820-2915 missing lcd power enable

[jgraffis]

I've got a couple of these 820-2915 that have the same issue, missing LCD_PWR_EN at U9000.
what I've checked

R9094 10k pin1 0v
R9678 4.7k pin 1 .012v pin 2 2.6v
no short to ground.

looks like I'm just not getting voltage for LCD_PWR_EN coming form U9600. Any ideas?

 

[dukefawks]

External video?

 

[jgraffis]

Yes it does boot and runs on external.

 

[dukefawks]

LCD is not recognized. LCD and cable known good? C9010 have 3V? Backlight not coming on also?

 

[jgraffis]

c9010 3v is present, tested with known good screen and cable no backlight either. could maybe be the connector?

 

[dukefawks]

Check pin 6 and 7 on diode mode, once with screen once without.
SMC_LID high?

 

[jgraffis]

both pins at 1.051 in diode mode with screen plugged in and 1.053 without screen. SMC_LID 3.4V
SORRY pin6-7 diode mode .450-.473

 

[dukefawks]

1051 makes no sense. Those lines should measure a lot lower, 0.5 or 0.6 range.

 

[jgraffis]

sorry pin 6 was .450 pin 7 .473 didn't change when i unplugged the screen

 

[dukefawks]

Measure if pins 4 6 7 have continuity to the other side of an LCD cable.

 

[jgraffis]

no continuity on pin 4. 6 7 have continuity threw the cable. looks like its the connector?

 

[dukefawks]

The cable does flip left to right on the connectors, so beep out all pins on the other side.

 

[jgraffis]

ya i noticed that but still no continuity

 

[dukefawks]

Well, bad connector then, I bet someone tried to shove a 2012 cable in there.

 

[jgraffis]

lol probably. ill change it out and report back.

 

[jgraffis]

problem solved. thanks for running me threw the diag process. Now for the other ones.