MacBook Pro 13 a1502 no backlight, external display works
Hello everyone need some help please trying to learn but i can see i need more smarter people help , i hope it make sense try to do as much reading as i can i got Macbook PRO 13 inch A1502 820-3476-a Backligh is not on, LCD 100% good because was tested on different macbook , i done a lot of video research regards it and reading in different forum ,even in ifixit a member @oldturkey03 gave me a really good tips too but i stuck on pin 17 of u7700 edp_bklt_prs_en is 0v so i tried to use schematics and board view to my knowledge but i stuck at this pin 17 i dont have 3v u7700
pin 5 5.15v, c7740 pin 1 5.15v, r7744 5.15v.
pin 18 5.15v, c7741 pin 1 5.15v, r7745 5.15v
pin 17 0v r7742 pin 2 0v , r7742 pin 1 edp_bklt_prs_en 0v, c7742 missing looks like it never been there.
R7733 0 ohms
pin 8 3.32v, c8340 pin 1 3.32v, pin 7 edp_bklt_prs_en 0v
r8309 0v but when i measure in 200k oms on multi-meter i am getting 100k looks good
r8331 is missing like it never been there
r1430 edp_bklt_en says 100k i am getting 34.5k this is doesnt look good to me
pin 1 on j8300 ppvout_s0_lcdbklt 0v
can someone please help me i would really appreciate it
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board number ?
@tech_ni A1502 820-3476-a ;)
easiest thing to do atm is replace u7700, after that check the enable voltage again
board number 820-3476-a is i mentioned that in a description , i done readings on u8330
pin 1 3v edp_bklt_en OK
pin 2 0v lcd_psr_en missing
pin 3 3v
pin 4 gnd
pin 5 0v lcd_psr_en missing
pin 6 3v edp_panel_pwr OK
pin 7 3v
pin 8 pp3v3 3v
so because i have on pin 7 3.3v u7700 pin 17 edp_bklt_prs_en start working too , but i dont have no backligh no display
por Tomas Maconka
and i dont understand what has change why at the beginning i didnt have on u7700 pin 17 any voltage and now i dont have
what i noticed , even though i tested screen and i know its 100% working when i try to put torch next to apple logo i still cannot see anything on screen like log in or sow
por Tomas Maconka