820-01958 no image

[Dildobagins]

Hi
I have a problem with logic board A2179.
I replaced the L8750 and the u8500. In addition, I replaced the burnt fuse of the F8400. I received a screen backlight but no picture. I additionally replaced u8595 but without positive result.
Can I do more ?

 

[2informaticos]

First of all, welcome to the forum!

Any history available?
What was the reason to replace all mentioned components?
Did you test with known good screen?
Do you get external video?

 

[Dildobagins]

No hisotri. MacBook suddenly stopped working.
I replaced all components because everything was burned. I had to rebuild the damaged pads.
No picture on the external screen.
Unfortunately I do not have another screen.

 

[2informaticos]

Check diode mode to ground at pins 1 & 3 of J8500.

 

[Dildobagins]

1- 0.39
2 - 0.69
3 - 0.67

 

[2informaticos]

Not sure about your readings; check schematic and boardview.
Pin 2 is ground!

You should get very similar readings at pins 1 & 3.

 

[Dildobagins]

My mistake
1- 0.39
2 - 0
3 - 0.35

 

[2informaticos]

U8595 is not image related.
Don't change things without reason.

Check DP_INT_HPD and 3V3_S0SW_LCD voltage (with LCD connected).

 

[Dildobagins]

DP_INT_HPD - 0v
3V3_S0SW_LCD - 3.3v