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Yes as usual. I replaced also UP710 because there was around it some liquid damage. Also there was some corrosion on the Audio circuit, but not sure if that can affect the image and backlight.
UP710 measurements
pin 1 VDD 1.8v stable not losing voltage
pin 2 LCD_PWR_EN I get 1.8v and loses voltage when it's going to flash the logo
pin 3 PMU_SYS_ALIVE 1.2v stable not losing voltage
pin 4 EDP_PANEL_PWR_EN 1.8v and then losing voltage
pin 10 EDP_PANEL_DISCHARGE stable at 1.8v
pin 11...
I have this A2338 it was liquid damage in multiple places on the board. I removed the corrosion, resoldered all broken connections, and rewired some. The laptop is powered on but the backlight comes on for only 1sec and turns off, and still running and boots up on external. I replaced UP800...
I replaced the backlight chip and wired 1.8v from LID_OPEN_LEFT to LID_OPEN_RIGHT , and still the same. SMC_LID_LEFT/RIGHT are 1.8v also as they were even before
No problem, I will try. In the meantime, the backlight chip decided to stop working and shorted half of the board. I need to replace it and try again. No short when the backlight chip is removed. I will update asap
Because R4805 is removed and on pin 1 I have 0.85v, and on pin 2 I have connected R4804 pin 2 which has 1.8v. You said to remove R4805 and connect pins 1 & 2 of U4802
I just rechecked now and LID_OPEN_RIGHT stays at 0.85v even when pins 1 & 2 of U4802 are connected. All other signals are 1.8.
LID_OPEN_RIGHT goes to U6650, but no info about the chip on the schematics. Not sure if U6650 is on the board, under the shield which covers U7800.