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General discussion

iBook G4 black screen except for when in Target Mode

Sep 11, 2010 7:43AM PDT

Hi all. 1st time posting to this forum. My iBook G4's (1.2 Ghz) screen flashes grey/white for a brief second upon startup and then remains black. No ghosting at all... simply black screen though computer is running fine. Later, I decided to connect it to my desktop Mac and restart it in Target mode, and was surprised to see the standard blue screen with moving Firewire logo screensaver on my iBook's screen - no different than anytime before when I've booted in Target Mode.

I ran Diskwarrior on my iBook's HD from my Mac desktop and all was clean so not a HD problem. Btw, I used SuperDuper to copy my iBook's HD to Disk Image for backup.

With some semi-calculated guessing on my part, I had come to the conclusion - prior to seeing the Target Mode screensaver on my laptop's screen - that the LCD screen had gone bad. As a result of what may have been flawed reasoning on my part, I purchased a used replacement screen off eBay from a reputable seller. I will be getting that replacement screen in a few days (including working inverter board).

My question here is can the LCD screen actually be bad and need replacing IF the Target Mode screensaver works beautifully on it? And the follow-up question is if it's not a bad LCD screen, what might the more likely problem be? It doesn't seem like it would be a backlight problem because moving yellow/orange Firewire logo of the screensaver looks fine.

A couple of things probably worth noting here:

Earlier before first experiencing my black screen issue, the power cord was accidentally jerked by a passing foot when laptop was on floor. It was enough of a jerking motion to move the laptop's position on the carpet but I didn't think it was that bad at the time... now wondering if something may have been pulled loose inside.

As those familiar with the iBook will know, the power connector light is orange when computer is turned off and it's also orange when laptop is in Target Mode (with the screen seeming to work correctly). However, when not in Target Mode and turned on with screen black, the power connector light is green as it normally would be. Is it possible the screen is powered via Firewire port when in Target Mode and therefore bypassing some screen power situation via the power connector? Obviously the power connector must be working if i'm able to power up the iBook without the battery installed.

Now for the other bit of info which seems important to me and I'm embarrassed to even admit to here.. Just prior to experiencing my black screen problem, i was plugging my power connector into an electrical outlet near where I was going to use my iBook... In the past, I have always done that PRIOR to plugging the power cord into my iBook. Regrettably, that time I already had the power connector plugged into my iBook. While attempting to plug the connector into the electrical outlet, the prongs did not easily slide into the outlet and I heard some popping sounds which didn't seem too bad at the time. But it was immediately after that when my iBook's screen failed to start up.

Thanking anyone in advance who may be able to offer up some expertise regarding my situation. Also I should say that I am running OS 10.5.8 on my iBook. I realize the easiest thing for me to do to get this matter resolved would be to simply take the unit into a local service center for repair... but the value of the iBook at this point wouldn't be worth spending a large sum of money for repairs I likely can do on my on. Over the years, I've learned how to follow direction pretty well when it comes to replacing defective items inside my desktop computers, so I'm not terrified of doing same with my iBook.

Harvey

Discussion is locked

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Just for fits, grins and giggles,
Sep 11, 2010 9:16AM PDT

try booting from the OS X installation DVD, (or the iBook restoration CD) and see what you get.

The iBook G4 was notorious for a faulty piece of soldering on the logic board and this "could" be your problem.

Squeezing the case, top and bottom, just to the left of the trackpad would make the screen work again.

Try both,

P

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iBook G4 boots with black screen...
Sep 11, 2010 2:37PM PDT

Yes, I have tried doing both things which you suggested I try. Booting from both OS 10.5 intall disk and Diskwarrior install disk resulted in black screen preceded by the briefest glimpse of a blue screen. Keyboard caps lock lights up ok which leads me to believe laptop booted ok, though I am unable to view screen.

I had previously read about the iBook problem concerning video board and some bad solders. I went down to local Lowes store and purchased a C-clamp and tried it in several locations just left of the trackpad, but each time I powered up, the screen remained black.

Maybe I should have begun this thread with only one question. Is it possible for the LCD screen to actually be bad if the FireWire logo screensaver works perfectly when the iBook is started in Target Mode while connected to my desktop Mac?

Any other ideas?

Thanks again - Harvey

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Black screen problem with my iBook G4 has been resolved.
Sep 14, 2010 2:59AM PDT

I am happy to report that my problem has been solved. It was simply a matter of resetting my iBook's PRAM setting. I had previously read through all the posts I could find on what might be causing the screen failure I was experiencing, and various hardware solutions were offered up. Also I read several post about resetting the PMU, and had followed the steps to do that without success.

Last night I remembered years ago when I had to reset a desktop Mac's pram for some reason, and figured it would be worth a try. So I held down my option, control, p and r keys immediately after starting up my iBook, and I continued to hold down those keys until I heard the startup chime sound a second time. In just a couple of seconds, a gray screen came up with the Apple logo and I knew all would be ok. A short time later, my laptop was booted and running fine with my screen no longer black.

I have a replacement LCD screen on the way which I'll now have for a backup should mine actually go out sometime in the future. I don't have to purchase a replacement DC-in board and new ribbon cables or anything else - at least for now. Sometimes, the simplest things can be the solution we're looking for.

Harvey

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(NT) Good Job
Sep 14, 2010 4:37AM PDT
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Same Problem
Dec 16, 2010 11:52PM PST

I have the same problem. replaced the Inverter cable / cord. No luck. Reset PRAM but never get the second GONG. I figured the screen was bad until I started up in Target mode to get some pictures off. Screen looks normal in Target mode. Did you ever get an answer to whether the back light can be bad for normal work but still have the screen light up for target mode?? Any help greatly appreciated.
Ibook G4 1.2 GHZ 14 " screen
Os 10.5


Jack

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backlight is a backlight
Dec 17, 2010 12:46AM PST

it does not distinguish between regular and target mode.

If you didn't get the second bong, then you didn't reset the PRAM

What keys were you holding down?

P

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Same Problem
Dec 17, 2010 2:07AM PST

Option-control P - R all at once . I had tried the PMU reset earlier with no luck. But to be clear I was not 100% sure that I was using the correct method for my iBook.

Jack

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DUMB OL ME
Dec 17, 2010 2:25AM PST

I was indeed holding the Control key instead of the Command key. Thank you soo much. I seem to have a running iBook again.

Jack

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Hey, you did all the work
Dec 17, 2010 3:20AM PST

I just asked the question.

pleased you are back in business

P