iMac G5 Screen Issue (Green pixels)

It's known problem in some G5 iMacs and first series of Intel iMacs.
Your LCD is faulty.If it was graphics chip, that lines should be visible on the screenshot too.
You can replace LCD or use external display

Edited: now i see these dots thanks to MacHamster's post. Seems to be graphic card's fault/overheating. Try do clean dust from your iMac first.

there are green dots visble on the screenshot

some one the left side around the rear wing of red car all the way towards that bush and on the right side
from the grill of the red car all the way up to spotlight , the dock is full with green dots too,but the safari window surprisingly is dot free , at least i could not see one or missed one
try changing the background picture maybe a solid color one several times and watch for dots or no dots
, so i guess its not your lcd screen , i guess its a graphic card issue , and as its a iMac g5
i would open it clean it and look for bulging capacitors , as the pre isight 1.6, 1.8 and 2.0 are known for bad caps which can effect the graphics card

MacHamster68 said:

there are green dots visble on the screenshot

some one the left side around the rear wing of red car all the way towards that bush and on the right side
from the grill of the red car all the way up to spotlight , the dock is full with green dots too,but the safari window surprisingly is dot free , at least i could not see one or missed one
try changing the background picture maybe a solid color one several times and watch for dots or no dots
, so i guess its not your lcd screen , i guess its a graphic card issue , and as its a iMac g5
i would open it clean it and look for bulging capacitors , as the pre isight 1.6, 1.8 and 2.0 are known for bad caps which can effect the graphics card

Click to expand...

I think MacHam got it right- most likely a graphics card issue. Open it to check for bulging caps, but also blow out all of the dust you can find, especially around the graphics card. I have seen too much dust cause these machines' graphics cards to act funny- sometimes cleaning them out can help.

If not, be prepared to bite the bullet and get a new machine. If you are handy with a solder, you can try to replace the bad caps if that is the problem, but at this point, you might be fixing one problem only to have something else go wrong in a month... or a week... and you'd be trying to keep alive a computer that is part of an end-of-the-road platform (PPC).

And rather than waiting for it to die, it might make sense to replace it while the machine still works and you can transfer your data safely to a new machine.

I'm going through the same thinking with my G5 iMac. I've kept it for far longer than I anticipated (in part a sentimental decision, as it was the machine that brought me back to Apple after fifteen years of wandering in the wilderness of Windows), and it has provided great service, happily running Leopard, and serving as the family computer in the den. Still, it's starting to have a few intermittent issues, and I'll probably replace it with a Mac Mini and a 3rd party monitor. Something to consider, if you can afford to replace it.

if it has bad caps and if you know someone or are yourself good with a soldering iron
the bad caps cost about £20 (sets are available sometimes on ebay or some apple repair shops), even giving a local radio repair guy a chance to solder them in might set you only back £50 and your iMac would be ready for work again

winterdude010 said:

Hello, thanks for the replies. I opened up the computer and all of the caps were fine. And there was very little dust in the machine. So I'm not quite sure what would be causing the issue now. The pixels appear as soon as I log in now and get progressively worse (I'd assume worse as the temp of the computer rises). The only odd thing I found were these green spots on the edge of the G5 area. I attached a picture, not sure what that would have come from but it doesn't seem to me that it's a normal occurrence.

Click to expand...

at least theses caps in the picture are fine , the green spots on the copper is oxidation , so i guess it was standing around in a humid environment for quiet a while or someone was washing it and water got inside ..which could explain something eventually water and electricity do not mix well on a logic board

but your graphics card is on its last legs i suppose , might last like that for a while or goes tomorrow , and as far as i know the graphic card is not replacable as its part of the logic board and a used refurbished logic board cost quiet a bit , dont even know if apple still has them new in stock, but certainly not cheap

but there is light at the end of the tunnel it might be worth to look ebay for same one with a broken screen or so ..if you dont have the money ready for a new Mac

but i would try to get a used mini and a monitor ...it might be cheaper too