iMac G5 1.8 A1058 - AHT Errors = Logic Board?

[Teduk]

iMac G5 17" 1.8ghz 256MB RAM Model: A1058 (non-iSight), OSX 10.3.9

My iMac runs fine for about 5 mins from a cold start - but then freezes with the fans kicking into high speed. Any reboot at this point will not work unless the machine is left off for some time.
I have run the AHT (imac version 2.2.1) with varied results: -
Passes All Tests
Error Code - 2FAN/5/8: Hard Drive
Error Code - 2STH/1/3: Hard Drive
Error Code - 2MEM/2/4: DIMMO/J4000
and Numerous Script errors.

On reboot I get the 3 beeps and pulsing light on occasions.
I have checked the caps on the logic board and they all look intact (not burst).
The LED test buttons on the logic board performed as they should.

I took it to the Genius Bar and it crashed in front of the guy, he couldn't get the desktop back. He says it is most likely the logic board.

Does this sound right?

The more I read about the G5 the more worried I get about the many harware issues - is this model worth repairing?

Is there a cheaper way than through Apple (it will cost £400 here in the uk)?

Any help greatly appreciated

 

[edgew8]

There is a company on eBay that does mail in repairs of g5 logic boards relatively cheap.
I'm pretty sure they just install new capacitors as that was the major problem with those iMacs. If you still have problems after the re-capping then its most likely the power supply that was also plagued by bad capacitors.