G4 iMac iLamp video problem-- the aftermath.

[RAMd®d]

My buddy's G4 iMac ( http://forums.macresource.com/read/1/761...#msg-76158 ) went T/U and though it booted and "ran", there was no display.

He could not see the desktop in the display (I told you he checked) so took it to a trusted Mac hospital.

Diagnosis-- bad logic board.

Prognosis-- new board, and while he's in there, upgrade the "hidden" RAM, maybe add a 120/300G HD, depending on the limit of the controller.

He should have it back after two days.

[Refurbvirgin]

Ouch. What did that cost?

[WHiiP]

Sorry to hear about the needed surgery . . . I would like to hear more about the logic board failure if they can tell him what might have caused it, or what part actually failed.

Obviously a good time to be adding the other improvements . . .

Thanks for the f/u . . .

[incognegro]

i've replaced a few of these logic boards for the same symptom you described.

seems it's the video chip on the MLB that goes bad.

[particleman]

I have a G4 iMac 17" 1 GHz with video problems as well. The backlight comes on but no video. I can hook up a monitor to the external and use the computer. Could this be a problem with the logic board video chip? Or, could something have worked loose? The external video connector is soldered to the logic board while the lcd display uses a socket.

[incognegro]

could be the MLB, yes, particleman...

"when he's under water does he get wet, or does the water get him instead?"

[particleman]

incognegro Wrote:
-------------------------------------------------------
> could be the MLB, yes, particleman...
>
> "when he's under water does he get wet, or does
> the water get him instead?"

Thanks for the reply. It could indeed be a video fault on the MLB. It just seems odd that the external video puts out a useful signal while nothing goes to the flat panel. Are there two video circuits? I don't know. I don't even play an electrical engineer on TV.

Hopefully, when I get around to cracking it open and blowing the dust out, I will just find that the video connector has worked loose. Unfortunately, it is barely worth having it fixed.