Something strange... Not in the neighbourhood!

  midian 10:15 18 Jan 2018

2 days ago, I upgraded my Ryzen 1600 to the 1800x. As my case is huge and very heavy (Coolermaster Cosmos II) I decided to swap the CPU's with the case upright and still plugged in. As I was about to lower the arm to lock the 1800x into place, the pc turned on, and my initial reaction was like having an electric shock (I wasn't actually shocked) but I instantly moved my hands away and I wont repeat what I said... This has never happened before and I was just wondering if this is a common occurrence and what the cause might be.

  qwbos 10:27 18 Jan 2018

still plugged in

That would be the clue. Before any work in a PC, switch off, unplug from mains, push start button for 30 seconds.

Did you damage your new CPU?

  midian 10:48 18 Jan 2018

The 1800x is running like a dream. Hard to believe I've been building pc's for years... Would have thought id learn my lesson by now.

  Fruit Bat /\0/\ 16:17 18 Jan 2018

If its still plugged in and switched off at the mains there is still a small trickle of power through the motherboard.

Never a good idea to swap components unless switched off at socket can be left plugged in as this can help earth the machine.

However this doesn't work with washing machines, had one throw me across the kitchen even though socket was off.

  MJS WARLORD 17:57 18 Jan 2018

hi midian glad to see you got away with it , fruitbats comments are spot on , when my pc is turned off there are still lights on the mobo , the latest generation of mobos draw power all the time effectively sending power to your usb;s all the time so you can use the pc to charge a phone , fitbit or tablet even when pc is turned off. I did not realise this was happening until I left a set of head phones plugged in and the " show off " lights on them were still working.

  alanrwood 18:35 18 Jan 2018


If its still plugged in and switched off at the mains there is still a small trickle of power through the motherboard.

  alanrwood 18:39 18 Jan 2018


If its still plugged in and switched off at the mains there is still a small trickle of power through the motherboard.

Sorry but I don't understand your logic here. If it is switched off at the mains then there is no supply of power to any component in the computer. I think you are referring to the charge maintained on the PSU smoothing capacitors which can take many minutes after switch off to dissipate and can maintain the M/B LEDs etc for a period but once this has finally dissipated then there is no M/B activity whatsoever as far as I know.

  Fruit Bat /\0/\ 18:45 18 Jan 2018

That should have read switched on at mains and off at PC power switch. :0)

  qwbos 21:36 18 Jan 2018

Fruit Bat/0\/0\

Our ancient tumble dryer has a big juicy capacitor in it. It may have been something similar in your washing machine that bit you.

I always remember how my physics teacher, who'd been involved with radar development during WW2, explained how they left charged capacitors on the shelf contacts up, so that anyone casually picking them up with their palm across the top would get a surprise.

  alanrwood 10:38 19 Jan 2018

Yes I remember that too. In fact in the larger ground radar systems there was a thing called a debo**ocker" stick which was used to ensure that capacitors were discharged before working on the equipment.

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