I have 2 820-4924 both have liquid damage, both ultrasonic cleaned, and both do turn on, and work, except there is no image or backlight,
here are the following readings:
U8339
pin 1: 0
pin 2: 0
pin 3: 0 (gets 3.3v for a few seconds after plug in charger)
pin 4: 0
pin 5: 0
pin 6: 0
pin 7: 0
pin 8:3.3v
U 7700
pin 1: 0
pin 2: 0
pin 3: 0
pin 4: 0
pin 5: 5v
pin 6: 5v
pin 7: 9
pin 8: 5
pin 9: 12.55
pin 10: 12.55
pin 11: 12.39v
pin 12: 0
pin 13: 0
pin 14: 2.3 (slowly drops to 0 then back up to 2.3)
pin 15: 0
pin 16: 5.13v
pin 17: 0
pin 18: 5.13v
F7700
Pin 1: 12.55v
Pin 2: 12.55v
Q7700
pin 1: 0
pin 2: 0
pin 3: 12.40v
pin 4: 12.55v
pin 5: 0
pin 6: 0
here are the following readings:
U8339
pin 1: 0
pin 2: 0
pin 3: 0 (gets 3.3v for a few seconds after plug in charger)
pin 4: 0
pin 5: 0
pin 6: 0
pin 7: 0
pin 8:3.3v
U 7700
pin 1: 0
pin 2: 0
pin 3: 0
pin 4: 0
pin 5: 5v
pin 6: 5v
pin 7: 9
pin 8: 5
pin 9: 12.55
pin 10: 12.55
pin 11: 12.39v
pin 12: 0
pin 13: 0
pin 14: 2.3 (slowly drops to 0 then back up to 2.3)
pin 15: 0
pin 16: 5.13v
pin 17: 0
pin 18: 5.13v
F7700
Pin 1: 12.55v
Pin 2: 12.55v
Q7700
pin 1: 0
pin 2: 0
pin 3: 12.40v
pin 4: 12.55v
pin 5: 0
pin 6: 0