A few years ago we had a few 1.6GHz 17-inch imac G5 systems at my high school, we took 'em to Vegas and had both of their boards replaced and the systems generally cleaned up. In a few weeks/months, one of them was back to generally misbehaving. A few months later I'd been told by the teacher to expect that the systems would be heading toward the proverbial "dumpster" of the school district. I haven't spoken with her very much since then.
Due to the nature of that program (Photoshop CS3/CS4 these days) and the way G5s are, the only PowerPC systems in active use are a powermac g3 that has a film scanner hooked to it, and the G5 at her desk.
We spent maybe $3700 if not more on that last-gen dualcore 2.3GHz G5, popped 6 or 7 gigs of ram into it, upgraded the graphics card to the nVidia 7800, and generally tricked it out. And a few months later, grabbed a 1.83GHz Core2 mac mini (GMA950) and were unsurprised but saddened to find out that it did most if not all of her desktop tasks better and faster than that G5 did. "But it's the server," I insisted.
And so it was.
My long-winded point is that iMac G5s have been for a long time, and continue to be odd creatures. Even if for whatever reason I got one that worked fine for free, I don't know how long I'd trust it to continue working fine.
Also, since you listed every single part in the machine except the motherboard, I'm going to go with Mars478 and Quad650 and go "It's probably time to either fix-again or replace-again that board."
Addition: Or the processor, I suppose the processors aren't socketed in any way though, so, "the board" would be the part you may want to look at replacing.
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Due to the nature of that program (Photoshop CS3/CS4 these days) and the way G5s are, the only PowerPC systems in active use are a powermac g3 that has a film scanner hooked to it, and the G5 at her desk.
We spent maybe $3700 if not more on that last-gen dualcore 2.3GHz G5, popped 6 or 7 gigs of ram into it, upgraded the graphics card to the nVidia 7800, and generally tricked it out. And a few months later, grabbed a 1.83GHz Core2 mac mini (GMA950) and were unsurprised but saddened to find out that it did most if not all of her desktop tasks better and faster than that G5 did. "But it's the server," I insisted.
And so it was.
My long-winded point is that iMac G5s have been for a long time, and continue to be odd creatures. Even if for whatever reason I got one that worked fine for free, I don't know how long I'd trust it to continue working fine.
Also, since you listed every single part in the machine except the motherboard, I'm going to go with Mars478 and Quad650 and go "It's probably time to either fix-again or replace-again that board."
Addition: Or the processor, I suppose the processors aren't socketed in any way though, so, "the board" would be the part you may want to look at replacing.
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[Insert Cool Signature here!]