PC powers off but mouse & laptop still lit

  Joe G 11:19 30 Nov 2011

A strange thing happened the other day. My PC switched itself off and I couldn't turn back on - though the mouse & keyboard were still illuminated. I eventually tried a different socket and the PC powered up ok - can anyne explain this?

  lotvic 12:28 30 Nov 2011

Confused, is it a laptop or a tower pc?

When you say "PC switched itself off" do you mean the monitor went blank and into standby and was there a message saying 'no signal'? If so then it could be a loose lead from monitor to pc (if it is a tower pc with separate monitor)

If it wasn't that then please give more details of what happened and your setup (also say what Op Sys - XP, W7?)

  Joe G 12:48 30 Nov 2011

Thanks - sorry I should have been clearer!

Its a tower - running XP - went completely dead - no fan running no output to video. Yes it was the power socket I changed - I just thought it odd that when it did go off some power was obviously coming through to mouse & keyboard

  Batch 15:14 30 Nov 2011

Are the mouse and keyboard USB connections?

If so, maybe it had gone in to some sort of standby. I've noticed that there's still power on USBs (at least sometimes) whilst in standby, even though the PC is in a very low power state (e.g. no fans / video output, similar to as you have described)

  Joe G 17:23 30 Nov 2011

The mouse may be but the keyboard is a standard connection - sounds like a possibility though

  T0SH 11:46 01 Dec 2011

Desktop pc`s atx power supplies do not completely shut down unless the power supply is disconnected, whilst the power is connected they go into a standby state where it still outputs a low voltage 3.3 volt DC, this is needed to power up the system start up buttons on the case and on some multifunction keyboards it also allows the mouse button to wake up the PC from a sleep/hibernation or standby state it is also supports wake on lan or modem ring if these are enabled

So all in all this is normal

Cheers HC

  Joe G 20:47 01 Dec 2011

Thanks - that sounds like a good explanation - bit odd though that PC started up when I plugged it into a different mains socket if there was still power coming through the cable when plugged into the other socket where the PC wouldn't work - or does the PSU recognise that the PC is plugged in some other way than through an electric signal

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