01-20-2012, 09:48 AM

I have a g4 mac. So when I turn it on the front light lights up while your finger is on it, then goes off. The computer then stays on but there is no boot up chime and the screen stays black.

If you open the case the logic board light is red, the PSU fan turns on, the CPU fan turns on. So it seems to be getting power throughout.

I replaced the logic board with same results. Ive tried removing ram, changing hard drives, put a new PSU in it and tried 2 different video cards.

Reset pram tried to boot in safemode, Its basically all new components at this point and still does not seem to post.

This logic board is new from what I can tell. I would like to think its not its fault.

Is there anything else that I can try? Please help, ive put a lot of money into getting this fixed and now its just the principal of the matter as to why its not working I will try anything it doesnt make sense.

01-20-2012, 01:03 PM

285 views and not one person knows about apple hardware troubleshooting?

01-20-2012, 01:34 PM

Where did you get the logic board from? What model is this G4 Mac? Powermac if so which one? What CPU speed? Provide more info please as there are many different G4 macs. I am guessing it's a PowerMac G4 Tower but there are many with different boards, Ram speeds ETC.

There is no way over 200 forum members have viewed this in this short of a time. Must be guests who are not members here. Also few members know a lot about OLD mac hardware.

01-20-2012, 01:54 PM

Originally Posted by mrserv0n

Please help, ive put a lot of money into getting this fixed and now its just the principal of the matter as to why its not working I will try anything it doesnt make sense.

Depending on exactly which model G4 Mac you have...I sure hope that you haven't spend too much money getting it "fixed".

Some G4 Mac's are only worth about $25 bucks...some others are worth more...but almost none are worth more than $75-$100...since some Powermac G5 models can be purchased for $100-$150.

- Nick

01-20-2012, 03:44 PM

Sounds like an incorrect logic board. G4's are pretty fussy about the correct model parts being used. Generally logic boards are not replaceable by different models using a different system bus speeds etc.

And as Nick says anymore that $25 is money gone.

01-20-2012, 06:54 PM

Try to start it with the hard drive disconnected...you should of did this first on the old motherboard. You should get a flashing ? ... report back.