Computer power cycles in continuous loop

If your computer is power cycling where it is turning on and then turning off, and then turning back on again, and does this in a continuous loop, this is probably indicative of an issue.

There are a few possible reasons for this behavior and tracking down which is to blame can be a little tricky.

Power Supply

The first thing to check is the power supply. Is it plugged in to the wall correclty? Make sure that all connections to the motherboard are securely fastened. Ensure that the voltage coming out of the power supply is correct. You may also be able to run a “paper clip” test on a desktop power supply in order to test if the behavior happens when the power supply is disconnected from the motherboard. If the power supply is kicking on and off then this is likely the issue causing the power cycling.


If the power supply is working correctly next is to test the CPU. Usually if the computer seems to start to boot, but never gets to the bios screen then the CPU may be the reason. Sometimes the heat sink on the CPU becomes loose or the CPU paste eventually wears out. It is a good idea to check that the CPU heat-sink is securely fastened to the motherboard. Remove the heat-sink and apply new thermal paste.

Motherboard Capacitor

If you have tested the power supply and the CPU and neither seems to be the reason for the power cycling behaivor, then a capacitor on the actual motherboard could be to blame for the behavior. The capacitors can sometimes begin to bulge and burst or bust. When this happens they no longer function correctly and sometime cause erratic behavior such as startup and shutdown loops. Unfortunately this is also indicative that more of the capacitors on the motherboard may begin to fail and probably the entire motherboard would need to be replaced if this is the case.

It may be a good idea to take your computer to a computer repair store near you to have these tests performed. The expert computer repair technicians at South City Computer will perform these tests and give you a report for how to fix this issue. Contact South City Computer today to get started.

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