If you have that Sony CR44 out of the Mac, make sure you give it a decent load to get reliable voltage readings. I was only pulling 0.1 amps from the +5 rail and it caused low outputs on two other rails. I gave that +5 a much bigger load and everything was OK. Here's my before/after. Unfortunately I didn't have power resistors laying around that let me do a little more than 0.1Amp. I had to go way higher, as you'll see LOL.