How Normally Do You Drain The Computer Of Electricity When Working On It

How normally do you drain the computer of ecectricity. I have done the recommended steps of shutting down the computer, disconnect the power cord going to the computer and wall outlet, press power switch on the back of the computer to off. Making sure there is no power going from the power supply to the motherboard.

Now some say at this point you press and hold the power for 10 seconds some say 30 seconds some say you press the power 3 times. This is to discharge any static electricity on the motherboard and drain the caps.

But I'm confused if you have to press and hold the power or press 3 or 4 times or more and for how long.

I don't want to be working if the motherboard and caps still have some static electricity and this causes a short.

I'm just confuse on the last step as I'm getting different information on what I read.

 

One or the other is fine. The power switch on the back of the computer is the master power switch. Flipping that to Off (0) removes all power from the computer - just as unplugging from the wall does. But unplugging from the wall is the safer method because it does not assume the master power switch is working properly.

Note with the power supply plugged in and the master power switch set to On (1), your computer is really in standby mode and some power (+5Vsb standby voltage) is being applied to several points on the motherboard (including the front panel power button).

Yeah, that's all a bunch of BS! For one it has absolutely nothing to do with static so anyone who says otherwise is clueless.

And pressing the power button does NOT drain any caps either. The front panel power button is really a remote button that ties to a circuit on the motherboard that does NOT have any capacitors to drain. So all pressing on the button does is wear out the button and your finger faster.

I think that old and incorrect myth came from many years ago with the AT Form Factor used on the original IBM PC where the front panel power button was wired directly back to the power supply. But for many years, the ATX Form Factor standard has been used and it uses the remote button to start the computer.

Now some capacitors will retain a charge once the power is removed. But engineers know this so circuits with such "storage" capacitors are designed with "bleeder" resistors with the purpose of draining those caps. And that is done in a couple seconds, not minutes. But there are no capacitors on motherboards big enough to cause any damage anyway. Remember, the highest voltage seen on a motherboard is 12V so that can bleed off very quickly - almost instantaneously. It is only inside the power supply (where deadly voltages exist!) where the caps are large enough to worry about - but again, PSUs are designed to discharge those caps as soon as power is removed.

Now this does assume the PSU is not damaged but unless you are a qualified technician you should not be opening up a PSU anyway.

All of the above is with PCs. With notebooks, you must of course, remove the battery. And with some notebooks, pressing and holding the power button does affect the charging/power circuit (read your manual). But with PCs, holding the power button does NOT discharge any circuits (they don't need it anyway).

HAVING SAID ALL THAT, you do indeed want to discharge any static in your body before reaching inside the case. This is to prevent any static discharge (ESD) from your body zapping and destroying ESD sensitive devices such as your CPU, GPU, RAM and other high density IC devices on the motherboard.

It is important to note you can generate enough destructive static in your body just by squirming around in your clothes sitting on your chair. And the thing about ESD damage is the static discharge can be so tiny we (as humans) may not see, hear or feel it. Yet it is big enough to torch a Grand Canyon sized trench (microscopically speaking) through millions of transistor gates on those sensitive devices!

So it is critical you and your computer be "at the same potentials" before you reach in as that will prevent any static voltage from jumping (arcing).

So how do you do that? Simple. Exit Windows and shutdown your computer. Flip the master power switch on the back of your computer or unplug the computer from the wall. Open the side panel of the case then touch bare metal of the case interior. That's it! You are discharged. Periodically touch bare metal again to keep from building up more static.