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markus weiher
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iBook G4 Display totally Blank

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I have a iBook g4 with a "tiny" problem.

the screen doesn't show anything - the backlight is off and if i use a flashlight there is nothing on the screen.

can a faulty ISL 6225CA be responsible for that complete failure ?

Edited by: machead3 ( )

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mayer
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Hook up to an external monitor to test if the video chip GPU is gone or not.

i declared the boards death today at 08:33am - i sould get a 12" powerbook today and need a few parts from the ibook ;-)

markus weiher,

My condolences on the passing of your Book. I know it's hard to accept the finality. Sometimes you just have to pull the plug :-(

mayer,

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lemerise
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Even with a faulty GPU you should get screen lightning. As mayer suggess connect the iBook to an external monitor and check if you have video on the external. Are you sure your display is in good working condition. Was it tested on a working logic board ? Why do you suspect the ISL 6225CA ?

The whole lid was tested yesterday - it works without a problem. since i don't have a connector for this model, it's not that easy to plug an external monitor. when i put in a tiger setup dvd, it sounds like it's booting from it. the isl6225ca had made some funny things in the past (bad solderings @ pin1 & pin28) - that was afaik responsible for the inverter related issues - but can it be responsible for the missing picture too ??

markus weiher,

When pins 1 or 28 on the U28 chip are desoldered the symptoms are: iBook G4 doesn't boot (no chime) but fan runs full speed on a black screen. This chip failure doesn't have nothing to do with the screen lightning. Until you test the GPU by connecting to an external monitor it's hard to give you advice about your problem but if you get no video and no lightning on the internal known working display then the logic board is probably faulty.

lemerise,

thanks for the advise i'll try to get the connector is there anything on the logic board that controls both parts ?

markus weiher,

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RJ7
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I have an iBook G4 that works fine with an external but shows grey screen on the internal. As I rebuild

these machines part time, I tried a total of (4) other internal displays(inventory) with no joy. I read once

about a tiny fuse( marked "TH" ) that blows and it controls the signal to the screen (inverter?). I was

thinking this was the reason for the problem and easily correctable with a jumper. Anyone concur?

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Chris
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@ RJ7: could you fix this problem in the meantime? I am dealing with exactly the same situation...

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josephnbishara
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My iBook G4's display shows nothing, but external monitoring works fine. I connected the computer to an external monitor and I can work the computer.

I didn't crack the G4's display or anything like that - it just quit. When I use the external monitor and adjust the brightness and contrast from the G4's control panels, the *laptop's* blank display also brightens and darkens (though absolutely nothing is being displayed).

Can you diagnose the problem with that information? Thank you.

Please cut this question and past it as a New Question to get better help. Thanks

mayer,

Joseph, If your internal display is grey and you can modify the brightness then your inverter (lightning) system works OK. You probably have a problem with the LVDS (video) cable that could be unseated at one end or faulty. Other possibility would be a bad LCD panel. I would begin by testing the LVDS cable.

lemerise,

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