I got a Power Mac G5 aluminium tower to repair. It is the original Dual 2.0GHz G5 from 2003.
No matter what combination of 12 matching pairs of RAM I use (PC3200), I am still getting the 3-flash - pause - three flash code on startup (no chime). This, I discovered means MARGINAL/BAD RAM. All this RAM came from working PCs, so there is nothing wrong with it at all.
I have managed to get a chime, and start booting the computer about 5 times out of 250. I have reached the desktop once, and machine froze when I got info on the hard drive (capacity -- free space --).
I believe this is the power supply failing, or a faulty board, as the OS was crashing mid start-up, or even before. The freezing is also a worry.
Apart from this obvious problem of not getting past the chime on startup, I don't know where to turn. My PC RAM runs the entire gamut of DDR400, CL2 to CL3. I don't believe there is anything wrong with the RAM whatsoever. I am reticent to spend $195 on 2GB RAM (you read that right!!!). hell, I could spend $195 and get 8 or 16GB of DDR3 1666MHz SDRAM (or even SO-DIMMs) at that price... sheesh
If anyone knows of a way to hook up a PC AT/ATX power supply to the Power Mac G5, I am all ears. The power supply is sealed in the bottom of the case... could be interesting getting to it.
thanks for any advice or help!
PS. I tried bad (PC2100) RAM, and only one chip, and I get the BAD/NO RAM single flash, so I think the auto detect is working OK.
Just before it fails, you can sometimes hear a faint POP, like it wants to start playing the chime, but fails just a moment before then.
PPS. Could this be a failing capacitor? Weird symptom?!
PPPS. the RAM inside to begin with looked very dicey old PC RAM anyways. Mix of plain and ECC. yuurch.