Member Avatar for Agsmith2k6

I have a computer that i have built and upgraded and it has been a work in process for some time. About 2 weeks ago i had an issue in which my motherboard would not boot at all. I RMAd the motheboard, received a new one and am now having more troubles.

Firstly, upon reassembling the barebones of my system the Computer would start as soon as I flipped the PSU on, it did not wait for the power switch to be activated. When the system booted under these circumstances however, it was unstable and not all of my fans would run at once.
I went for a walk around my house and upon comming back inside less than 15 minutes after this problem i found that i received no response what so ever when trying to boot my computer, I cannot get it to POST and i can not even get any signs of life aside from the motherboard LED being on. PLZ PLZ post if you hae any idea as to what component may be at fault or have any idea as to what is wrong.

COMPONENTS

MOBO: Asus a8n32-sli Deluxe
PROCESSOR: Athlon 64 3700+
VIDEO CARD: ATI Radeon X1850 GTO2
RAM: 2gig Mushkin dual channel

I also have 2 IDE hd and 1 SATA Raptor. However i have not even connected these because i can not even get system to POST.

Please help......... im desperate...

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  • Latest Post Latest Post by JANINE

Dani AI

Generated

Quick, focused checklist to isolate PSU vs motherboard and rule out simple wiring/shorts. Since the board was RMA'd and a new CPU installed, start with a minimal "bench" test and eliminate the PSU and case wiring before assuming another bad motherboard. As suggested, check the front-panel wiring; as suggested, try alternate RAM/video. Note that the OS (Vista) cannot affect power behavior before POST, so 's Vista comment is not relevant at this stage.

  • Prepare a minimal bench system: power supply, motherboard on a non-conductive surface, CPU + cooler, one known-good RAM stick in the recommended slot, required GPU (if no onboard video), 24-pin ATX and 4-pin/8-pin CPU power connected, and a system speaker attached. No drives or extra cards.
  • Test the power switch wiring: disconnect the case power-button cable and momentarily short the two power pins on the motherboard with a screwdriver; if it boots, the case switch/wiring is bad.
  • If the board still powers instantly when PSU is turned on (with front-panel disconnected), suspect the PSU. Swap in a known-good PSU if possible.
  • If no spare PSU, test the PSU alone: unplug from components, jump PS_ON (green) to ground (black) to start it, confirm fans spin, then measure rails with a multimeter. Expected tolerances: +12V (~11.4–12.6V), +5V (~4.75–5.25V), +3.3V (~3.135–3.465V). Take caution around live voltages.
  • Eliminate shorts: remove motherboard from the case and boot on a cardboard box or motherboard tray. Check that only the proper standoffs are fitted and no screw or metal is contacting the PCB.
  • Clear CMOS (jumper or remove battery briefly), reseat CPU and RAM, try a single DIMM, listen for beep codes and compare to the manual.

If a known-good PSU lets the board POST, the original PSU is guilty. If a good PSU fails to POST on the bench, document LED/LED blink/beep patterns and pursue an RMA for the board.

Recommended Answers

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Member Avatar for lasher511

Sounds like you might not have the cases power switch attached to the mothboard problem. This may not be the only problem with your machine if it shut down however it would account for the powering on when the computer is plugged in and the power button now working.

Member Avatar for Agsmith2k6

i have deffinately double and triple checked the jumper configuration and made sure that my power switch is connected properly, as well as my restart switch HDD Led Power Led etc. Could this possibly be a power supply related issue or do you think it is MOBO related.....

I find the later of the two options less likely merely because i have just received a RMA mobo. ALSO i have just purchased a brand new processor. This leaves the only options as being PSU, or possibly a faulty RMA mobo.

Any ideas?

Member Avatar for cguan_77

hi agsmith,

try using other RAM and check your video card also...

Member Avatar for JANINE

Hi agsmith, welcome to daniweb

This problem sounds like there maybe something more sinister going on it there. It seems as though it is possible that there maybe a wiring problem such as a short circuit somewhere either within your PSU or Motherboard.

However... let me ask!!!! What operating system are you running? If you are running vista I can say from experience that Vista does not like PSU's with rocker switches. It has a habit of turning these on. The only way out of this is to turn off the rocker switch at the back of the PSU

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