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 Post subject: intermittent failure of backlight
PostPosted: Fri Sep 12, 2008 8:46 pm 
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System is MBP17 w/ 2.16 and 2GB (after market RAM). While under warrantee I went through several displays. Original was warped, dead pixels, crushed in fall, no i-Sight. Now the backlight will not come on after sleep at random intervals. The failure will happen under battery or wall power. It may occur after display or machine sleeps. Sometimes all that I need to do is close the LCD and reopen and the backlight works. Sometimes it stays off for days. The external monitor works with no issues at all times.

On the surface is seems to me that I may have a loose cable. I have not checked as I was unsure how to get into the machine and while I have no fear of the device I do fear the "wrath of wife" if I accidentally damaged something (thanks to your demo i will be checking this out in a day or two).

Has anyone else experienced this? All I am finding is all or nothing but not intermittent.

Thanks

Jaysen


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 Post subject: Re: intermittent failure of backlight
PostPosted: Sat Sep 13, 2008 8:46 pm 
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Joined: Fri Sep 12, 2008 8:37 pm
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Two things I forgot to mention:
1) The Apple logo does not light up with the backlight fails.
2) I Have had a mobo replace done between the last 2 display swaps. That was a firewire issue. The display was replaced after that.

If anyone is counting that is 4 warrantee repairs. My previous Dell system was 8 in 6 months so Apple is still ahead in my book.

An update: I opened the case, checked the connections to the mobo (on of which seemed not fully seated) and then closed the case back up. At this point the backlight has failed completely, but given the history of this problem I am not declaring it worse yet.


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 Post subject: Re: intermittent failure of backlight
PostPosted: Mon Sep 15, 2008 9:34 am 
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It sounds like an inverter board problem, but there is the possibility it could be the LCD, inverter cable, or even the logic board.


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 Post subject: Re: intermittent failure of backlight
PostPosted: Mon Sep 15, 2008 11:27 am 
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After 24+ hours I can tell you that there is no change in behavior.

Can you recommend any additional trouble shooting steps that I can do prior to ordering parts?

Thanks.


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 Post subject: Re: intermittent failure of backlight
PostPosted: Wed Sep 17, 2008 2:39 pm 
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It really depends how the problem started. If it used to be an intermittent issue then its more likely to be the cable. If it went off all the sudden, its more often the inverter board. If there was a liquid spill, it is probably the logic board.


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 Post subject: Re: intermittent failure of backlight
PostPosted: Wed Sep 17, 2008 6:44 pm 
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The start of the problem was a long trip. Used the system for about 15 minutes and closed the lid, put it in its back (tom bihn brain cell + empire builder, put the bag on the top of the luggage in the trunk, then drove for 6 hours in 90+ heat. At the destination I opened the laptop did some work, got called away for 20 minutes and the system went to sleep on its own. When I came back and woke the system I was greeted to a blank screen. Thinking I had a incomplete recovery I closed the lid, opened it and the screen was back.

OVer the next few days This happened off and on. Sometimes the screen was blank when I opened the lid, sometimes on start up. These days it is so random that I just close the lid and reopen, if still bad power off, repeat until it comes back. Typically this is less then 3 times. If I get to 4 times I just close the lid and wake from the external keyboard forcing everything to the external monitor (I run dual headed 90% of the time).

I am thinking I should probably order a cable and inverter. From other posts it sounds as if I could return whatever one I do not need. In searching the parts list I can locate the inverter but not the cable. What part number should I order?


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 Post subject: Re: intermittent failure of backlight
PostPosted: Thu Sep 18, 2008 8:58 am 
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The cable comes with the front bezel.


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 Post subject: Re: intermittent failure of backlight
PostPosted: Wed Sep 24, 2008 3:33 pm 
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Over the weekend I upgraded to leopard due to software requirements. Since then I have not experienced the issue. this makes no sense to me at all since I had dona wipe and install using the supplied 10.4 recently.

Has anyone else reported this type of situation (upgrade fixes what appears to be a hardware problem) before?


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 Post subject: Re: intermittent failure of backlight
PostPosted: Thu Sep 25, 2008 8:36 am 
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I haven't heard of a software problem that could cause issues like that before. Glad you got it fixed though.


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 Post subject: Re: intermittent failure of backlight
PostPosted: Thu Sep 25, 2008 9:54 am 
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I am not sure it is fixed it just hasn't displayed the symptom. :)

Quick thought though, would upgrading to the LED display eliminate the need for the inverter? I normally don't do this level of hacking with my hardware, but the extra resolution is appealing.


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 Post subject: Re: intermittent failure of backlight
PostPosted: Tue Sep 30, 2008 11:12 am 
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A lot more hardware would need to be replaced to switch to an LED screen. I don't believe it is possible, but we haven't had one of the new LED models in the shop yet to see.


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 Post subject: Re: intermittent failure of backlight
PostPosted: Wed Oct 01, 2008 8:29 am 
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At this point it seems that something in 10.4 did not like the system. the update to 10.5 seems to have eliminated the symptoms. This seems odd to me, but so far so good.

Thanks for the help.


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 Post subject: Re: intermittent failure of backlight
PostPosted: Wed Oct 29, 2008 11:32 am 
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Update....

Everything was beautiful until this weeks Air Port update. Suddenly the symptoms return worse then ever. After a few days of futzing around I booted from my OSX10.5 dvd and the previously dysfunctional LCD started working on the first boot at the point of OS level screen detection. I did a hard power reset (power button for 5 sec) and forced the dvd eject to boot off the internal drive. No LCD.

Being the suspicious person that I am I repeated the boot from DVD and presto functional screen One thing that I noticed was a distinct change in the time from power up to the "boing" during the different bots that I did not recall existing BEFORE the Airport update. This time I did a proper shutdown from the DVD boot. I noticed a screen that looked like the gray boot up (with the apple logo) but with a folder or rectangle just prior to power off. A reboot to the internal disk with an extremely long and visible firmware load time and the screen was fully functional.

Since that boot
• firmware loads are back to normal (sub 5 seconds to the OS boot and the apple logo is visible).
• LCD is fully functional

All this to ask the following question: Are there any known conflicts between the ATI and airport cards in the 2.16Ghz revisions of the MBP-17?


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 Post subject: Re: intermittent failure of backlight
PostPosted: Thu Oct 30, 2008 9:05 am 
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I've heard of problems earlier this year with an update and people reinstalled an old update. Here is the thread. I've heard a couple of issues with the new update from customers, but can't find anything online in a quick search.

http://discussions.apple.com/thread.jsp ... 4&tstart=0


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