Originally known as "The New iMac" the iMac G4 was created to replace the iMac G3 as Apple's all-in-one desktop computer. The G4 is easily recognizable by its swiveling monitor mounted above the hemispherical computer. Steve Jobs quoted it as being "a design that will last till the next decade."

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Red screen on iMac G4 20"

Hi everyone,

A friend of mine is offering me an iMac G4 20" with a problem in the screen and a disk problem. The iMac powers on normally, but the folder & blinking question mark appears over a red background even if you insert the system boot disks and press "c". He has replaced the hard disk with another one and nothing changed. Also there is the problem of the red screen, could it be solved with a PRAM reset? Maybe is some loosen conexion inside...The thing is if the two problems are related or they are completely separated issues

Here is a picture with the problem:


The question is, is it fixable? Should I buy it?


Answered! View the answer I have this problem too

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First, Red is not the normal background color for this system to boot-up with or without a drive with Mac OS present (blinking ?), it should be light grey.

You stated you tried the original systems disks (plain gray) or where they black Apple OS9 or OS-X logo'ed disks? It's possible you didn't have the correct system disks to boot this system. It's also possible the CD/DVD drive was not correctly reconnected to the logic bd.

In any case the HD is not working. Either he couldn't install the OS from the disks he had, or the drive is not installed correctly (or still bad). It's also possible the HD & CD/DVD logic on the main logic bd is fried.

I suspect you have some video issues here as well (that dam red screen) it could be just a loose wire. The fact your getting the question mark is a good sign as that means the system still has life.

The question I would ask your friend is who tried to replace the HD as I think they didn't know what they were doing. They could have blown the logic bd. and/or didn't put things back together again correctly.

This is a PowerPC (PPC) system (not Intel based) so most newer software won't run on it. Theres still a lot of stuff out there that does run on this system (used) so it might be a good system to start off with if you have a tech geek friend that can help you one on one.

In any case I wouldn't spend very much as it might not be repairable.

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Thanks for your answer, I know he didn't know what he was doing but anyway, if it runs to the blinking question mark I understand that the logic board is ok, isn't it? Apparently he is going to give it to me for free so I can't lose anything. The problem is that he is now at 800km away and until I receive it (he is going to send it) I canot try anything.

I have fixed more than one iMac G4 before but this is the first time I face this problem, that's why I asked.

Presumably the OS installed is Tiger OS X and he has used it's disks but I don't know it for sure.

I will first do a reset on PRAM and PMU, then change the HDD and see what happens, also I will try to see what happens if I plug an external monitor...

More ideas?

The worst it could happen is that I have to buy a logic board, isn't it?



Just because you have some life in the system (blinking ?) the logic bd still could have problems. - I Like free though ;-}


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