(347) 552-2258 [email protected]

[SOLVED] 820-3437 and 820-2936 only half backlight LEDs working

Status
Not open for further replies.
F

Fizzl92

Member
Hello,
i am working on two waterdamaged machines. I could get both up and running but now both have every second Backlight LED not turned on, so that there are visible black shadows on the bottom of the screen. I tried different screens and they have the same issue. I have no idea where to look in a case like this. Both had waterdamage in the backlight area and i cleaned everything and replaced a lot of stuff including LP8550 on both. Is it ok to ask for help for both here in one post as they have the same issue or should i open another one for the second? Thanks for any advice!
 
F

Fizzl92

Member
In diode mode with the screen attached (820-2936):
Pin6 0,486V
Pin7 0,510V
Pin8 0,328V
Pin9 0,327V
Pin10 0V
Pin11 0,326V
The other one was already picked up (for now) as it is usable and the data was needed fast.
 
D

dukefawks

Administrator
The pins for measuring I asked applied to the 3437 board. Look at diagram and find the LED return lines yourself on the 2936 diagram.
 
F

Fizzl92

Member
Thank you with screen plugged in on the 2936:
Pin 24: OL I guess thats the problem.
Pin 25: 0,607V
Pin 26: 0,609V
Pin 27: 0,604V
Pin 28: 0,606V
Pin 29: 0,607V

I followed Pin 24 and... there was not even a resistor on the board...I put one in and the measurement goes up to 0,601V and it works perfektly now (except of a firmware password).... I totally missed that... Sorry for the dumb question i just never heard of LED return lines before this one so at least i learned a lot from you. Thank you very much.
 
Status
Not open for further replies.
Top