Power Supply Unit Repairs

Safety warnings

• A no-power condition does not prove that the PSU has failed.
• The mains socket, mains cable, PSU switch, motherboard, front-panel power switch or another component may be responsible.
• Do not open the PSU to investigate.
• Do not touch internal PSU components or terminals.
• Do not attempt to discharge PSU capacitors yourself.
• Do not repeatedly force a suspected failed PSU to start.
• If there has been smoke, burning, popping, arcing or melting, stop using the equipment.

Important: Random shutdowns and restarts can be caused by PSU protection, overheating, motherboard faults, CPU/GPU faults, RAM problems, unstable settings, cabling or mains power. Replacing the PSU without diagnosis may not resolve the fault.

Do not repeatedly stress-test a system that is unexpectedly losing power. Continued operation after an electrical fault can create additional hardware risk.

Fan warning: Some modern PSUs use semi-passive or zero-RPM fan modes and may intentionally stop the fan at low loads. A stationary fan therefore does not automatically mean the PSU has failed.

Stop-use warning: Smoke, burning smell, popping, arcing, scorching or rapidly increasing heat requires the PC to be switched off and disconnected from mains power if safe to do so.

Never continue using a visibly melted, scorched or heat-damaged connector. A damaged connection can create high resistance, heat generation, arcing and further damage.

Do not repair damaged high-current PSU connectors with improvised wiring, household connectors or unapproved adapters.

12VHPWR / 12V-2×6 safety: The connector must be fully inserted and securely seated. Follow the GPU and PSU manufacturer’s installation requirements.

Do not sharply bend a high-power GPU cable immediately next to the connector. Maintain the clearance and bend guidance specified by the relevant manufacturer.

Do not use damaged, loose, melted or visibly overheated high-power GPU connectors.

Wattage alone does not establish PSU suitability. Connector requirements, PSU topology, transient response, CPU and GPU requirements, physical dimensions, efficiency, platform design and manufacturer specifications can all matter.

A higher wattage PSU is not automatically compatible with every PC. The required connectors and physical and electrical compatibility still need to be checked.

Do not use a visibly damaged mains cable, plug, socket, extension lead or power strip. Mains electrical faults can present serious shock and fire risks.

Do not bypass earth connections or use unsafe mains adapters. The protective earth arrangement must not be defeated.

If you suspect a household mains fault rather than a PC fault, contact a suitably qualified electrician rather than attempting electrical work yourself.

PSU protection activating can be the PSU doing its job rather than proof that the PSU itself is defective. A short circuit, failed component, excessive load or another hardware fault can trigger protection.

Do not repeatedly bypass or defeat PSU protection circuits. Protection systems exist to reduce the risk of damage to the PSU and connected equipment.

STOP USING THE EQUIPMENT. If smoke, burning, arcing, popping, scorching, melting or an electrical flash has occurred, switch off and disconnect from mains power only if this can be done safely.

Do not open the PSU to find the source of the fault. Internal PSU components can remain electrically hazardous after the unit is disconnected.

Do not reconnect a PSU that has produced smoke, flames, significant arcing or a strong burning smell simply to see whether it works again.

CRITICAL: Modular PSU cables are not universally interchangeable. Two cables can physically fit while having different electrical pinouts.

Never mix modular cables from different PSU brands or models unless compatibility is explicitly confirmed by the manufacturer. Incorrect cabling can cause immediate hardware damage.

Do not rely solely on the connector shape or the fact that a cable physically fits.

Do not connect a PSU cable simply because the connector appears to fit. CPU EPS, PCIe, motherboard and other connectors have different purposes and electrical arrangements.

Do not use improvised adapters or force connectors into sockets. If a connector does not fit correctly, stop and establish exactly what the connector is intended for.

A new-build no-power condition can originate from the PSU, motherboard, CPU, RAM, GPU, front-panel wiring, storage, cooling or another component.

Paperclip and basic PSU tester results do not prove that a PSU is healthy under real system load. They can provide limited information but are not a complete diagnostic.

Do not open the PSU or probe its internal circuitry. Internal capacitors and other components can retain dangerous charge after the PSU has been unplugged.

Do not deliberately short pins, defeat protection circuits or perform improvised electrical tests.

If a PSU has already been opened or incorrectly tested, tell us when submitting the repair enquiry.

Do not power on a PSU or PC after liquid contamination until it has been appropriately assessed. Applying power to contaminated electronics can cause short circuits, corrosion, component failure and further damage.

Do not open the PSU to dry, clean or inspect it yourself. The internal electrical hazards remain even when the unit appears dry.

Liquid-damage repairs are not covered by the standard 40-day labour warranty.

Do not choose a replacement PSU using wattage alone. Physical dimensions, connectors, platform compatibility, GPU requirements, CPU requirements and system configuration must also be considered.

Do not assume an older PSU is suitable simply because its wattage appears sufficient. PSU platform, age, condition, connector requirements and modern system load characteristics matter.

An intermittent fault is not automatically a PSU fault. Motherboards, CPUs, GPUs, RAM, cooling, storage, drivers, cabling and mains power can all produce intermittent symptoms.

Advanced diagnosis may be required where the fault cannot be reproduced reliably or only appears under specific loads or temperatures.