PSU dismantling - what do I need to be aware of?

[artoodeeto]

Subject line says it all - I want to take my PSU apart and custom mount the innards & fan, but I know just enough about them that their capacitors can hold quite a charge. Since I don't really want that charge transferring to me, what sort of precautions should I take before dismantling it? It's a Thermaltake Toughpower 650W w/modular cables. thanks!!

[Technochicken]

Most PSU's will probably have a circuit to bleed the charge from high capacity capacitors while they are not being used, but just in case, you should probably discharge them before handling the innards. This can be done by simply connecting the two leads with a screwdriver, but I have read that that can possibly dangerous. What I do is connect the two leads to a high wattage resistor, and let it sit for about a minute.

[artoodeeto]

thanks! now to go find a high-watt resistor (all I have right now are 1-ohm). Radio Shack, here I come....

[Technochicken]

Just for a reference, the one I use is a 5k ohm, 75 watt one made by Ohmite. This is probably overkill, but I have it, so why not. Something in the area of 10-25 watts, and 5k ohms or more should do just fine for the large capacitors in the PSU.

[slaveofconvention]

I've also heard of the following method, but can't personally vouch for it - turn on the pc, or a pc with the PSU connected to it, and enter the bios to prevent it loading into windows or your OS of choice, then pull the power cable out of the back of the PSU without turning it off at the wall, the PSU or the PC - apparently this causes the caps to drain themselves into the PC (harmlessly)

[nevermind1534]

^That's what I do. It works very well. Otherwise, most PSUs will be drained after around 30 seconds to a minute, especially if the mobo is plugged into it.

[artoodeeto]

I've also heard of the following method, but can't personally vouch for it - turn on the pc, or a pc with the PSU connected to it, and enter the bios to prevent it loading into windows or your OS of choice, then pull the power cable out of the back of the PSU without turning it off at the wall, the PSU or the PC - apparently this causes the caps to drain themselves into the PC (harmlessly)

that actually makes perfect sense - since the computer doesn't exactly have any kind of sensor to tell it when you've yanked the wall power.
I've had the PSU disconnected from the wall (and the master switch turned off) but still plugged into the motherboard since yesterday morning. I take it then it should be totally drained now? Or do I need leave it connected to the m/b, flip the master power switch back on (without plugging it in to the wall) and wait a few minutes?
I'm very interested to see how much of the PSU's weight is its case and how much is the PCB/heatsinks and other innards...

[nevermind1534]

The way you have it right now should be fine, especially if it's a name brand PSU.

[artoodeeto]

sweet. If you don't hear from me within a few days, either I've zapped myself or the PSU.
I figure even if I decide it's not worth the effort to dismantle (depends mostly on internal space in the case), from looking at a similar thermaltake PSU taken apart, it looks like all the "hardwired" cords just plug into a PCB board, which is good news for me - I'm not using the hardwired 6 pin PCI-E cable. Be nice to get it out of there.

[mofo]

I call dibs on the sandcrawler...

Space prohibiting, the psu naked in the assembly bay could provide a nice backdrop to the droids scattered about. It would still look great even behind a thin plastic sheet.