Control Backlight regardless of logic board condition

3 replies [Last post]
Joined: Feb 13 2007
Posts: 1

I have a powerbook g4 titanium dvi. It has your standard backlight problem (screen on, viewable with flashlight) I have replaced various parts, including inverter and cables. The only thing remaining is the logic board. Things like switching back and forth from mirrored display mode, and plugging and unplugging an external display turns the backlight on for a second or less.

My question is this, is there any way to get the light on without replacing the logic board? Any hacks, hardware or software (command line?) would be appreciated.

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TheUltimateMacUser's picture
Joined: Jan 28 2004
Posts: 615

Well... i don't think software is going to do anything for you, this is most def. a hardware issue. Sounds like the inverter for the backlight is crapping out, or perhaps even the backlight itself. You may need to replace your inverter board.


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dankephoto's picture
Joined: Dec 20 2003
Posts: 1900
Have you . . .

reset the PRAM and the openfirmware? What happens when you boot from an install CD/DVD?

I'm not convinced this is a hardware issue.

dan k


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Joined: Oct 31 2007
Posts: 1
Microfuse on logic board could be the cluprit.

Hi I had this problem with my ibook and it turned out to be on the logicboard. I found info about a hack that involved replacing 12amp microfuse on the logicboard. I controls the power going to the backlight itself. The fuse was blown, so the backlight would not turn on. Like your powerbook the screen was dim but was visable with a external light source or an external monitor. I cannot remember where the info is for the fix, but when I find it I will post it. I may have been on this site.