Macbook Pro 820-00840 have image no backlight

[mon2]

Re: Macbook Pro 820-00840 have image no backlight

This is a good reading.

Measure voltage of PPVIN_S0SW_LCDBKLTFET to ground @ F8400, pin # 1. This power rail should be the same value as PPBUS_G3H.

[Stevechurch]

Re: Macbook Pro 820-00840 have image no backlight

This is a good reading.

Measure voltage of PPVIN_S0SW_LCDBKLTFET to ground @ F8400, pin # 1. This power rail should be the same value as PPBUS_G3H.

pin 1 reads 12.63v

also F7000 pin 2 reads 12.6v

[mon2]

Re: Macbook Pro 820-00840 have image no backlight

Good. Continue to measure the voltage to ground for the enable mosfet @ Q8400. Measure with care for each of the pins on this component.

See attached for the x-ray view of how the pins are assigned. Look for a dimple in the package which denotes pin #1 then the pin count will be in the form of a letter 'U'.

Interested in the voltage to ground readings of the SOURCE, GATE and then DRAIN pins.

Post each measurement.

[Stevechurch]

Re: Macbook Pro 820-00840 have image no backlight

Good. Continue to measure the voltage to ground for the enable mosfet @ Q8400. Measure with care for each of the pins on this component.

See attached for the x-ray view of how the pins are assigned. Look for a dimple in the package which denotes pin #1 then the pin count will be in the form of a letter 'U'.

Interested in the voltage to ground readings of the SOURCE, GATE and then DRAIN pins.

Post each measurement.

Ok readings as follows
Pin 1 D = 30mV (raises from .2mv to 50mv then falls back)
Pin 2 D = 30mV as above
Pin 3 G = 12.6v
Pin 4 S = 12.6v
Pin 5 D = 30mV (raise and fall as above)
Pin 6 D = 30mV as above

[mon2]

Re: Macbook Pro 820-00840 have image no backlight

) check the following voltage rails on u8400:

U8400

VDDD PIN5 = 5V ?
VDDA PIN 18 = 5V ?

2) perform a pram reset 2-3 times.