I think I have a problem with my computer that might be caused by my Coolermaster UCP 700W Power Supply. I found out that when I plug out the CPU 4+4 Pin Connector, the lights and fans come on and everything seems fine. However when I plug it back in, the computer will automatically switch off just a split second after I switch it on. It will happen continuously until I cut the power. Once I cut the power, the same thing would repeat once more but this time, the faulty indicator light at the back of the UCP 700W power supply will blink once after it switches off(white light). I do not know what it means because the codes/signals are not written in the manual nor mentioned on coolermaster.com
Could my power supply be faulty? Or is this a sign of CPU failure?
You can sort of check the PSU. Try to borrow a known good PSU of similar power capacity. If you cannot do that, use a DMM to measure the voltages. Measure between the colored wires and either chassis ground or the black wires. Yellow wires should be 12 volts. Red wires: +5 volts, orange wires: +3.3 volts, blue wire : -12 volts, violet wire: 5 volts always on. Tolerances are +/- 5% except for the -12 volts which is +/- 10%.
The gray wire is really important. It should go from 0 to +5 volts when you turn the PSU on with the case switch. CPU needs this signal to boot.
This checks the PSU under no load conditions, so it is not completely reliable. But if
it can not pass this, it is dead. Then repeat the checks with the PSU plugged into the computer to put a load on the PSU.
hi all of everything I found out it was due to a faulty cmos battery. It's hard to think that it was the cause because it is such an unusual problem. In fact only one of two batteries from two of my other computers worked. Thanks for your help anyway, you guys are great.