PowerBook G4 screen issues: uneven illumination; pink hues

Following up on our coverage of PowerBook G4 screen issues:

Uneven illumination As we mentioned yesterday, a number of users are describing issues of uneven screen illumination on PowerBook G4 models; we previously covered this issue in detail last November, but we've again started receiving reports. Reader Tom Grzelinski points us to a huge thread on Apple's Discussions forums:

"Please take a look at the Apple support discussion page for the full history of this issue. I too have had this problem 3 times and have just received my PB back from repair again. The problem typically takes 3-4 weeks to manifest."

The thread Tom references began last November and currently has over 500 responses, many as recent as today. (Note that Apple frequently deletes messages posted to the Discussions forums if they are deemed to be "inappropriate," so the actual number of reports posted to that thread may actually be higher.)

Pink hues, loss of brightness Yesterday we noted a few reports of PowerBook screens eventually developing a pink or red tint. We've since received a few more reports of this phenomenon. Reader D. Bruce Stevens writes:

"I have a 2.5 year old Titanium 800 MHz PowerBook and have been experiencing the pink screen situation for the past several months. When turning the computer on after powering down, or awakening from sleep, the screen starts out VERY pink and then gradually returns to normal over about a minute or two."

Note that this is somewhat consistent with Apple's Knowledge Base article discussing LCD "warm-up" -- although the display clearly shouldn't be pink, the color balance of most LCD displays will change somewhat as the display warms up, eventually reaching their "ideal" brightness and color balance.

MacFixIt reader Michael Witt also points out that the nature of LCD displays is that they eventually lose brightness, although not all screens are created equal:

"LCDs do lose brightness with use. How quickly, though, seems to differ by manufacturer: When I went out to buy a 17" LCD a while ago, I found, for instance, that Samsung's screen had a life expectancy of 20,000 hours, while Sharp's cited 50,000 hours (as per product information sheets). Since life expectancy is defined as the amount of time it takes for the screen to lose 50% of its original brightness, it would seem as if brightness in Samsung screens deteriorated about 2.5 times as fast as that in Sharp screens (assuming linearity). I suspect there are similar differences with other manufacturers. Given the rapid deterioration in brightness I have seen in my PB G4, my impression is that Apple may be using less durable components for its PB screens than it could."

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