History:
Liquid damaged no green light.
Burnt KBD backlight connector J4915 (removed and area cleaned) - no short to ground on pin 3/4.
D7010 missing (replaced) i've not idea why this was missing......
Now powering on with green light but no backlight. (Does boot up checked with microscope light there is an image present)
Q7700
pin 4 12.58v
pin 3 12.46v
0v on output
R7701, C7700, R7702 measuring fine. Replaced anyway as looked like they needed it.
R7700 0.2ohm
u7700
pin 11 12.46v (This is the problem i believe as it should pull LCDBKLT_EN_L low)
pin 17 (enable) 3.3v
pin 5&18 (power) 5v
R7731 & R7732 measure and look fine
c7701 replaced
tried replacing q7700 no change
with lcd connected.
PPVOUT_S0_LCDBKLT 0v
PP5VR3V3_SW_LCD 5v
SMC_LID 3.4v
DP_INT_HPD 3.3v
EDP_BKLT_PSR_EN 3.3v
R7750
R7751 both 0.2ohm
R7752
R7753 both 2.3k
pin 1 of LCD connector diode mode to ground: 1.1v
Does the same on two screens. (original screen quoted as working by customer, plus my known good screen - granted i haven't used it in a while). Relatively new to this so don't have any others to swap with at the mo.
Tried different LVDS cable for shits and giggles but no change.
i realise my issue is that LCDBKLT_EN_L (pin 3 of q7700) is not being pulled to ground and therefore not turning on. I've replaced the pre and post q7700 caps (c7700 & c7701) and the voltage divider to pin 3 as a caution.
u7700 has power pins 5&18 and enable pin 17 but is not pulling pin 11 (SD) to ground.
Forgive my naivity but could i try jumping pin 3 of q7700 to ground just to see if it goes further ?
I am rather lost now as to where to follow this - any hints please ?
Liquid damaged no green light.
Burnt KBD backlight connector J4915 (removed and area cleaned) - no short to ground on pin 3/4.
D7010 missing (replaced) i've not idea why this was missing......
Now powering on with green light but no backlight. (Does boot up checked with microscope light there is an image present)
Q7700
pin 4 12.58v
pin 3 12.46v
0v on output
R7701, C7700, R7702 measuring fine. Replaced anyway as looked like they needed it.
R7700 0.2ohm
u7700
pin 11 12.46v (This is the problem i believe as it should pull LCDBKLT_EN_L low)
pin 17 (enable) 3.3v
pin 5&18 (power) 5v
R7731 & R7732 measure and look fine
c7701 replaced
tried replacing q7700 no change
with lcd connected.
PPVOUT_S0_LCDBKLT 0v
PP5VR3V3_SW_LCD 5v
SMC_LID 3.4v
DP_INT_HPD 3.3v
EDP_BKLT_PSR_EN 3.3v
R7750
R7751 both 0.2ohm
R7752
R7753 both 2.3k
pin 1 of LCD connector diode mode to ground: 1.1v
Does the same on two screens. (original screen quoted as working by customer, plus my known good screen - granted i haven't used it in a while). Relatively new to this so don't have any others to swap with at the mo.
Tried different LVDS cable for shits and giggles but no change.
i realise my issue is that LCDBKLT_EN_L (pin 3 of q7700) is not being pulled to ground and therefore not turning on. I've replaced the pre and post q7700 caps (c7700 & c7701) and the voltage divider to pin 3 as a caution.
u7700 has power pins 5&18 and enable pin 17 but is not pulling pin 11 (SD) to ground.
Forgive my naivity but could i try jumping pin 3 of q7700 to ground just to see if it goes further ?
I am rather lost now as to where to follow this - any hints please ?