G5 2.3Ghz: Can Logic Board have intermittent fault?

Hi,

My Mac = Power Macintosh G5 Dual Core (2.3) Specs (Late 2005, M9591LL/A, PowerMac11,2, A1177, 2023) @ EveryMac.com

Problem: Fails to boot - doesn't even give a startup chime. I can hear the HDD starting up, and the fans start ok and then go super speed after a minute... power light is obv on... but nothing else. No chimes, no errors, no video, no nothing.

I took it to a busy Mac shop who said to replace the memory. I replaced it with new Kingston memory and the problem still exists. I have tried the various methods of troubleshooting to no avail.

I have spent the last few weeks turning the thing on and off whilst busy working at my desk, in the hope it might start again so I could access some files. I positioned the RAM in the wrong slots and got the approriate chimes. I then positioned the RAM correctly and hey presto it booted up just fine! I copied my files and was dead chuffed. However, next time I shut it down it failed to boot again Repeating the above scenario no longer revives the beast.

It would be great if I could rule out the Logic Board based on the presumption that if the board had failed, the previous one-off successful boot wouldn't have happened. The capacitors all look great.

Run out of ideas now - the Mac shop seem completely uninterested and have suggested the logic board without actually testing it.

Unfortunately, trouble shooting an intermittent or suspected intermittent logic board means replacing it. It appears that it may indeed have failed although it could also be something else. (not very helpful)

Do you by chance have a spare video card you could try? Sometimes a video card failure can cause the symptoms you described.

Regards.

secret buzzer

Thank you very much, I appreciate your input and think I should try a video card, if I can get hold of one.