820-3115 no image

[Gmorb]

I get a chime and a backlight but no image tested with a known good screen and no luck i just get a black screen.

voltages on pins 2,3,4 of j9000 are 3.2v

 

[2informaticos]

Do you have USB activity?
Check if L9080 is OK.
Next check resistance to ground on all LVDS_IG_A_DATA_ lines.
Be sure LCD connector has good connections and no corroded traces.

 

[Gmorb]

l9080 is ok
i do get usb activity
it works with external monitor
and im testing with a known good lcd

pin 8 = 3.86 mohm
pin 9 = 3.64 mohm
pin 11 = 3.83 mohm
pin 12 = 3.79 mohm
pin 14 = 3.85 mohm
pin 15 = 3.86 mohm

 

[2informaticos]

Data lines should be measured in diode mode, red probe to ground...

 

[Gmorb]

pin 8 = 526
pin 9 = 526
pin 11 = 530
pin 12 = 530
pin 14 = 532
pin 15 = 532

so i think i found the issue. theres a short on pad 1 of L9080. even after removing it the short is still there. by the looks of it i can see the only route that pad takes is to the gpu is this board fucked?

 

[2informaticos]

Resistance to ground look good.
Pad 1 of L9080 is shorted to ground?
Post resistance to ground on LVDS CLK lines too, before and after L9080.

 

[Gmorb]

On j9000

Pin 17 = 242
pin 16 = 0

not sure what you mean before it but if you mean before it reaches l9080 then its the same results. Without l9080 its 0 on both pins

 

[2informaticos]

Pin 16/J9000 is connected to ground...
Clock lines go to 17 & 18.

 

[Gmorb]

My bad 18 reads 0.010

 

[2informaticos]

That is more or less a short...
Is that reading whitout LCD connected?
If bad value remains on pad 1/L9080 after remove the coil, means bad PCH...

 

[Gmorb]

yup i thought as much. crap board.