[tavilach]

Yesterday, I decided to take my PowerBook into the common room. I closed the lid, brought it in, and then opened it. To my surprise, the screen was blank. I waited a few seconds, it still was blank, so I tried closing it, waiting, and reopening it...but it was still blank. I tried adjusting the contrast, but that doesn't work when the user isn't logged in (I have it set to request login after coming out of sleep mode), but I doubt that was the issue, as it seemed fully black (not just very very dark, without a backlight), and after a restart it was bright. I tried leaving it alone for a few minutes, but that didn't work. Finally, I just forced a shut down by holding down the power button, turned it back on, and that was it.

I thought it was a one time thing, but today I left my PowerBook to go eat, and when I came back, I couldn't get it out of the same black screen! I don't think I put it to sleep when I left, but I have it set to turn off the monitor after two minutes. The apple was still lit up, and when I put my ear to the computer, I heard running noise. I pressed volume keys, and I heard delayed noises (one second after I pressed a volume key, it made a volume noise). I couldn't get out of the black screen, though, after trying all the methods I used earlier, so I did a force shut down.

What is going on?

[tavilach]

Help! It keeps doing it!

[wilsonng]

I am also getting the same thing on my PB G4 12" 867 Mhz running 10.3.5

I tried to reset the PMU (Power Management Unit) and that worked for a while. The PMU is responsible for controlling the backlight, hard drive, sleep/wake modes, charging, trackpad and a few other things on the PB.



Here is the Apple KnowledgeBase article for resetting it.

http://docs.info.apple.com/article.h...um=14449#faq10

Over time, the settings in the Power Manager may become unusable, which can result in operational anomalies with the computer. Examples include not turning on, not waking from sleep, not charging the battery, or not seeing the AC Adapter, among others.

My laptop started doing this last week. It would go to sleep after 5 seconds from a wake up. It also wouldn't wake up.

The only way I could use my PB was to hook it up to a USB keyboard and mouse and an external monitor. But my PB's trackpad/keyboard wasn't responding. Only the USB keyboard and mouse worked. I launched Apple System Profiler and it said that there was no LCD display nor a keyboard and trackpad. It did sense the external display and the USB keyboard and trackpad.

I turned it in and am betting it will be covered under my AppleCare warranty. I hope the service guys can tell me something more than "we just replaced the logic board." I'd like to know what went wrong.

I'll be posting my report when I get my PB back (hopefully sooner than later)

[tavilach]

I don't have a problem with waking it from sleep, though. Sound still works (but the volume control has a strange one second delay before you hear the sound change), usually...

I think I know the issue, now, but I don't really understand it. I think that unplugging my keyboard might have something to do with it, as this seems to happen when I move my PowerBook somewhere else (it's only happened a few times, so I don't have many statistics). Unplugging the keyboard does wake it up from sleep, which relates to this. Also, unless I'm going nuts, my computer was in the process of waking up when I unplugged the keyboard, and I believe that after that I saw a blank screen...

I'm so confused. Help, world!

[wilsonng]

Hmmm.... Could it be that disconnecting the USB keyboard when the PB is asleep is shorting out the PB?

I used to remember that you could never disconnect an ADB keyboard and/or mouse while the Mac was on.

The computer lab I used to work in would always have to send the computers to Apple Service repair to fix them 'cuz the students would plug/unplug keyboard and mouse while it was still on...

I think the same thing happened to me. I do remember the PB was asleep when I unplugged the USB keyboard and then it would wake up. I would have to open up the lid to close it again....

Perhaps a defect that Apple is keeping quiet about???????

I remembered when the first generation TiBooks came out, they had problems with FireWire disappearing. I had to replace my logic board before discovering this. The 1st gen TiBooks would sometimes get an electrical backsurge that would fry the FireWire port thus necessitating a logic board replacement....