Powerbook screen gone black

[JIII]

I have been using an external monitor for my 12in powerbook for the past few days. After installing new ram I turned the computer on and found that for some reason my LCD no longer lights up. if there is strong light I can still see the screen in the background, and the external monitor works perfectly, both as a mirror and as a second display. Apple System Profiler also reports nothing wrong, and when I use the dimming and brightening keys I can also see faintly the screen working. However, my screen remains black. I have tried zapping my pram a few times to no avail. Does anyone have any ideas about this?

-John

 

[jmgalvin]

Did you possibly do something to the screen strap when you installed the RAM?

I don't know about Powerbooks, but on my older iBook, that's one thing they point out in the "how to" book. You might check to see if it's firmly seated in the correct position - IF it's near your RAM slots on the machine.

Using OSX 10.3.9 on a G4

 

[JIII]

See but the thing is, the screen is functioning perfecly it just isn't drawing and power to the backlight. It's functionally preformming AS a screen. Also, the ram slot is tiny, and I could not see any cables near to it. I think there is just an internal issue with powerbooks and operating them with the screens closed, with an external monitor. Something has told the screen to stop drawing power [it usually doesn't have much] and it hasn't grabbed that power back, sadly. I hope I can get this figured out before school starts and I need the computer to take tests etc. on. I can't take a 19 inch CRT around with me now can I?

-John

 

[drlex]

Sounds like the backlight has failed; is it within warranty or covered under AppleCare?

soi la, soi carré

 

[jmgalvin]

Again, I'd check the strap. It supplies power to the screen as wellas info.

Using OSX 10.3.9 on a G4

 

[JIII]

Nah, sadly my computer is uncovered and I didn't get apple care. I will open it up again and check to see if anything is loose, but I have the feeling that it is not.

 

[ObviousTroll]

Wait - I've had this happen.

1. Hook back up to the external display, but leave your lid open and "detect displays" again.

2. It's possible that the only problem is that the backlight is turned off. try hitting the brightness-up function key.

 

[JIII]

I have tired using detect displays, and I mean it DOES detect the display, the system profiler lists the display and informs me that my graphics card has it's ram split 32 megs to each display. If you have the lighting right you can actually see the cursor etc. in the LCD. It seems like my backlight has been turned off for good... and I can't find a way to get it back on. If anyone knows of a way to reset the backlight perhaps, it would be awesome.

 

[ObviousTroll]

You might try booting off an install CD so that none of your software preferences/settings are loaded. That should at least tell you if you have a hardware or software problem.

 

[JIII]

So I just opened up the case again, and found a big ole nothing. I removed the ram and rebooted to see if there was an effect, which there was not. Then I booted up again with the ram in and it's working just fine, the ram is recognized. I also booted off the system software restore disk, and got nohing. The monitor itself is still working, just without a backlight, I saw no cables in sight when the ram cover was removed and I didn't go more than a centimeter in either direction when I installed it, so I see little or no chance of that happening. It's like something has been changed in the firmware that says "thou shalt have no light" and I can't figure out how to get the light back.

 

[ObviousTroll]

Sigh.

The only other possibility I can think of is that the LCD wires cracked, presumably in the hinge.

Time to give Apple a call, I'm afraid.

 

[DesperateHusband]

There were specific models of iBooks where there were warranty issues with the video logic board. Apple even extended the warranty for quite a while because of the recall problem.

see for details:

http://www.apple.com/support/ibook/faq/

The issues is, Apple won't repair the system without charge since the extended recall warranty expired in May of 2005.

Apple does have a flat rate laptop repair process, I believe it is around $299. Might be worth it to call them.

 

[twiSSt]

One of our I-books did something similar to this yesterday and i found it to be related to the battery and a bad surge protector/power strip that the laptop was plugged into. I found this by checking the battery that the lights were flashing, instead of being on or off.

try removing the battery and then with some canned air blow any dust/dirt from the contacts on the battery.

then plug in somehwere other than where you have been,and see what the results are.

I know this sounds off the mark, and probably appears to have nothing to do with your display, but like i said it worked in our case.

Twist

===========================================
Everything will be OK in the end.
If it's not OK, then it's not the end

 

[henrip]

JIII: did you solve this problem?

It's happening to me, but it's slightly more erratic -- things get better if plugged in to power, and sometimes changing the screen resolution seems to wake up the screen. But it's freaky because it's not consistent.

I think there may be an issue with the latch, which seems stuck.

--henrip

 

[JIII]

Oh, my problem is consistent alright, it hasn't ever changed. It sounds like you might have a wire loose henrip. I have tried all resolutions, left it plugged in, took the battery out, put it back, pulled my ram, re-inserted the ram, everything, no luck.

-JIII

 

[mcmark64]

JIII: Did you ever find a solution to this problem?

My PowerBook G4 12" VGA (867 MHz) is suffering from the same exact problem. In my case, however, I know that it is not a problem with the backlight itself, or the display cables, or the inverter board. It has something to do with the logic board itself. Here's the history: I had a flakey logic board that was going bad (no startup chime most of the time when I tried to boot), but occassionally my machine would boot up and work just fine. No problem with the display at all. So I bought a new logic board off of eBay from someone who said that his screen was black but that his PowerBook worked fine with an external display and he thought that the problem was with the display. When I put the logic board in my PowerBook I had the same results: black display (but when lit manually you can see that the video is working fine just like JIII's case) and the machine works fine with an external display (which I am using right now). I have seen a lot of articles posted in various forms describing this problem but in all cases people have responded with the same type of advice: bad cables, backlight burnt out, bad inverter board. (Except one case that mentioned that booting while holding down the 'R' key resets the display and it fixed his machine--this had no effect on my machine.)

Anyway, I guess if it is a bad logic board there may be nothing I can do about it. But does anyone know if I can just hard-wire the backlight to be on?

-- Mark Mc

 

[henrip]

In my case, the problem only occurs when on battery, and usually not right away. It's like the backlight gets tired after a certain point, though it most often happens when waking up from sleep.

I'll try pressing R when rebooting.