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  1. #1


    Member Since
    Jun 02, 2008
    Posts
    6
    Light sensor causes PowerBook G4 to sleep
    Like quite a few other Powerbook users, I have been suffering from the PB narcolepsy problem. Judging from experiences I read online, my PB might fall asleep more persistently as well as less often than many.

    After eliminating a faulty temperature sensor or battery to be the problem, resetting the power circuit, using memtestosx (I use non-Apple RAM) etc. I finally discovered, after a period of 6 months, at least one culprit:

    When I cover or otherwise dim the light sensor underneath the left speaker grill, my Powerbook goes to sleep. This is one cause I have not come across online (and there's a bunch of 'em). It explains, ofcourse, why the notebook would bail on me when handling the power cord (it's located on the left), or the entire machine. Why there did not seem to be any logic to when the screen would go black and the pilot light up, or when put on a desk and left for hours the notebook might keep working. Or not. I had to wait for a dark, rainy day and a flash of insight to properly diagnose the problem.

    Naturally, I would now like to know how to disable the light sensors using software/OSX (I don't care much about the automatically backlit keyboard). If that doesn't work or is incredibly involved (disabling a faulty temperature sensor sometimes is), there might be clues in the system.log and especially panic.log.

    Hopefully this thread might serve others suffering from a similar issue, many thanks to everyone helping out!

    Specifications:

    • Alu Powerbook G4 15" (FW800)
    • Tiger 10.4.11
    • 40 months old
    • non-apple RAM
    • recently replaced battery (old one had lost too much capacity as was to be expected after almost 3 years)


    The problem started about 6 months ago, several months after I got the new battery (re-installing the old one didn't change a thing).

    Logs

    A typical entry in system.log after the Powerbook has gone down:

    AppleUSBOHCI[0x2793000] Processing WDH before suspending
    Jun 2 16:57:34 Powerbook kernel[0]: IOUSBWorkLoop::closeGate - interrupt Thread being held off
    Jun 2 16:57:40 Powerbook kernel[0]: System Sleep
    Jun 2 16:57:40 Powerbook kernel[0]: IOBluetoothHCIController::restartShutdownWL this is a wake from sleep
    Jun 2 16:57:40 Powerbook kernel[0]: System Wake
    Jun 2 16:57:40 Powerbook kernel[0]: Wake event 0020
    Jun 2 16:57:41 Powerbook kernel[0]: UniNEnet::monitorLinkStatus - Link is up at 100 Mbps - Full Duplex
    Jun 2 16:57:42 Powerbook mDNSResponder: Repeated transitions for interface en0 (192.168.1.3); delaying packets by 5 seconds

    Sometimes I would be unable to wake my Powerbook at all, I recently discovered loads of kernel errors that have occurred in the past months. Today, for the first time, I also got an explicit one ("please restart your mac" message):

    Kernel version:
    Darwin Kernel Version 8.11.0: Wed Oct 10 18:26:00 PDT 2007; root:xnu-792.24.17~1/RELEASE_PPC
    *********

    Sat May 10 20:50:35 2008
    panic(cpu 0 caller 0x000A8C00): Uncorrectable machine check: pc = 000000000049E4D8, msr = 0000000000149030, dsisr = 40000000, dar = 000000002C259040
    AsyncSrc = 0000000000000000, CoreFIR = 0000000000000000
    L2FIR = 0000000000000000, BusFir = 0000000000000000

    Latest stack backtrace for cpu 0:
    Backtrace:
    0x000954F8 0x00095A10 0x00026898 0x000A8C00 0x000A7E90 0x000ABB80
    Proceeding back via exception chain:
    Exception state (sv=0x439EE280)
    PC=0x0049E4D8; MSR=0x00149030; DAR=0x2C259040; DSISR=0x40000000; LR=0x0049E42C; R1=0x21F33CB0; XCP=0x00000008 (0x200 - Machine check)
    Backtrace:
    0x002D4B80 0x004A0948 0x002D43D0 0x0003CA1C 0x000A9714
    Kernel loadable modules in backtrace (with dependencies):
    com.apple.driver.AppleUSBOHCI(2.5.5)@0x497000
    dependency: com.apple.iokit.IOUSBFamily(2.8.1)@0x463000
    dependency: com.apple.iokit.IOPCIFamily(1.7)@0x48d000
    Exception state (sv=0x00DA5500)
    PC=0x00000000; MSR=0x0000D030; DAR=0x00000000; DSISR=0x00000000; LR=0x00000000; R1=0x00000000; XCP=0x00000000 (Unknown)

    Kernel version:
    Darwin Kernel Version 8.11.0: Wed Oct 10 18:26:00 PDT 2007; root:xnu-792.24.17~1/RELEASE_PPC
    *********

    Sun May 18 22:15:57 2008
    panic(cpu 0 caller 0x000A8C00): Uncorrectable machine check: pc = 000000000049E4D8, msr = 0000000000149030, dsisr = 40000000, dar = 000000002C259040
    AsyncSrc = 0000000000000000, CoreFIR = 0000000000000000
    L2FIR = 0000000000000000, BusFir = 0000000000000000

    Latest stack backtrace for cpu 0:
    Backtrace:
    0x000954F8 0x00095A10 0x00026898 0x000A8C00 0x000A7E90 0x000ABB80
    Proceeding back via exception chain:
    Exception state (sv=0x439EE280)
    PC=0x0049E4D8; MSR=0x00149030; DAR=0x2C259040; DSISR=0x40000000; LR=0x0049E42C; R1=0x21F33CB0; XCP=0x00000008 (0x200 - Machine check)
    Backtrace:
    0x002D4B80 0x004A0948 0x002D43D0 0x0003CA1C 0x000A9714
    Kernel loadable modules in backtrace (with dependencies):
    com.apple.driver.AppleUSBOHCI(2.5.5)@0x497000
    dependency: com.apple.iokit.IOUSBFamily(2.8.1)@0x463000
    dependency: com.apple.iokit.IOPCIFamily(1.7)@0x48d000
    Exception state (sv=0x00DA5500)
    PC=0x00000000; MSR=0x0000D030; DAR=0x00000000; DSISR=0x00000000; LR=0x00000000; R1=0x00000000; XCP=0x00000000 (Unknown)

    Kernel version:
    Darwin Kernel Version 8.11.0: Wed Oct 10 18:26:00 PDT 2007; root:xnu-792.24.17~1/RELEASE_PPC
    *********

    Fri May 23 17:26:23 2008
    panic(cpu 0 caller 0x000A8C00): Uncorrectable machine check: pc = 000000000049E4D8, msr = 0000000000149030, dsisr = 40000000, dar = 000000002C259040
    AsyncSrc = 0000000000000000, CoreFIR = 0000000000000000
    L2FIR = 0000000000000000, BusFir = 0000000000000000

    Latest stack backtrace for cpu 0:
    Backtrace:
    0x000954F8 0x00095A10 0x00026898 0x000A8C00 0x000A7E90 0x000ABB80
    Proceeding back via exception chain:
    Exception state (sv=0x439EE280)
    PC=0x0049E4D8; MSR=0x00149030; DAR=0x2C259040; DSISR=0x40000000; LR=0x0049E42C; R1=0x21F33CB0; XCP=0x00000008 (0x200 - Machine check)
    Backtrace:
    0x002D4B80 0x004A0948 0x002D43D0 0x0003CA1C 0x000A9714
    Kernel loadable modules in backtrace (with dependencies):
    com.apple.driver.AppleUSBOHCI(2.5.5)@0x497000
    dependency: com.apple.iokit.IOUSBFamily(2.8.1)@0x463000
    dependency: com.apple.iokit.IOPCIFamily(1.7)@0x48d000
    Exception state (sv=0x00DA5500)
    PC=0x00000000; MSR=0x0000D030; DAR=0x00000000; DSISR=0x00000000; LR=0x00000000; R1=0x00000000; XCP=0x00000000 (Unknown)

    Kernel version:
    Darwin Kernel Version 8.11.0: Wed Oct 10 18:26:00 PDT 2007; root:xnu-792.24.17~1/RELEASE_PPC
    *********

    Wed May 28 16:16:43 2008
    panic(cpu 0 caller 0x000A8C00): Uncorrectable machine check: pc = 000000000049E4D8, msr = 0000000000149030, dsisr = 40000000, dar = 000000002C259040
    AsyncSrc = 0000000000000000, CoreFIR = 0000000000000000
    L2FIR = 0000000000000000, BusFir = 0000000000000000

    Latest stack backtrace for cpu 0:
    Backtrace:
    0x000954F8 0x00095A10 0x00026898 0x000A8C00 0x000A7E90 0x000ABB80
    Proceeding back via exception chain:
    Exception state (sv=0x439EE280)
    PC=0x0049E4D8; MSR=0x00149030; DAR=0x2C259040; DSISR=0x40000000; LR=0x0049E42C; R1=0x21F33CB0; XCP=0x00000008 (0x200 - Machine check)
    Backtrace:
    0x002D4B80 0x004A0948 0x002D43D0 0x0003CA1C 0x000A9714
    Kernel loadable modules in backtrace (with dependencies):
    com.apple.driver.AppleUSBOHCI(2.5.5)@0x497000
    dependency: com.apple.iokit.IOUSBFamily(2.8.1)@0x463000
    dependency: com.apple.iokit.IOPCIFamily(1.7)@0x48d000
    Exception state (sv=0x00DA5500)
    PC=0x00000000; MSR=0x0000D030; DAR=0x00000000; DSISR=0x00000000; LR=0x00000000; R1=0x00000000; XCP=0x00000000 (Unknown)

    Kernel version:
    Darwin Kernel Version 8.11.0: Wed Oct 10 18:26:00 PDT 2007; root:xnu-792.24.17~1/RELEASE_PPC
    *********

    Mon Jun 2 10:39:34 2008
    panic(cpu 0 caller 0x000A8C00): Uncorrectable machine check: pc = 000000000049E4D8, msr = 0000000000149030, dsisr = 42000000, dar = 0000000002353000
    AsyncSrc = 0000000000000000, CoreFIR = 0000000000000000
    L2FIR = 0000000000000000, BusFir = 00000000fff00000

    Latest stack backtrace for cpu 0:
    Backtrace:
    0x000954F8 0x00095A10 0x00026898 0x000A8C00 0x000A7E90 0x000ABB80
    Proceeding back via exception chain:
    Exception state (sv=0x38239000)
    PC=0x0049E4D8; MSR=0x00149030; DAR=0x02353000; DSISR=0x42000000; LR=0x0049E42C; R1=0x21F23CB0; XCP=0x00000008 (0x200 - Machine check)
    Backtrace:
    0x002D4B80 0x004A0948 0x002D43D0 0x0003CA1C 0x000A9714
    Kernel loadable modules in backtrace (with dependencies):
    com.apple.driver.AppleUSBOHCI(2.5.5)@0x497000
    dependency: com.apple.iokit.IOUSBFamily(2.8.1)@0x463000
    dependency: com.apple.iokit.IOPCIFamily(1.7)@0x48d000
    Exception state (sv=0x3841DA00)
    PC=0x00000000; MSR=0x0000D030; DAR=0x00000000; DSISR=0x00000000; LR=0x00000000; R1=0x00000000; XCP=0x00000000 (Unknown)

    Kernel version:
    Darwin Kernel Version 8.11.0: Wed Oct 10 18:26:00 PDT 2007; root:xnu-792.24.17~1/RELEASE_PPC
    *********

    Note that all of them mention a "Uncorrectable machine check", and all but the last one (that differed by manifeseting itself explicity on-screen) list "Exception state (sv=0x00DA5500)".

  2. #2


    Member Since
    Jun 02, 2008
    Posts
    6
    I should also mention that the option "Illuminate keyboard in low light conditions." in the Keyboard & Mouse options, as mentioned in the Apple help, has apparantly vanished.

  3. #3


    Member Since
    Jun 02, 2008
    Posts
    6
    I have physically removed both light sensors from the powerbook, and so far (half an hour) it has behaved perfectly! Hopefully I'll be able to confirm the success of the fix in a few days...

  4. #4


    Member Since
    Jun 02, 2008
    Posts
    6
    After a few days I can confirm that removing both light sensors cured my Powerbook from narcolepsy completely!

    It has shut down once when I woke it from a (normal) sleep session after which it failed to boot. I believe that is an unrelated issue having to do with the battery (last time it did that I immediately tested the battery in another PB and got a similar result). Leaving it for a few minutes seems to 'cure' the battery. Oh well, glad I can get on using what is still a great machine.

  5. #5


    Member Since
    Jun 11, 2008
    Posts
    1
    Unhappy D not see the light either
    Iam writting you from france. You have masterly described the same problems Ill been having with my G4 1.5Ghz.
    I was thinking in shortcircuiting the sensor`s wires in order to get a strait electrical flow instead of goig thru the cell sensor.have you ever heard of this possibility or any other that might work°
    Thank you in advance

  6. #6


    Member Since
    Aug 22, 2008
    Location
    Massachusetts
    Posts
    1
    Specs:
    Powerbook G4, 15" 1.67 GHz, 2GB
    The cure for the common narcolepsy
    Quote Originally Posted by bartvh View Post
    Like quite a few other Powerbook users, I have been suffering from the PB narcolepsy problem. Judging from experiences I read online, my PB might fall asleep more persistently as well as less often than many.

    After eliminating a faulty temperature sensor or battery to be the problem, resetting the power circuit, using memtestosx (I use non-Apple RAM) etc. I finally discovered, after a period of 6 months, at least one culprit:

    When I cover or otherwise dim the light sensor underneath the left speaker grill, my Powerbook goes to sleep. This is one cause I have not come across online (and there's a bunch of 'em). It explains, of course, why the notebook would bail on me when handling the power cord (it's located on the left), or the entire machine. Why there did not seem to be any logic to when the screen would go black and the pilot light up, or when put on a desk and left for hours the notebook might keep working. Or not. I had to wait for a dark, rainy day and a flash of insight to properly diagnose the problem.
    I have found the cure for this problem. After reading about this problem in a few placea and reading about the ambient light sensors (there are two), I did an inspection of the parts. The left hand ALS is rather small compared to the right hand side ALS. I came to the conclusion that it was the RIGHT side ALS which was having an issue. My thought being that with a logic board attached, it probably does all the logic. So with only the left hand ALS giving information, the computer was overreacting to low/no light.

    I bought a replacement right side ALS <a href="http://www.macrecycling.com/right-ambient-light-sensor-pb-aluminum-15-15167-p-100772.html">from this place</a> for $15 and it cured the problem.

    It was also mentioned in the thread that the options for controlling the automatic dimming had disappeared. This also cured that which leads credence to the theory that the logic is all in the right side ALS.

    I hope this helps. Your post got me to the conclusion I was seeking.

    -- Seth

  7. #7


    Member Since
    Oct 14, 2008
    Location
    Oslo, Norway
    Posts
    3
    Specs:
    PowerPC G4, 1.67 GHz, 1.5 GB RAM
    I have hardly ever felt more able to identify myself (or my mac's state...) to a problem description than this! Right to the last detail. I have for the last 6 months or so experienced the same problems: my PowerBook G4 from 2005 would suddenly go to sleep for no particular reason.
    After reading the postings here, I tried first to remove left sensor, but that made my computer go to sleep whenever i restarted it and in all other situations i could not see anything on the screen - it turned black but still running.

    When removing RIGHT sensor, it all worked perfectly well again: covering LEFT sensor does not make it go to sleep anymore. I don't have automatic dimming anymore, but I'll try to get myself a new RIGHT sensor and see if that solves that issue.

    THANKS for helping out to solve the problem!

  8. #8


    Member Since
    Sep 08, 2011
    Posts
    1
    Unhappy Ambient light sensor removal
    I have the same problem with my mac. How do I remove the light sensors?

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