24" iMac 2.16 - failing video and/or logic board?

[StingMe]

Apple-Refurbished 24" iMac (2.16/1G/250/SD/AP/BT) - out of the warranty period, of course.

This iMac is unable to boot without kernel panics, freezes, and/or display glitches. I have tried booting from both the internal optical drive and an external optical drive (using the original installer disc (10.4.x) or a retail OSX (10.5.x) install disc) as well as an external HD (10.5.x; via Target Disc Mode) - all have failed at one point or another. These issues have been occurring with greater and greater frequency for several weeks and now the iMac appears to be completely unusable on its own.

The internal HD has been erased and attempts to reinstall the OS have failed, as noted above.

The normal startup chime is observed. Resetting the PRAM has no effect. Replacing the RAM has no effect. Replacing the keyboard/mouse has no effect. No additional peripherals are connected to the system.

When the LCD is powered up, it is peppered with what appear to be stuck pixels (lots of them - hundreds? thousands?). If a known-good external LCD is connected to the iMac via a new Apple miniDVI-DVI adapter, the external display also exhibits these "stuck" pixels and/or other video garbage.

The iMac may be started up in Target Disc mode and the HD accessed. The same "stuck" pixels are observed as the firewire icon moves about the display.

So, it appears that the issue is a failing video and/or logic board. Obviously, I do not know what was wrong with this machine originally, before it earned its "refurb" badge, but I can't help but wonder if it was suffering from a similar condition...

Are there any troubleshooting steps I haven't covered?

It seems I don't have too many options at this point - basically get it repaired by Apple (is there a flat service fee for iMacs as there is for MacBooks?) or sell it as-is/parted out (any ideas as to value?).

Any input will be greatly appreciated - thanks!

[Chupa Chupa]

Check to see what Console (in the Utilities folder) says. Often it will give a hint as to why you are getting the KPs. Also have you run the Hardware Test?

[StingMe]

No OS installed on the internal drive and most of the time the system freezes before I can really access anything anyway...

Forgot about holding down the D key at startup to access AHT on the OS installer disc, thanks.

[Chupa Chupa]

If everything comes up OK in Hardware Test you might try booting in safe mode (http://support.apple.com/kb/HT1455). It could be a bad extension loading in the pre-boot.

[incognegro]

Bad video when booted into target mode absolves the OS. It's very, very likely to be hardware.

You could get an estimate for a logic board - it probably has an integrated GPU, not a separate part.

I can't give you an exact price, but figure on about $600 for the board plus whatever labor the shop (or Apple store) wants to charge you.

[Biff Lugnut]

The video card on the 24 inchers is a separate card. It feels like the motherboard to me, but very well could be video...

[StingMe]

Ouch...logic board for about $700 installed; video card for about $300. I guess I'll give AHT a shot tonight and see if I can isolate the problematic hardware.

This same model iMac is currently available from Apple for $1200...maybe parting it out is a better solution

Anyone need parts?

Will post a followup if anyone's interested...

[M>B>]

Does this apply to your problem...

http://docs.info.apple.com/article.html?artnum=302181

I would call Apple, it might be another known problem. Try to get bumped up the line and talk to someone who really know what they are talking about. Most first liners just search their data base.

And, whoever you talk to get their name and phone number, so you won't have to go through all that in case you have to call again.

Have your serial number in hand as they might know about a bad batch of something.

Be polite, but persistent.

If it is something they screwed up they might repair or replace it outside of warranty, certainly worth a try.

The technical support number is...

1-800-275-2273

Please report back and repost your results!

[incognegro]

Not a G5 iMac, M>B>.

[StingMe]

Seven passes of AHT and "No trouble found."

Gonna try some other diagnostics.

I see lots of Apple Discussion threads dealing with this issue (it seems) - several users say they have had the graphics card replaced by Apple at no charge, even out of the warranty period.