Power Supply Problems: No Power, Load Shutdowns, Noise
Never open a power supply. It stores dangerous charge even unplugged. This covers external checks only.
Nothing happens when you press the power button
No fans and no lights means either no power or the start signal is not reaching the PSU.
Read this if you searched:pc will not power onpower button no responsejump power switch pinstest psu
- Check the switch on the back of the PSU is set to 'I'.
- Try a different wall outlet and a different power cable.
- Disconnect the case power button header and briefly short those two pins with a screwdriver. If it starts, the button or its wiring is at fault.Tool: A screwdriver
- Confirm both the 24-pin and 8-pin are fully seated with the latch engaged.
Sudden shutdown under heavy load
The protection circuit is cutting power. This happens even at apparently adequate wattage, because GPUs draw brief spikes far above their rating.
Read this if you searched:psu shutdown under loadgpu daisy chain cableatx 3.0 spikes
- Check the GPU is not powered through a single daisy-chained cable. A GPU needing two or more 8-pins should use separate cables.→ Splitting onto separate cables resolves many cases.
- Limit the GPU power to 80% and retest. If it stops, the PSU lacks headroom.
- Check the PSU's age. Beyond about five years, internal ageing reduces usable headroom.
- If possible, temporarily swap in a higher-capacity PSU. This is the definitive test.
High-pitched whine (coil whine)
Components vibrating audibly. Usually not a fault. But stop immediately if accompanied by a burning smell.
Read this if you searched:coil whinepsu buzzingburning smell pc
- Check whether it tracks load. Noise only under load or at very high frame rates is coil whine.
- Cap the frame rate and see if it quietens; whine is common at several hundred fps.
- A burning smell or scorch marks means stop and unplug immediately. That is not coil whine.