PSU and motherboard with power but not power butto

  scopio 23:11 02 Jul 2018

Just had a bit of a scare with the pc. We had a flicker on the electricity all along the road which turned off the traffic and the petrol stations pumps. We had the same yesterday and it used to occur quite frequently about four years ago but very rarely now. Anyway it turned off my pc and when I pressed the power button to power on again it wouldn’t work! Checked the power supply light and it was on. So I took the side panel off and I could see that the motherboard reset button had the light on but the fans were not turning and neither were the HDDs’. Tested the USB ports with the laptop stand which has two fans and the USB ports had power. I could not understand how some parts had power but the HDD, the fans and the pc power button did not! Can a techie please explain how some parts had power but not others?

  Taff™ 09:16 03 Jul 2018

It's all to do with the "Power Rails" from the PSU. If you look at the label on a PSU you will see various Voltage "Rails" or values. The PSU may be fried by the power surge but still providing power through some "Rails".

Obviously in your case not all of them. Get the PSU tested by a local Repair shop. They might simply be able to test it by plugging in a seperate PSU alongside yours and making the connections.

Hope that helps

  scopio 11:42 03 Jul 2018

Thanks Taff, I did eventually unplugged the power cord from the psu for a few seconds and plugged it back and everything went back to normal.

Today when I first powered on the pc Windows flashed a BSOD saying that it was collecting some information and that it would start the pc again. Which it did and all is working fine again.

These sudden electric faults some where outside our control do play havock with the pc.

  Taff™ 12:40 03 Jul 2018

I trust you have it on a high rating Power Surge Unit?

Thanks for the update by the way. Another good trick to discharge capacitors is unplug the Power Cord to the PSU and press and hold the power button for about a minute. Then plug in - sounds like that's what you achieved anyway!

  scopio 12:46 03 Jul 2018

Yes all devices such as the pc, printer, router etc. are connected to a RHOpoint surge guardian.

  wee eddie 12:57 03 Jul 2018

Definitely need an UPS How to select

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