Quote:
Originally Posted by Beest
I found some 600 ohm and 1K Ohm resistors lying around and tried plugging them into the purple wire, also 2 in parallel, no voltage drop.
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As you may have already seen, a defective supply can act good when not connected to a load. That is why the paper clip test says so little useful. That is why power supply testers are almost useless. That is why a power supply is best measured by not disconnecting a single wire.
The 5VSB should output maybe 2 amps (its label may say more). A full load is 5/2 ohms or 2.5 ohms. Radio Shack may still sell 10 ohm 10 watt ceramic resistors. One of those might be easier to use than four 100 ohms in parallel (25 ohms).
5 volts divided by 10 ohms is a half amp. If the 5VSB is defective, then a half amp load should cause some voltage reduction.
If those 10 ohm resistors are sold in pairs, then two ten ohm resistors means a full 1 amp load. A great test of the 5VSB. Those two 10 ohm resistors (that will get hot when held) should not cause the 5VSB to drop. If 5VSB does drop, the PSU's 5VSB (and not anything in the PC) is defective. That is a definitive and "you have found the problem" conclusion.
5 volts divided by 25 ohms (four 100 ohms in parallel) is 200 ma. Not a great load. But enough that can be purchased cheaply. The ten ohm ceramic would be better but I don't know if it remains available.
600 ohm or 1k ohm resistors are only 10 milliamps (only one LED) or 5 milliamps (less than 1 LED). Virtually a near zero load.
If the PSU 5VSB does not drop with that load, then the problem (excessive load) is probably located on the motherboard.