possible video card issue

I am trying to help out my nephew by fixing his Imac G5 for him for a lot less than a repair shop. I can do just about anything with a pc, so I said I'd give it a try.

It's a 2005 17" Imac G5, from previous expirence and from what I've read on this forum, I believe it has a video card issue. I can't get the hardware diag to run or to start from osx disk, both options put up an apple and a running gear for a few seconds, then it freezes goes to a bunch of lines and puts up a dialog box that says "You need to restart your computer. Hold down the power button for several seconds or press the restart button.

Some how on 3 occasions, I got the desktop, but it only lasted about a minute and reverts back to the lines and dashes. When the lines are verticle their solid, when their hortizonal some are solid some are dashes.

I have reset the PRAM and the SMU and tried the internal start and reset to no avail.

I fully intend to include images, but I'm not sure I know how.

Thank you very much
Skip

I suspect you're correct in that the problem is related to the GPU. Each screen shot you posted also shows a kernel panic. (very similar to the infamous Windows BSOD)

I'm not exactly certain which video card is in your iMac G5 but MacTracker shows it to be a nVidia Geoforce FX 5200 Ultra AGP. You might check that to be sure - open it up and look. Anyway, you could try a replacement card if you can find one. Make sure the card is for the Mac. A PC video card will not work (different firmware).

Regards.

Thank you, is there a "how to" somewhere to replace the video card? PC's I know, this thing is completely different inside.

Here are several places you can try: ifixit

PowerbookMedic

Regards.

wobble413 said:

Thank you, is there a "how to" somewhere to replace the video card? PC's I know, this thing is completely different inside.

Click to expand...

Remember...there is no "video card" on an iMac G5 (as well as probably every other iMac). The "GPU" is part of the logic board (just like in most laptop computers), and therefore if the problem truly is the GPU...it is not as simple as removing the old one & popping in a new one like you would do with a PCI card in a "traditional" desktop computer.

- Nick

And quite often kernel panics relate to bad or the wrong type of memory. If you have upgraded the memory, take out the new modules and try to boot with only the original. Also quite possibly a hard drive failing.

wobble413 said:

Thank you, is there a "how to" somewhere to replace the video card? PC's I know, this thing is completely different inside.

Click to expand...

As Nick Pointed out (and the fact the iMac G5 has an integrated chipset) you will have to replace the logic board in order to replace the GPU. Like other iMac models (even the newer ones) the GPU is surface mounted to the board.

Sorry about the misinformation. Logic boards are quite expensive so you might want to think that one over a bit.

Regards.

Like "chscag" mentions...if the problem is with the GPU you more than likely need to replace the logic/motherboard...which is expensive.

And like "Harry" mentioned...kernel panics are very often caused by bad ram...so do what Harry mentioned...remove all ram (especially if it is new)...and then put the ram back in 1 stick at a time...and see if the problem reoccurs.

Good luck,

- Nick

Video card issue

Thank you guys for all the great info, I'll do some price checking and let my nephew know what he's looking at for repairs.

( Although, I really think he wants his father to buy him a new mac )

I just thought I'd try to save them some money.

Again -- Thank You Very Much