Desktop POST Hardware System: shorted board rail. A capacitor or semiconductor pulls a supply toward ground.

The distinguishing clue

Current draw is abnormal and protection may stop startup.

Checks before an assessment

Record the exact POST light, beep or code and the motherboard model. Check the monitor input externally; do not treat a diagnostic light as proof that a named part is defective.

Stop point: Repeated part swapping with power connected can damage components.

Workshop confirmation and repair

Device-level check: Record codes and test minimum known-good hardware in a fixed order.

Targeted check: Isolate loads and locate the affected rail using controlled measurements. If confirmed: Replace the shorted component and verify resistance before power.

Repair boundary: Repair the confirmed memory, graphics, processor, firmware or board stage.

Related cause to rule out

When fans or lights start but the board never completes initialisation, also consider Desktop POST Hardware System: incorrect power sequence before choosing a repair.

Checks after the work

After repair or replacement, check cold boot, diagnostic indicators, full detection, restart and sleep.

For an AEPC repair assessment in East Auckland, provide the exact model and observed clue. Call 027 908 8880 before visiting the Burswood workshop.