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need help, problem with BIOS 820-3330
- Thread starter Dozer
- Start date
i got the machine, working so far.
no backlight and blinking folder or sometimes a lock, no keyboard working (pram reset or only hold alt no reaction)
backlight fuse F9700 burned
no short from PPVOUT_SW_LCDBKLT to ground
in diode mode red on ground i got on PPVOUT_SW_LCDBKLT .571
so i replaced the U9701
after that still no backlight but the reading on PPVOUT_SW_LCDBKLT is already good .538
then I flashed in a known good working bios
after that i had backlight and the keyboard worked (for pram reset)
ASD starts but got a lot og line with errors white letters on black ground in the apple logo screen
so I cut out the Me region of the original bios and insert it on the same place from the good working bios
after that asd starting good
but there are no sensor tests, no extern video controller test
if i open the tests for intern controller there are all tests twice
only start video test is failing
in the system report i can "see" both intern and extern video chip
I think the problem here is something easy but need help to do it , i dont want mess it up.
thank you
no backlight and blinking folder or sometimes a lock, no keyboard working (pram reset or only hold alt no reaction)
backlight fuse F9700 burned
no short from PPVOUT_SW_LCDBKLT to ground
in diode mode red on ground i got on PPVOUT_SW_LCDBKLT .571
so i replaced the U9701
after that still no backlight but the reading on PPVOUT_SW_LCDBKLT is already good .538
then I flashed in a known good working bios
after that i had backlight and the keyboard worked (for pram reset)
ASD starts but got a lot og line with errors white letters on black ground in the apple logo screen
so I cut out the Me region of the original bios and insert it on the same place from the good working bios
after that asd starting good
but there are no sensor tests, no extern video controller test
if i open the tests for intern controller there are all tests twice
only start video test is failing
in the system report i can "see" both intern and extern video chip
I think the problem here is something easy but need help to do it , i dont want mess it up.
thank you
Last edited:
Duke you ar THE MAN!
it is working. All sensor test are there and internal and external tests
in the beginning was no backlight but keyboard everything working, after starting ASD the machine switchrd to the extern GPU and backlight was coming.
asd shows gmux switching error, I heated with 100 the GMUX a little and the error was history after that is backlight after restart from the beginning.
So I still replaced the GMUX with a good one (the old was blown up a little on the side)
So now everything is working fine.
Duke can you give the secret what did you do with the bios?
it is working. All sensor test are there and internal and external tests
in the beginning was no backlight but keyboard everything working, after starting ASD the machine switchrd to the extern GPU and backlight was coming.
asd shows gmux switching error, I heated with 100 the GMUX a little and the error was history after that is backlight after restart from the beginning.
So I still replaced the GMUX with a good one (the old was blown up a little on the side)
So now everything is working fine.
Duke can you give the secret what did you do with the bios?