Member Avatar for Alanrwill

Before i send my PC back, i wondered if anyone has come across this before.
Machine is 'custom' AsusP5N-ESLI Quad core Intel running XP.
Machine appears to shut down as usual through XP - screen blank etc. but the fans are still running and wont respond to 20 secs of holding power button. Then, to restart have to turn off main power then back on at which point it will start normally on the switch.

Any ideas very gratefully received

Alan Williams

ADDED
Have just been searching the daniweb database and it is looking like MB

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  • Latest Post Latest Post by forumdude123

Dani AI

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Good suggestions from and . Below is a short, practical checklist that narrows the fault without sending the system away. Follow the safety notes (power off and unplug before touching connectors; use a meter only if confident).

  • Check Windows power handling first: open Device Manager -> Computer. If it shows a non‑ACPI driver (for XP this is rare on a modern build) then the OS may not be issuing a hardware power‑off. If Device Manager shows an ACPI entry, skip to the hardware tests.

  • Front‑panel quick test: with the machine off, unplug the case front‑panel power switch header from the motherboard and start the board by briefly shorting the two power pins with a screwdriver. Shut down from the OS. If the behaviour changes, inspect or replace the case switch/wiring and the front‑panel header wiring.

  • Isolate PSU vs motherboard: try a known good PSU if available. For an advanced test, measure the PS_ON (green) pin on the 24‑pin connector: PS_ON is held low while the PSU is on and should be released (high to +5VSB) when the board requests power off. If PS_ON stays low after shutdown, the motherboard is likely holding it; if PS_ON is released but the PSU still powers the rails, the PSU is likely faulty.

  • BIOS/board checks: reset CMOS to defaults, check power‑management options (ACPI/Restore on AC Power Loss/Wake settings), inspect for bulging/leaking capacitors and ensure the CPU 4/8‑pin and main 24‑pin are seated.

If the PSU swap rules the supply out, the motherboard is the next suspect.

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Member Avatar for willcomp

Probably either mobo or power supply. Do you have another power supply to test with?

Member Avatar for Alanrwill

Thanks for thoughts, will see whether spareis up to the job

Member Avatar for forumdude123

probably a psu issue or one of the power led connections is messed up.

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