Power Mac G4 MDD FW800 power issues

[greystash]

Just throwing out another idea, have you tried replacing the GPU? When I tried flashing several GPUs I got this exact same behaviour with cards it didn't like (e.g. PC GPUs that need specific pins disabled, or PC GPUs that it was disgusted by). As soon as I removed and replaced them with a good GPU it booted as normal. Perhaps if your GPU has failed it's not happy about it, Otherwise maybe something could be wrong with the AGP port?

 

[Unknown_K]

I think Apple did weird things with AGP 4/8 sense pins for other functions so a G5 8x AGP card won't work in an older G4 AGP machine with a trace cut (plus the ADC connector is in different spots).

You can always use an old Apple PCI graphics card and see if that works getting around AGP altogether.

 

[BrunoBr]

Hello there !

Got a similar model, and I'm looking for help with similiar problem. But in my case, mine chimes and a few seconds latter it shuts down, no video and no other error. Is this a good thing it's is chiming ?

My bad ! Found out the problem and I've forgot to come back and update about it.

At first I was afraid it was a PSU problem as many have previously reported. I've ordered a new one and still had the same issues but with a difference this time. I was testing booting the machine opened and realized that before shutting down every time, there was a small fume coming out from bellow the CPU daughter card. That was enough for me. I found another Power Mac G4 MDD on sale with some missing parts but still turning on. The Logic board and CPU board they are working perfect. I've replaced the boards and now I've got this Mac working properly again. Cost me less than a new Logic Board + Daughter CPU card and got a spare PSU.


My logic board was faulty.