Laptops :: IBook G4 Black Screen Except For When In Target Mode

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.