820-00138 no backlight on screen

[suzukigsxr1000r]

No liquid damage ,working with external monitor fine .
customer tried to replace broken screen but no backlight with any working screen , tested 4 of them with new lcd cables
F7700 is fine 0 ohm no short to the ground .
maybe the LVDS .

 

[2informaticos]

Do you get image without backlight?
Any componentet ripped off close to J8300?
Check ig all the caps and coils are there and OK.
Post voltages at pins 5 and 28-30, in the first seconds...

 

[suzukigsxr1000r]

When flashing the light on the lcd there is an image .
there nothing damage around at all .
the pin 5 is 3.3v
the pins 28-30 are 5v
but what noticed once turn it on in few seconds the heat sink is boing hot, not normal heat on normal Macbooks .
could be gpu ? Even I get external monitor ?

 

[2informaticos]

Post voltages for U7701 and D7701.
Check resistance to ground at both sides of D7701.

 

[suzukigsxr1000r]

I get 0v on the D7701

 

[JohnB8812]

What voltage do you get on backlight output?

 

[2informaticos]

"Post voltages for U7701"

 

[suzukigsxr1000r]

No Title

 

[smiba]

Please don't write your response in the picture description, its hard to read

 

[suzukigsxr1000r]

Since the components misplaced on the 820-00138 schematic
hard to find the numbers for resistors .
i have the 2.2ghz which bit different than 2.5ghz schematic.
on the backlight output I get 12.6v
I will post picture and make it

 

[suzukigsxr1000r]

No Title

 

[suzukigsxr1000r]

Have short to the gorund on this resistor but still give 5v and short to D7720,L7720
resistor has 0 ohm when I removed it then no short to the ground
but seems not the cause of the short , when I solder new one
short came back .
Maybe need to replace u7701 !

 

[2informaticos]

"hard to find the numbers for resistors"
So easy to check which pin of U7701 (or other chip/transistor) is connected with the resistors.
Should be good enough to identify them in schematic...

 

[suzukigsxr1000r]

Thank you a lot
fixed by replacing the U7701