Discharging a PSU Capacitor

[adamfelker]

I'm thinking of changing the fans on my PSU to L1A's, but I'm afraid of serious injury. I was wondering what the best way to discharge the capacitors before I begin working on the PSU. One person I talked to suggested taking a plugged in extension cord and touching the grounding pin to each capacitor. Would this work? Could it damage the PSU? Any advice would be very welcome.

 

[SWScorch]

As far as I know that should work. But I am not an electrician so I cant be sure. What I do when I want to work on a power supply is turn off the computer, unplug the power cord and then attempt to boot the computer a few times. This drains the capacitors of their charge, or at least most of it, apparently. I am also very careful and have had no accidents.... yet.

 

[fatbaby]

tap the capacitator with a screwdriver (with rubber grip)

That should discharge it...

DO AT YOUR OWN RISK!

 

[ShinSa]

Discharging capacitors isnt a hard thing to do. Simply turn off your computer and leave the power supply connected to the outlet. The middle prong acts as a ground to the PSU and after a few seconds, the caps should be discharged.

Another way is to just let the PSU sit for couple of minutes. Static voltage leak will drain all the votage from the CAP. PSUs are harmless really.

Touching a cap with a screwdriver doesnt do anything. Cap's exterior is insulated.

This has been covered before in a previous thread.

Link

 

[LS20]

i put L1a in my psu box... just becareful not to touch the thing. i tried to avoid it and got the fan in there just fine

 

[Jeff7]

I've put fans in PSU's quite a few times without discharging the caps. Things to do: never put both hands in the thing at once - that way if any fingers touch contacts, the current will more likely go through your hand, not through your heart.
And other than that, just don't touch anything except insulated wires. If you need to pull something and you might slip, well, find another way of doing it. I haven't had a problem yet replacing PSU fans.

 

[MassiveUnit]

Just FYI, capacitors can retain their charge for a LONG time after the power has been turned off. Take a fairly big (100K or so) 1/2 watt resistor and hold it by the brown part with a pair of pliers. Touch the wires of the resistor to both of the pins that came out of the capacitor and are soldered to the ps board (they will be underneath). the only problem with this, is it defeats the purpose of discharging the capacitor in the first place, because you have to take the board off of it's mounting within the power supply to get at the contacts. All you have to do is be a little careful and use a little common sense. The capacitor discharging on you is not that big of a deal, even if is 220V, because it won't kill you. As long as you don't have the power supply plugged in and you are not talented enough to touch one prong of the capacitor with one hand and one with the other, you will be fine and even if you do touch it, it will surprise you more than anything.