Q: Powermac g5 (single 1.6Ghz) won't boot

Hello, the RAM needs to be in opposing Pairs, one stick will not work.

The fans speeding up is normal safety feature when no OS is running.

Can you count the beeps or flashes?

1 beep = no RAM installed

2 beeps = incompatible RAM types

3 beeps = no good banks

4 beeps = no good boot images in the boot ROM (and/or bad sys config block)

5 beeps = processor is not usable

In addition to the beeps, on some computers the power LED will flash a corresponding number of times plus one. The LED will repeat the sequence after approximately a 5-second pause. The tones are only played once.

Note: In this case, a flash is considered to be 1/4 second or 250 ms or greater in length.

http://support.apple.com/kb/HT1547

Ah yes, they need to be matched Pairs also.

Could be the famous lead-free solder around the RAM slots, or that one of the sticks is defective.

If it can only "see" 256 MB of one, it'll only use 256MB of the second, for 512MB, since they have to match.

Very rarely, putting the RAM not in the inner pair, but the next pair of slots out will work.

I would personally try a fresh set of RAM in that. It should be relatively easy to get that RAM either through online, or from another PC or Mac. Like it was said before, you need to, in a G5, install RAM in matched pairs for it to even be recongnized.

Hi,

I have 2 flashes, so I assume I didn't match the pairs with my RAM. I have 2x1Go and 2x512MB. Am I suppose to put the two 512MB together and the two 1Go together ?

In this case, in witch slots am I suppose to put them ?

Thanks by advanve

Edit : I figured it out =)

Good work, but in case others wonder... it'd be like...

| | 512MB 1GB * 1GB 512MB | |

Good to know, that's what I did ! But you're right, I should have shared my results.