Randall R Schulz wrote:
Greg,
On Wednesday 18 October 2006 18:03, Greg Wallace wrote:
...
So I check the voltage where each wire attaches to the motherboard, not at the power supply source, is that right?
Yes, that's the idea. But you'd do well to heed the other advice that's been offered, here. It's true that a power supply for a modern computer can put out a lot of amps, and if you cross the probes, you could destroy the power supply. If you system is crowded, and many are, especially in that area where there are often IDE and floppy cables connected, it might be challenging to make solid connections between the multimeter probes and the power supply connector pins. Furthermore, you obviously have to take your eyes of the hardware to look at the meter.
One suggestion I have is to connect the black lead from the meter, to the black wire on a spare disk drive connector. Then use the other lead to poke around the main power connector. This way, you're unlikely to short the meter leads.
Just be very careful. Go slow. Perhaps try to dress the cables before starting to make the vicinity of the PSU connector as free of interference as possible.
You might want to do a little hunting on the Internet to see if you can find some pictures or videos describing this sort of procedure. (Considering that someone posted an in-depth, careful video of how to safely disassemble a MacBook Pro, it wouldn't be too surprising to find such a thing for verifying power supply voltages.)
There are the Scott Meuller books on upgrading and repairing PCs, which cover this sort of thing. Perhaps a local library has a copy. Mine does. http://www.quepublishing.com/promotions/promotion.asp?promo=1626&rl=1