iMac G5 LED Diagnosis

Question

iMac G5 LED Diagnosis

Hello all.
I have one of the original G5 iMac series, a 1.8g 17". It has, up until Saturday, worked flawlessly and is long out of warranty (including the extended policy).

Here's the problem. It was working fine until it started locking up. After holding in the power button to force a shutdown I let it sit for a minute.
Power up-> no welcome chime-> black screen-> fans running normally.
Tried booting off the hardware diag CD-> locked up
Tried re-setting all parameters by re-starting and holding the power button until the loud beep....
Now into Open Firmware screen-> reset-nvram (ok) -> reset-all (ok) and it restarts.
Back to no chime, no display, fans running.
Took it apart.
Reset SMU-> no difference
LED1 is on solid.
LED2 comes on solid when power button pressed.

I'm leaning toward the logic board.
Thoughts?
Anyone have an idea what it costs? (I can replace it myself)
Would this just be throwing good money after bad? (Seems several people have replaced the logic board more than once).

iMac G5 1.8 17" Mac OS X (10.4.8)

Posted on Dec 11, 2006 4:49 AM

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Answer 1

MGW

Level 7

27,047 points

Dec 11, 2006 6:31 AM in response to Jonathan Baldwin4

It's not the logic board, LED 2 would not light up if it were. It's more likely to be the power supply unit, and despite the fact that you think you are out of the Rev A repair extension program, I would call anyway and check.

Let us know how you make out,

Miriam

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Answer 2

Dec 11, 2006 7:02 AM in response to MGW

Actually I have to disagree with you.
These documents:
http://docs.info.apple.com/article.html?artnum=86815
http://docs.info.apple.com/article.html?artnum=301283

State the following regarding the LEDs

LED 1 indicates that trickle voltage from the power supply has been detected. This LED will be ON when the computer is turned off and your power supply is working correctly.

LED 2 indicates that the main logic board has detected proper power from the power supply when the computer is turned on. This LED will be ON when the computer is turned on and the power supply is working correctly.

LED 3 indicates that the computer and the LCD display are communicating. This LED will be ON when the computer is turned on and video signal is being generated.

LED 4 lights only if the computer detects an over-temperature condition. This LED will be OFF when the computer is turned on and running at the correct temperature

In the case of my G5, LED 1 and LED 2 are on continuously with the power ON, (no chime, no display, fans running normally)

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Answer 3

MGW

Level 7

27,047 points

Dec 11, 2006 7:15 AM in response to Jonathan Baldwin4

Ahh, you never said the other LEDs weren't on, so I assumed they were (see the old adage about assuming....). In any case, the rest of my post stands, do contact Apple and find out if they will cover you.

Let me know please,

Miriam

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Answer 4

Dec 12, 2006 6:21 AM in response to MGW

Well Apple informed me that my computer was no longer under warranty or the iMac repair program (knew this) and that I'd have to pay for the repair of a replacement motherboard.

I said I'd me capable of replacing it myself and asked how much it costs.

"I don't know since we don't sell parts. You'll have to take it to a service center or to a store. If you take it to a store you have to make an appointment first on the Apple website."

I have to say, as the IT director for the company I work for... this was one of the least productive phone calls I've yet made to a computer company.

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Answer 5

Dec 12, 2006 1:05 PM in response to Jonathan Baldwin4

Unless you are a certified Apple technician they will not sell you the parts you need as the logic board is not considered a user replaceable part. That is not just true of Apple but of all computer manufacturers.

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