6600 Views 4 Replies Latest reply: Jul 2, 2007 1:34 PM by Ralston Champagnie
Hi, Ralston. With the Powerbook running, the screen working normally, and window open displaying something in the center of the screen, insert a CD or DVD. If the screen goes dark, shine a bright light through the white Apple logo on the back of the display, artificially providing a backlight for the center of the screen. Can you see the window that was displayed there before the screen went dark? If so, your backlight isn't working but the rest of your Powerbook may be OK. The backlight is powered by the inverter, a small circuit board that sometimes goes bad. This is just a hunch, but it may be that when you insert a CD or DVD and the optical drive becomes active, it draws excessive power, "browning out" other components in the computer, and perhaps the inverter is taking the brunt of the hit. This may be because of a malfunction in the optical drive, or it may indicate that the Power Management Unit has a problem, or it may be that the inverter itself is close to failure and just can't take even a slight reduction in power.
You could start replacing parts yourself, but it might be expensive if you happen to guess wrong once or twice before finding the part that needs to be replaced, and you don't have ready and inexpensive access to known-good spare parts. In your shoes, I think I'd have a technician look the PB over.
I would suggest running the Hardware Test disc that came with the Powerbook, but if starting up from that disc leaves you with a dark screen, it would be very hard to learn anything that way.
Thanks for responding. Well it did it tonight without me inserting a cd or dvd. I turned on the laptop and after logining it went dark. I put a halogen light at the back as you said to do and I could see a pop-up window.
Does that mean its the back light for sure? I like to do my own repair as from past bad experience I do not trust computer technicians. Also Apple made these computer that a reasonable tech savvy individual can do repair themself.
Any link to instructions would be helpful. I use this computer alot and can not aford for it to be down for more than a day or two. I hope I can find the part on Ebay.
Powerbooks G4/1.04 & G3 Lombard-400 & PB3400 Mac OS X (10.4.9)
Hi, Ralston. A lack of backlighting is definitely the symptom, but its cause is still uncertain.
A take-apart guide for the 1GHz Tibook is here. Before you begin, make sure you have the required screwdrivers: they really are required. If you use the wrong type or size of driver you will strip the heads of the very soft screws used in the Tibook. Also get an anti-static wrist strap (available at Radio Shack or the like).
If after checking the inverter's connections you find them secure, replace the inverter board, reassemble the PB and test again.
It's quite unlikely that the backlight tube itself has failed, but if replacing the inverter makes no difference, you may have to entertain that possibility. Replacing the backlight entails either replacing the entire display assembly (Apple's approach) or dismantling the display assembly, which is glued together (for rigidity) and not intended to be taken apart. The latter can be done, but it's quite difficult and very labor-intensive, puts the whole display at risk, and may cause some permanent cosmetic damage to the display bezel. One man's methods are shown here. Apple technicians don't do this; paying a professional to do it would be more expensive for the customer than replacing the display.
I changed the inverter board with one I got off Ebay from I believe a trusted seller. After a straight 20 hrs no sleep test, the same darkness came over my beloved puppy(powerbook)
I guess this is a good excuse for a Macbook Pro...smile.
Changing the display is too involved process and would be expensive to take to a Mac-tech. In the mean time, when the display goes dark, I close it, let it sleep for a minute and reopen then all is well until it does that again. I appreciate your help
Powerbooks G4/1.04 & G3 Lombard-400 & PB3400 Mac OS X (10.4.10)