MAC SE instability and floppy issues

hello all, I have an original Mac SE here, which seems to be giving me lots of trouble. so far im in a new mobo, CRT (I let the magic gas out of the original one, second SE ive done that to!) SCSI and floppy cables, and floppy drive. the weirdest thing happens to it, and right now, im looking at power supply failure as the next logical guess. my problem is, I try to boot up my mac from either internal or external floppy, but regardless of which it is, it will read the disk, and on restart the floppy disk will be corrupted and will need to be reimaged. second, no matter the hard drive I put in it, the mac either will not see it, or it will go through, initialize, then at the end a dialog box will flash really fast on and off, and the computer I/O will lock up while doing this. the other thing that makes me think it is PS failure is the fact that one time i hooked the hard drive in to power while it was running, and when I did so, the fan speed bogged down significantly on spin-up of the drive. is there anyone with pinouts of this PS i can use to test it, or any advice as to what failure points I should check first? I tried google (they say its our friend...) and I get no info as to the voltages of the logic board connector or the like. any help is most appreciated!! thanks