since last spring and is prime stable so that doesn't seem likely the problem. I would think it would at least post. In any event, the asus mobo is supposed to revert to standard settings should an oc be so unstable as to not boot (I've tested this, it works)

Also odd, when the computer screws up, it seems that none of the USB ports have power, but they ordinarily have power as soon as the computer is powered up.

One other strange thing, when I did get it booted, I had a look at the bios settings to make sure nothing had gone wonky. they hadn't. I did notice that hardware monitor was reporting 1.19v for the CPU, but the voltage is set in the bios at 1.36. I don't recall whether hardware monitor has always been wrong or if this is indicative of a problem. Once booted up CPU-Z and Speedfan both show 1.36v. If it really is booting up at 1.19v that would explain a lot, but I've no clue how to verify. Once booted up, it does seem to be 1.36 as 1.19 would be extraordinarily unstable.

Computer specs:
Asus P5K-delux wifi mobo (P35 northbridge, ICH9R SB)
HD4830 GPU (mild OC, tests stable)
E5200 processor a 1.36v and 3.6ghz
4gb of high-end 800mhz OZC ram at 842 and 2.1v (tests stable)
temps (gpu and cpu) all nice and low.
Coolermaster 550W PSU

I figured next I'd try it at stock speeds just for good measure, but beyond that I'm at a loss for diagnostics

[Luke122]

I'd start by removing all hardware except what is essential to boot. Video, ram, cpu, keyboard.

Reset the bios to factory defaults, and try that. I'd also get a PSU tester, and see if the voltages are within range. Next up, I'd also try different ram and GPU.

Goofy issues like this almost always resolve to power troubles.

[SXRguyinMA]

thanks for the quick response! I'll relay that to him and see how it goes. thanks!!

[mDust]

Yeah, I'd swap out the PSU for a different one for testing first. If that doesn't resolve it, I'd be looking for shorts on the mobo itself. I've had coolant drip on components that shorted them out, after drying them off they worked fine...so any kind of short like that could cause circuits to misbehave.

Also, that 1.1Ghz OC could have been slowly killing the processor if it has been running hot for a long time...but that wouldn't explain the lack of power in the USB ports.

[SXRguyinMA]

his reply:


Thanks :bowdown:

I did #1 (remove everything but what's needed to boot) with no luck.

I'd like a PSU tester, but I fear they might be $$$. Also, it would be really weird that unplugging the power cord and monitor would "cure" a psu issue I'd think

I wish I could just build a new machine, but that's not in the budget

I think next up is to try stock bios settings or try a new gpu. I'm sorta suspicious of the gpu because everything but video signal seems ok and the problem wasn't "solved" until I unplugged both computer power and the monitor (perhaps the gpu gets a little bit of power from the monitor connector?).

BTW the computer has been on since early this morning and hasn't messed up yet (but to get it to boot this morning I had to unplug everything, wait, plug back up and boot).

[Luke122]

I paid $20 for my PSU tester.. well worth it for the hassles it has saved me over the years. :) He could also just try a different PSU.. though the GPU swap would be easier to try first. :)

[SXRguyinMA]

more


I was thinking about pulling the mobo out just to make sure nothing has fallen down the backside and shorting out in there. I don't think the processor is hurting from the OC as it stays nice and cool (rarely gets above 50c) and the voltage is not above Intel's published maximum. Still, it is a huge oc in terms of change from stock

[Luke122]

I've seen screws and such fall behind motherboards before, and cause intermittent failure issues.. it can be a bitch to troubleshoot.

I still vote for PSU, and resetting the BIOS to factory. That will return all voltages and clock speeds to stock.

Process of elimination. Everything that it is NOT, is one less thing that it could be. :D

[NightrainSrt4]

I had an issue with an Asus P5N-SLI mobo that sounds similar, no video, powering but not "turning on"/video. I think there was a thread somewhere around here. Unplugging everything and plugging it all back in was the only thing that fixed it, but on reboot it needed it done every time after a period of not being used.

What fixed it for me was putting the rig in a different case. The PSU on mine was fine, but something, somewhere in the case, even though I couldn't see anything that was, was shorting something on the mobo.

Why unplugging/reseating everything worked, I don't know, but it did temporarily. Tossed it in a sturdy case instead of a flimsy one and absolutely no problems since.