measure on the screen side what voltage you get on pins 38/39/40
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[SOLVED]820-2915-B with no backlight
- Thread starter DannyRinc
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same as connector side. The GMUX is acting up, removed resistor for PWM and ran pp3vs0 straight to the pad going to BKL_PWM and the backlight is good now. I'll check caps and voltage going into it to see what's up.
Yeah I wouldn't know where to begin with this... Not sure what enables that signal.
Yeah I wouldn't know where to begin with this... Not sure what enables that signal.
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U9600 sometimes causes no brightness on 3330/2915 boards and it is much easier to sell someone on permanent full brightness than it is to replace the mux. It's up to you at this point. If you feel your skills are up to it you can replace it, but if they aren't you killed a board that came to you with no backlight. Selling that to the customer is far more difficult than "we can only give you max brightness all the time."
The best would be if something but U9600 is causing the light to always be low, you replace it and it still doesn't work.. that would suck.
The best would be if something but U9600 is causing the light to always be low, you replace it and it still doesn't work.. that would suck.
I have also had 2 of these boards where PRAM did not bring back the BKL. I booted it in the OS without BKL and adjusted the brightness with the keyboard and it started working again. No idea what voodoo that was....try it. Also once I flashed the EFI ROM and that brought back the BKL.
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