(347) 552-2258 [email protected]

820-01987

I

iFix

Member
Hi.

I have this board with no backlight and no image, but powers on and works on external without any issues. I have voltage on Q8400 pins 3 and 4 and no short circuit anywhere, but I'm missing EDP_BKLT_EN on pin 1 on R8442. CPU not sending signal?
 
I

iFix

Member
DP_INT_HPD 3.3v

3V3/5V_S0SW_LCD 3v and 5v

This laptop without a battery connector turns off so the voltages go down after a bit. Anyway, there's no image besides the backlight, as mentioned above.


Anything else I need to measure because I checked the whole connector diode mode all is good
 
I

iFix

Member
Also, The laptop is clean as new no liquid or burned components etc. The client only dropped it some time but nothing serious and he was using it few months like that, just now it decided to stop
 
2informaticos

2informaticos

Administrator
Staff member
"LID_OPEN_RIGHT 0.8V"
You have a problem with right lid sensor; placed on speaker cable.

Remove R4805 and tie together pins 1 & 2 of U4802.
Check if this helps...
 
I

iFix

Member
I just rechecked now and LID_OPEN_RIGHT stays at 0.85v even when pins 1 & 2 of U4802 are connected. All other signals are 1.8.

LID_OPEN_RIGHT goes to U6650, but no info about the chip on the schematics. Not sure if U6650 is on the board, under the shield which covers U7800.
 
I

iFix

Member
Because R4805 is removed and on pin 1 I have 0.85v, and on pin 2 I have connected R4804 pin 2 which has 1.8v. You said to remove R4805 and connect pins 1 & 2 of U4802
 
I

iFix

Member
No problem, I will try. In the meantime, the backlight chip decided to stop working and shorted half of the board. I need to replace it and try again. No short when the backlight chip is removed. I will update asap
 
I

iFix

Member
I replaced the backlight chip and wired 1.8v from LID_OPEN_LEFT to LID_OPEN_RIGHT , and still the same. SMC_LID_LEFT/RIGHT are 1.8v also as they were even before
 
2informaticos

2informaticos

Administrator
Staff member
Keep the mod for lid signals; because you have bad right lid sensor.

Check diode mode to ground on EDP lines of J8500.
 
I

iFix

Member
EDP_AUXCH_N - OL
EDP_AUXCH_P - 0.219
EDP_ML_N<0> - 0.210
EDP_ML_P<0> - 0.216
EDP_ML_N<1> - 0.216
EDP_ML_P<1> -0. 216
EDP_ML_N<2> - 0.216
EDP_ML_P<2> - 0.216
EDP_ML_N<3> - 0.216
EDP_ML_P<3> -0.216

EDP_PANEL_PWR_BUF_EN - 0.574
DP_INT_HPD - 1.611
EDP_BKLT_PWM - 0.788
PP5V_S0SW_LCD - 0.544
PPVOUT_S0_LCDBKLT - 0.842
PP3V3_S0SW_LCD - 0.474
 
You must log in or register to reply here.
Top