I'm upgrading my PC from a 650W power supply to a Great Wall 1250W unit. The new PSU uses a round, nonstandard-looking wall power connector, and the seller told me I could reuse the power cord from my old PSU. That cord is labeled 125V, but the computer shows no signs of power after the installation. I tried both positions of the rear power switch and don't see a voltage selector. Could the power cord be the problem, or is there something else I should check during the installation?
3 Answers
Before reinstalling everything, you can test the PSU outside the case using the manufacturer’s approved procedure, such as a PSU tester or the proper power-on jumper on the 24-pin connector. If the PSU does not start with the correct test, it may be defective. If it does start, recheck the motherboard power connections and the case’s front-panel power-switch wiring.
The exact model number matters, since different power supplies can have different input requirements and connectors. The 125V marking on the cord is only its maximum voltage rating; the cord itself doesn’t regulate voltage. If it powered your old system, it’s probably not the cause. Check that the PSU’s rear switch is on, then verify the 24-pin motherboard connector, CPU power connector, GPU power cables, and front-panel power-switch cable.
I tried both switch positions, but I don’t see any voltage-range selector on the unit.
Do not reuse modular PSU cables from the old power supply unless the manufacturer explicitly confirms they are compatible. The connectors may fit while having different pinouts, which can damage components or prevent the system from starting. Use only the cables supplied with the Great Wall unit. Also, make sure the round wall-side connector is fully seated and that the PSU is rated for your local electrical supply.
The specific model number would help confirm the correct connector and testing procedure, since simply calling it a 1250W unit isn’t enough to identify it.