HP 8300: Power cut in the whole apartment when I turn of the power strip

[Pibi81]

Hi. I've bought a used HP 8300 CMT which is a connected to a power strip with surge protector. If I use the pc for a long time, when I turn off the power strip, the safety switch goes on and there is a power cut in my apartment. 

Is there a problem with my computer's PSU or is there any reason why I shouldn't connect my PC to a power strip equipped with surge protection? Thanks.

[joselso]

Please note that it makes a lot of difference if you first shut down the computer by means of Windows operating system and then turn off the power strip;

Or -

you turn off the power strip while the computer is still operating (NOT RECOMMENDED!)

Those two situations can cause totally different levels of voltage spikes/surges affecting your apartment power supply, and they point towards different causes of such spikes.

[Pibi81]

Maybe I needed to specify it. The power cut happens after I shut down the pc completely, then I turn off the power strip. 

[joselso · Accepted solution]

OK, so now you may check if, after shutting down the computer you pull its power plug carefully away from the power strip instead of turning off the switch of the power strip, does this disconnection also cause a power failure?

If yes, my guess is that there is some large capacitor at the input of the pc power supply, that remains charged for some time (seconds, tens of seconds, a few minutes?) after you shut down the pc. A possible remedy may be to wait some time after shutting down the pc before disconnecting/pulling the plug/switching off the power strip power switch.

If, on the other hand, the power failure occurs only when you switch off the power strip power switch, then the strip or its switch may be faulty and probably not the pc power supply.

So I suggest you check carefully what order of activities causes the power failure, to narrow down the list of possible causes.

[Pibi81]

I pulled the plug from the power strip and nothing happened. Then I turned off the power strip and also nothing.

Moreover, I've also tried to keep it plugged and wait a couple of minutes, like you said, and nothing happened again. It seems to happen only when I switch off the power strip immediately after I turned off the pc.

[joselso]

Good. This looks like a promising direction - take your time and let any remnant voltages discharge naturally before switching off the power strip, and so you will prevent voltage spikes due to sudden disconnection.

Also, may be the surge protector safety switch is too sensitive? If you can access its specs you may find out if it suits your setup or it can be replaced by a different model.

If there are other appliances fed from the same power strip you may find it useful to separate them to different power strips, to minimize cross-switching effects.

As you probably know, it is recommended to power personal computers from UPS and not directly from house electricity, to protect the pc electronics from unstable voltage due to nearby appliances.

[Pibi81]

Thanks for the help. I will keep it separated from the power strip, since there are other appliances connected to it.