Alienware M17X R2 AB 4400 - no backlight

[ktmmotocross]

Hello.
Have this Alienware M17X R2 AB 4400 on i cannot enable BKL. Ha two displays one with CCFL and othe with LED backlight
Attach my readings. i try to even inject missing PWM and BKL power but not work

[Rhadu23]

Re: Alienware M17X R2 AB 4400 - no backlight

Hello,

Are you sure them displays are working?

Also, make sure the display cable is well sited in the socket.

I have the same Alienware and had same issue with it and turned out to be the cable not properly sited.

[ktmmotocross]

Re: Alienware M17X R2 AB 4400 - no backlight

Hello,

Are you sure them displays are working?

Also, make sure the display cable is well sited in the socket.

I have the same Alienware and had same issue with it and turned out to be the cable not properly sited.

eah i know that. dont know if both screen are good. but have picture and no backlight on it. one of it is brand new

[SMDFlea]

Re: Alienware M17X R2 AB 4400 - no backlight

Test voltage on R21 , check for any activity on Q17,Q19 pins 1 and 3 on both,and attach the keyboard and try the brightness setting FN whatever

[Rhadu23]

Re: Alienware M17X R2 AB 4400 - no backlight

also try to reset the display by press the Windows logo key, the Ctrl key, the Shift key and B at the same time

[ktmmotocross]

Re: Alienware M17X R2 AB 4400 - no backlight

Test voltage on R21 , check for any activity on Q17,Q19 pins 1 and 3 on both,and attach the keyboard and try the brightness setting FN whatever

this could not be on full brightness on start?

R21 no voltage, but i try to inject and no joy

Q17 have 0.17V on pins 3 and 1 , 3.3V on pin 2
Q19 have 0.0V on pins 3 and 1 , 3.3V on pin 2


i foung SMBCLK1 and SMBDAT1 shorted. 1.2ohm to GND when off and 13.5ohm to GND when started

[ktmmotocross]

Re: Alienware M17X R2 AB 4400 - no backlight

What is normal resistance so i can track the problem?

[SMDFlea]

Re: Alienware M17X R2 AB 4400 - no backlight

What is normal resistance so i can track the problem?

Don`t know . If theres no voltage on SMBCLK1 it could be a problem with the EC .

[ktmmotocross]

Re: Alienware M17X R2 AB 4400 - no backlight

i think u have right. no SMB mosfets is shorted and i found little burn mark on EC

[ktmmotocross]

Re: Alienware M17X R2 AB 4400 - no backlight

i found chip with same marking so i try to replace it

[ktmmotocross]

Re: Alienware M17X R2 AB 4400 - no backlight

looks like it worked. Inverter WORK and even Fans work normal

but there is another weird problem, that start after EC change
MAIN_PWR_SW# go only to 2.2V when i press pwrbtn so it not start

Before R6 3.3V go to 0.0V when press button, but after R6 it it go only to 2.2v

when i short after R6 to GND laptop start.

R6 and R3 have measured the right restance

[SMDFlea]

Re: Alienware M17X R2 AB 4400 - no backlight

Your original chip is marked JXD ,your replacement is DXS .See if you can get one exactly the same

[ktmmotocross]

Re: Alienware M17X R2 AB 4400 - no backlight

dont have that. i must order one



Replaced R6 - 10K with 4.7K and now MAIN_PWR_SW# does down to 0.22V and laptop start

for now i test it if it have any other issues because of different ic

[ktmmotocross]

Re: Alienware M17X R2 AB 4400 - no backlight

so far everything works