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I

iFix

Member
Hi.

I have this laptop which the client said the screen was showing purple lines on screen when on 45' angle but since he got it here the laptop didn't show picture at all only backlight. I measured j8500 and on pin 6 with diode mode the value seems high 1.600 so i followed the line to R0557 which should be 100k but when measured on the board it's 47k. I removed it and it's 100k when not soldered and the value on board stays the same. R4830 it's measuring fine. Any ideas please?

Thanks :D
 
2informaticos

2informaticos

Administrator
Staff member
Check if Apple can still change the screen for free.

Onboard mesurements for high value resistors, almost never show the nominal value; is normal, depending by other components.
 
I

iFix

Member
Ok thanks looks like an lcd issue. If i replace the full flex should be fine i think. I'll advise the client :)

Good day :D
 
I

iFix

Member
Hey guys. Not an lcd issue i got a new one and power on no image, would appreciate some assistance :)
 
I

iFix

Member
I'm measuring now and on the backlight circuit on Q8400 i have voltage on PPVIN_S0SW_LCDBKLT_R and on contacts 1,2,5,6 nothing. I'll keep measuring the components and update... There no Image if anyone wanna ask :)
 
2informaticos

2informaticos

Administrator
Staff member
If no image present, no reason to search for backlight.
Backlight appears after image get stable, to avoid any artifacts on the screen.

Check first if you get external video, or at least USB activity.
 
2informaticos

2informaticos

Administrator
Staff member
"Brand new" chinese?
Check again with original assembly.
If backlight comes on, there must be a problem with internal eDP data lines; if no image.
 
2informaticos

2informaticos

Administrator
Staff member
If you don't get the lines like before, seems that LCD is not detected now.
Check if 3V3/5V_S0SW_LCD are present at J8500 at least; DP_INT_HPD should go high too.
 
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