Changing fan on the PSU
- Thread starter Druga Runda
- Start date
Here's my opinions. They are not facts, and do not treat them as such:
I'd have thought the motherboard will discharge low-voltage power supply caps pretty much as soon as the power's switched off. There's no relays inside a power supply to physically disconnect the caps from the network, which is what would be required to prevent leakage discharge. I'd have thought.
Of course, this is a switch-mode supply, which may also have HV-side caps. I'd have thought the same would apply to them, but I'm not sure.
Most modern power supplies have integral switches anyway, but I wouldn't have thought there would be any problem yanking the plug out on the BIOS screen either - compared to a switch, that is. Power switches are not magic. They still arc exactly the same as a plug-yank would.
I'd have thought the motherboard will discharge low-voltage power supply caps pretty much as soon as the power's switched off. There's no relays inside a power supply to physically disconnect the caps from the network, which is what would be required to prevent leakage discharge. I'd have thought.
Of course, this is a switch-mode supply, which may also have HV-side caps. I'd have thought the same would apply to them, but I'm not sure.
Most modern power supplies have integral switches anyway, but I wouldn't have thought there would be any problem yanking the plug out on the BIOS screen either - compared to a switch, that is. Power switches are not magic. They still arc exactly the same as a plug-yank would.
Whoah, there sure is a whole lot of do-this-no-wait-that's-stupid going on... 
Let's not mystify PSUs, shall we? Just shut down the machine like normal, switch off the unit, disconnect the power cord, and take off the casing. You'll only be un-, and replugging a simple fan connector, not licking through the whole circuitry or something.
Afraid of caps? DON'T TOUCH THEM. If that's too difficult, you should just go out, buy a new PSU and be done with it.
Let's not mystify PSUs, shall we? Just shut down the machine like normal, switch off the unit, disconnect the power cord, and take off the casing. You'll only be un-, and replugging a simple fan connector, not licking through the whole circuitry or something.
Afraid of caps? DON'T TOUCH THEM. If that's too difficult, you should just go out, buy a new PSU and be done with it.
I don't understand the issue people are having with unplugging the cable while the PC is on... The worst thing it can happen is, if you "wiggle" (right term?) the plug while doing it the board will turn on/off many times in a short while (I've always heard that's a bad thing). If you're really worried about it, just use the switch on any decent PSU. It works the same way as if you disconnect the power cord.
Any EE that can explain a better method of draining the caps? YeuEmMaiMai has given the most plausible solution yet, IMO.
Any EE that can explain a better method of draining the caps? YeuEmMaiMai has given the most plausible solution yet, IMO.
Damn, you fools are making a ruckus out of nothing.
Unplugging the power cord when the computer is on is EXACTLY the same as if you turned off the master power switch on a surge suppressor OR when there's a power outage OR when the circuit breaker cuts in....
IT WILL NOT HARM YOUR COMPUTER DAMIT!!!!
BTW if you're afraid of pulling the plug while in POST, then use a friggen DOS BOOT FLOPPY!!!!!
Friggen morons!!!
PS regarding the HDD, well like someone already said all HDD have a autopark feature, however, if you're really paranoid then go into the BIOS and turn on the HDD power down option and set it to 1 minute then boot into DOS and just let it sit there until the HDD powers down then pull then plug.
The other way to discharge the HV caps is to use a ceramic resistor...
Reasons to use a resistor and not a screwdriver to discharge capacitors:
1. It will not destroy screwdrivers and capacitor terminals.
2. It will not damage the capacitor (due to the current pulse).
3. It will reduce your spouse's stress level in not having to hear those
scary snaps and crackles.
Unplugging the power cord when the computer is on is EXACTLY the same as if you turned off the master power switch on a surge suppressor OR when there's a power outage OR when the circuit breaker cuts in....
IT WILL NOT HARM YOUR COMPUTER DAMIT!!!!
BTW if you're afraid of pulling the plug while in POST, then use a friggen DOS BOOT FLOPPY!!!!!
Friggen morons!!!
PS regarding the HDD, well like someone already said all HDD have a autopark feature, however, if you're really paranoid then go into the BIOS and turn on the HDD power down option and set it to 1 minute then boot into DOS and just let it sit there until the HDD powers down then pull then plug.
The other way to discharge the HV caps is to use a ceramic resistor...
Reasons to use a resistor and not a screwdriver to discharge capacitors:
1. It will not destroy screwdrivers and capacitor terminals.
2. It will not damage the capacitor (due to the current pulse).
3. It will reduce your spouse's stress level in not having to hear those
scary snaps and crackles.
