iMac G5 Logic Board Issue?

I'm no Apple technician, but fragmented lines across the screen does indicate a logic board/GPU failure. You could try your luck with Apple customer service, but given that it's an aging computer (these days, 5 years to Apple appears to represent an eternity), prepare to commit to a logic board/GPU replacement. If there's no guarantee attached to the rebuild, you should probably avoid it.

As an alternative, you may wish to look into how much you could get for the G5 in its current condition on eBay or Craigslist, and put the money towards a new unit. Even a couple hundred bucks in addition to the $500 you'd have to spend on the repair could get you well on your way to a very solid newer unit.

feel sorry for you , but it was something to expect from a early g5 iMac
,logic boards produced between 2003 and late 2004 which had been fitted up to early 2005 in iMac`s g5 had bad capacitors and its only a matter of time the bad caps start leaking some sooner some later, but bulging is visible very soon in their life , and makes them now beyond economical repair if you cant solder new caps in by yourself
apple did offer a repair extended warranty in 2006 or so but that past now so ... bad luck they did not make it really public back then

thats why i bought the eMac g4 1.42 ok i bought it mainly because of the crt,but also because of they had no bad cap problem , early iMac g5 which i avoid to even look at because of the bad cap risk , i only look at the iMac g5 1.9 - 2.1 late 2005 onwards as they had been build without that bad cap issue, but are still to expensive for me as i have set a limit of max £250 for a used computer which i will never break ( i live n the uk so we do not have the opportunity to get mac`s for peanuts like the nice people in the states which get new ones from apple for the price we pay for a 1-2 year old used one and i`m not willing to subsidize us buyers so i do not buy new ones )

Hi, I have early iMac G5 September 2004. Logic board died due to bad capacitors within 6 months of buying it. Apple put new logic board. This was in 2005. (Apparently you can see bulging capacitors or leaked capacitors if you open the back).

Since then only other problem I have had is power supply replacement.

Although my computer works well, the age is catching up. Newer programmes do not work with power PC. Large jpegs take time to open. This means I am looking into new imacs.

Several issues with the current lot. I am waiting for revision of current line so that the product is more reliable.

effected by the issue of bad caps had been the iMac g5 1.6 and 1.8 and i think but not hundred percent sure the 2.0 , unaffected had been the later 1.9 and 2.1 iMac g5`s
so if yours would be one of them is hard to tell , as its not a question when you bought it , its a question when the logic board inside had been made and even then there had been some effected and others not
the easiest way would have been if you would have opend it after couple weeks after you bought it the bulging caps could easy be spotted other indicator would have been on the top slot where the hot air comes out some fine layer black dust in the slot
also some suffered from a screen problem too
just look up iMac g5 and screen , psu, bad cap ...problems and hell brakes lose in google and different answers to the when it began and when it exactly ended

but there is a way if its the caps , there are sites where you can find listed the bad caps (the ones that need replacing) so the cheapest way of getting them replaced is (if you cant solder yourself as it can be quiet tricky )
get the caps , take out the logicboard , which is not so difficult to do and look around for a small tv repairshop and get them soldered in they usually dont charge as much as a apple repair centre

a mate from me got it done to his eMac 1.25 model which suffered the same bad cap issue
for less then € 50 including the caps in some sort of radio repair shop