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Fix a misbehaving backlight on PowerBook G3 machines System
I have noticed a weird problem with the PowerBook G3 Series that causes the backlight to go out right before the log-on screen appears. At that point, one can relight it temporarily by pressing either one of the Brightness buttons above the keyboard. However, whenever your PB G3 Series is put to sleep and reawakened, the backlight refuses to come on no matter what you do, short of a restart (followed by the temporary trick above).

Apple appears to have no clue what is going on. And I found no tips, fixes or solutions anywhere on the web for this problem, either.
There is a cure, however: start up in OS 9, and then start back up in OS X (remember to always use the shut down command here, not the restart command). I was so relieved when I discovered this fix, as the problem was driving me nuts!

[robg adds: This is the first I've heard of this problem, and I don't have a machine to test with ... can anyone verify the problem and/or the solution?]
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Fix a misbehaving backlight on PowerBook G3 machines | 16 comments | Create New Account
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Fix a misbehaving backlight on PowerBook G3 machines
Authored by: clong@mac.com on Jul 10, '03 10:18:47AM

I noticed the above problem when installing OS X on a couple of Wallstreet machines. I simply set them not to go to sleep when the power is plugged in, and hopefully our users won't have to put them to sleep on battery (they're probably only going to be used as PowerPoint players).

Chris



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Fix a misbehaving backlight on PowerBook G3 machines
Authored by: acroyear on Jul 10, '03 02:19:15PM

I have seen this happen on a TiBook 400 MHz. Two things that I found would fix the problem in my case (I realize that with the Wall Streets we could be talking about two completely different issues): one, hook up an external VGA monitor and the backlight should come on (in my case I was worried that the video card had died altogether until I'd done this), or two, boot into single user mode, and the video/backlight should kick in, and it should remember to stay on the next time you reboot.

HTH,
Acroyear



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Cause of Misbehaving Backlight
Authored by: DocMan on Jul 10, '03 07:08:07PM

The problem is with the Power Manager in Mac OS X. OS 9 doesn't have any problems with the Power Manager, but the X PM has a tendency to get corrupted. Symptoms of this corruption include the screen turning off and shortened battery life.



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Fix a misbehaving backlight on PowerBook G3 machines
Authored by: b-baggins on Jul 10, '03 10:32:24AM

I've verified this on two Wallstreets. The backlight fails on sleep in OS X under certain situations. The fix is to boot into OS 9, sleep the unit, wake it back up, then reboot in OS X.



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Fix a misbehaving backlight on PowerBook G3 machines
Authored by: michaelkvance on Jul 10, '03 11:42:59AM

Somethign similar happened with my 14" ibook 600: the machine wouldn't sleep when I would close the lid. (It would sleep from the Apple Menu.) The solution was to boot to OS 9, then back to OS X.

Very annoying.

m.

---
"Bought on stolen wine, oh a nod was the first step.
You knew very well, what was coming next."
-- The Smiths, I Don't Owe You Anything



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Fix a misbehaving backlight on PowerBook G3 machines
Authored by: tournesol on Jul 10, '03 12:16:11PM

I have experienced the exact same thing on my 233 mhz Wallstreet PowerBook. The problem occured when I tried to make a Mac OS X only machine, completely trashing OS 9. That didn't work. Got the display problem even while installing OS X.

The minute I installed OS 9 on a partition, the problem dissapeared. Seems as if OS X need something from the OS 9 install. Don't know what?!



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Fix a misbehaving backlight on PowerBook G3 machines
Authored by: cbseven on Jul 10, '03 03:47:44PM

I've seen this problem many times on more than one Pismo. The solution has always been a hard reset. I'll have to try the OS9 trick next time, but have had problems surface just by booting into 9 as well.



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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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Wrong number of colors
Authored by: anjo on Jul 11, '03 04:18:59PM

I had this too, and the fix (if memory serves) was to set the number of colors to 32K or above in OS 9 and then restart...



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Fix a misbehaving backlight on PowerBook G3 machines
Authored by: webster phreaky on Jul 12, '03 01:58:37AM

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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Comment submitted as a hint...
Authored by: robg on Jul 14, '03 09:48:09AM
Anonymous submitted the following comment as a new hint:
I have had the same problem, and accidentally found the fix for me. I was shuffling some RAM between machines and when I removed my top 256 RAM chip I no longer had the sleep no Backlight problem. It turned out that the chip was 133mhz and had worked flawlessly up til 10.1 and then the problem surfaced. Mine is a Wallstreet 1 292mhz.

After I fixed it I discussed it with an Apple Store genius and he made some reference to the fact that you can go 1 step faster with RAM, but 2 steps creates a problem. ie 66mhz,100mhz, 133mhz. I have no clue to the validity of his statement, but it fit the scenario. I haven't reinstalled any memory in my top slot-just 256 in the lower, and I haven't had the problem for almost 1 year.

I researched this problem fully almost a year ago, and found no reference to it. It seems to be a problem with a small number of people.


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Fix a misbehaving backlight on PowerBook G3 machines
Authored by: DKC on Aug 06, '03 11:12:17AM

I have the exact same problem in my PB Wallstreet g3 330Mhz w/o L2 cache which was upgrade to the sonnet g4 500Mhz 512ram and 30gig harddrive running OS X.2.

Could it possibly be a dead backup battery?



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Fix a misbehaving backlight on PowerBook G3 machines
Authored by: bromhead on Apr 04, '04 07:14:09PM

I would like to confirm that booting into OS9, putting the machine to sleep, and restarting fixed the problem for me. The problem was exactly as described by the original hint.

I didn't have OS9 installed on my machine however, so I just booted off an OS9 installer CD, and I could sleep from there.

My machine is one of the early, 233mhz, non USB powerbook G3, sleek "shark" design (not sure of the model name)

I also have upgraded the hard drive to a 20GB, and added a 133mhz 128mb memory chip, maybe one of these is common between the machines with the problem?

My battery also stopped working completely. From other comments I wonder if this is related.



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