How to drain the mobo & psu capacitors?
Posted by DarkDiver88@reddit | buildapc | View on Reddit | 1 comments
I'm using a Gigabyte Z390 Designare Mobo with a 9900k CPU and a Corsair AX1200i PSU.
I'm currently troubleshooting a BIOS update reboot loop issue and I noticed that leaving the pc for 12 hours or so (1 hour doesn't work) with the PSU power switch off, while keeping the power cord plugged in, let's windows 10 start correctly without going into reboot loops.
I now want to shorten that time in order to try a different BIOS version and always waiting 12h until you get another try is a bit much.
I already tried turning off the PSU power switch, then unplugging the power cord and then pressing the pc power button for about 60 seconds (also tried it with multiple pressings of the power button), but it does not lead to the same startup behavior that I get after the 12h procedure.
Does it have to do with the plugged in power cable during those 12h (I only turned off the PSU switch)? Can I turn off the PSU and leave the power cord plugged in and then press the power button for 60 seconds? Would this damage any components?
Is there any other way to shorten this 12h process? Does anything else happen during those 12h than capacitor drainage that I can't recreate with holding the power button on for a few seconds?
Active-Banana-1221@reddit
Shot in the dark, but the large capacitors in a power supply can (depending on the capacitor) potentially hold a charge for several hours when not under load, some can hold a charge for several days or longer. One method I have seen done to eliminate residual charge is to unplug the power supply from the wall and short the 24 pin ATX main board power cable for at least a few minutes, up to half an hour to be safe. You can do this by jamming a pair of tweezers into pins 4 and 5 on the top row (counting from left to right, with the connector's lock pin facing up) to bridge them together, effectively jump starting the PSU and forcing it to continuously discharge. I'm not sure if this would solve your problem but it is a pretty surefire way to quickly and effectively discharge PSU capacitors.