Member Avatar for domesis

Okay, so before anyone asks... I HAVE read the sticky at the top of the forum and tried everything possible to no avail.

The story so far: Several days ago I was using my PC as I do without any problems at all, it had been running smoothly as it always does (P4 3GHz, 512DDR, XP PRO, ASUS MoBo - unaware of model, 120G HD). I had just that day acquired a brand new MP3 player which had just then finished charging. It required no installation of drivers so I attached it to its AC adaptor and connected it via USB according to its manual. The instant of connecting my computer immediately lost all power, and has since not been able to start up at all. No fans moving, no HD activity, no beeps and no lights. The MP3 player I have since attempted to use in 2 other computers which it didn't ruin, so I am still unsure whether it was the cause.
The only sign of life in the PC is the motherboard light is on when the power button at the rear is on. Other than that it is stone dead.

Since then I have reset CMOS by removing the CMOS battery for several minutes. I have stripped the PC back to barebones with nothing but the GeForce FX5200 graphics card, 1 512 stick of RAM and MoBo + Processor. Same results.

I have used the power supply in another computer without problems, so it isn't that. I have also used the HD as a slave in another computer which obviously also wasn't the problem (as discovered by bare bones). I have also attempted to power on by using a screwdriver to short the power pins. No dice.

I have ensured that every cable is correctly connected, every card etc is seated properly and every neccessary switch turned on. I am at a loss as to what I can try next. I'm thinking at this point that it looks like either a CPU or MoBo problem which I'll haveto go out and replace, but would like some clarification before I do.

Any help would be greatly appreciated. Thanks.

~Domesis

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  • Latest Post Latest Post by wally_lawless

Dani AI

Generated

Given 's report and 's front-USB short hypothesis, a few focused checks can often isolate a motherboard fault cheaply — and sometimes salvage the board — before buying a replacement CPU or mainboard.

Do a close visual inspection first: look for bulging or leaking electrolytic capacitors, dark or melted plastic around the front-USB header, scorch marks, or a distinct burnt smell. Also scan the area around the USB power traces and the VRM (voltage regulator) section near the CPU. Many boards have tiny surface fuses or resettable polyfuses protecting USB power; a blown fuse there is a common, inexpensive repair.

Try these targeted diagnostics (take standard ESD and mains-safety precautions):

  • Verify +5V standby on the ATX connector (purple wire) with the PSU switched on but system off; check main rails only if comfortable using a meter.
  • Remove all front-panel and front-USB/header cables and test the board out of the case on a nonconductive surface (minimal components: CPU, 1 RAM stick, PSU, speaker).
  • Attach a system speaker and boot; listen for POST beeps (missing CPU/RAM will usually produce beep codes).
  • Inspect/test continuity across any small fuses near the USB header (look for designators like F1 or F_USB); an open fuse often points to a one-way short and is cheaper to replace than the whole board.
  • If available, have a shop bench-test the board or swap in a known-good board to verify the CPU.

If those checks show open fuses, bulging caps, or burned components, a modest repair or a used replacement board is often the fastest, cheapest route. If the board passes the simple tests but still won’t signal power, professional bench testing or an RMA (if under warranty) is the practical next step.

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Member Avatar for wally_lawless

Sounds like your mobo may have been shorted out. I'm guessing you're using front USB ports to connect your player? I've seen it happen a couple of times, especially with cheap cases where the connectors for the front USB ports aren't labeled correctly or at all and connecting a device has shorted out the board.

You mentioned that the light is on on the mobo, what colour is it? If it's red or orange that's pretty much a sure sign your board is done, if it's green there's still a chance, sometimes.

If your CPU was dead your board would still fire up when you short the pins, it would just beep a POST failure. From what you've said so far sounds like your mobo is toast, sorry to say.

Member Avatar for domesis

Yeah, it was the front USB port. The light on the MoBo is green, but I get the same result from shorting the pins as with attempting to start normally. ie nothing. So yeah... it is sounding like my motherboard as suspected. Just far better to be sure than to go out and buy another and still be at square one.
Thanks.

~Domesis

Member Avatar for wally_lawless

Well, I've never heard of a computer store that wont let you return something if it doesn't fix your problem.... That is as long as you don't fry the new one as well....

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