pb g4 backlight control??

[arri]

hi

does anyone know something about how/where the backlight controlled on a pb g4 dvi?

the backlight wont come on anymore on an old pb i have. backlight itsself seem to be fine, also the inverterboard seems to work. i've tested this with two and a half other powerbooks i have around for parts..

you can see the screen actually just works..
and when switching resolutions the backlight will shortly come on and switch off again.my guess is i fried a part somewhere in the circuitry that controls the backlight...

any insights would be appreciated.

[icemanjc]

Did you try the control on the keyboard? The F2 key should turn it on and make it brighter, or if somehow you can see the Display Panel in System Prefs, you can rase the brightness there.

[arri]

hi iceman,

thanks alot for responding, but..

imagine me (big/bold guy) sitting here, with on my desk a fully dismanteled powerbook, and an open drawer at my left, holding 3 more powerbooks in parts..

it's actually a very good question! you point to the most basic and first possible solution... the one you would forget if you're trying to solve muc more complicated problems. so thanks again!

but in my case it's not that.
i've tried swapping screens, inverter-boards etc..but the problem seems to sit on the motherboard. probably some circuit that controls the inverter
so i'm afraid that that's just toasted.

i just hoped someone would know that replacing this or that capacitor could help.. but it's probably not worth hoping for..
capacitors are at least of a size you could deal with with bare hands, so i asume i instead fried at least 100 parts you can hardly see with a lookingglass..


but thanks again anyway!

[icemanjc]

yah, well, I didnt think very deeply, because, you did say it went on when switching resolutions, and I have heard that the problem for that is the brightness control, I've gone through about maybe 10 laptops (im a collector) and usually if the screen isn't working and I don't see any available ways of fixing it, i just give up on the platop and use it for parts.