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Fix a misbehaving backlight on PowerBook G3 machines
Authored by: bservo on Jul 10, '03 04:16:54PM
Yes, this happened to my Wallstreet 300MHz when I installed OS X on a new 30GB IBM Travelstar hard drive after the original 8GB drive failed. One of the other symptoms I would see was the LCD would get really bright for a second before the backlight would go dim. There were a number of discussions about the problem on the Apple discussion boards a while back... maybe a year ago or so. There were some theories about hard drives, magnetic shielding, and the sleep sensor but I'm not sure if this was ever proven. It seemed to be reported more often for people who had upgraded thier hard drives (especially to the high capacity IBM Travelstars), but the problem wasn't necessarily limited to just these people.

I believe the same tip was suggested on the Apple discussion boards, too, since I've been running OS X on the PowerBook just fine for a long time now and I'm pretty sure I used it to get the backlight working properly again. Considering the OS 9 boot fix seems to work, if it does have to do with magnetic shielding, my theory is that OS 9 updates the PRAM with more tolerant threshold values for the LCD backlight / sleep sensor than OS X for the Wallstreets. Just a guess.

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Fix a misbehaving backlight on PowerBook G3 machines
Authored by: TvE on Jul 11, '03 05:10:37AM

I have seen similair problems on my PowerBook 333 MHz. Both before and after I have upgraded the HD to an IBM 30 GIG travelstar.


What I am observing is that:

1. The computer goes to sleep (either because I hav'nt done anything for a while OR because I close the lid).
2. I then try to wake it up.
3. The "I am sleeping" flashing LED stops blinking.
4. The display is NOT turned on.
5. I then get another grey hair and reboot (hard)


I have tried akmost everything (I thought)
I have NOT yet tried:

- to ssh into the mac to see IF it's actually alive (I think it is)
- connect an external monitor
- do the "boot to OS 9, go to sleep, boot to X" thing


What I have done is to replave it with a 867 MHz TiBook ,-)
BUT it's still a PITA problem that I'd like to find a cure for!



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Fix a misbehaving backlight on PowerBook G3 machines
Authored by: webster phreaky on Jul 12, '03 01:56:19AM

First, the magnetic problem with certain IBM/Hitachi and Toshiba 2.5-in HDD is well documented, see the story at Upgrade a PowerBook G3, Part 1 and 2 ( http://homepage.mac.com/techedgeezine/cart_mac_pb1.html ). The fix is there too.

I also have a backlight problem with OS X and a Wallstreet, but very different. Whenever I boot up in OS X 10.1..5, the backlight goes to full bright (this never happens when booting in OS 9.2.2). Never happened before installing OS X (separate partition, as you should).

I've tried Zapping the PRAM, nothing. This makes no sense. Anyone with an idea??



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Backlight on PB G3 occasionally "supernovas"
Authored by: csmith on Jul 12, '03 04:20:40PM

I, too, occasionally boot my WallStreet G3 to find the display is at full strength. This is with OS 9.0.4. I don't have OS X installed on that machine.

I'm trying to remember what precedes the bright screen. It happens sometimes after a post-crash reboot (but only in that context).

I have not had the problem with the blacked-out backlight, but OS X has not been on this machine, except one time (when I tried to install OS X 10.2 on an expansion bay drive, and got only a circle with a slash through it when I booted from that drive - I'd never seen that on my TiBook 667, which I've had since new in April 2002).



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