CTL51/53 LA-E831P No Display problem

[battery.12v]

HP LAptop : CTL51/53 LA-E831P Issue: Laptop turn on OK but No Display ... External Display HDMI works fine... i changed the whole LCD assembly with the ribbon cable and still same issue, its not a Backlight issue cause i raise led backlight to full 3.3v with the PWM and still nothing displayed on screen ... LCDVDD is High, 19Volt PResent and another 3.3v is present also ... LID_SW# is high ... its a discrete Motherboard ... and Schematic Unavailable ... Could it be a BIOS issue ??

[peste]

Re: No Display problem

if the external screen works, it is not bios ...

[battery.12v]

Re: No Display problem

if the external screen works, it is not bios ...

Emmmm, So what could be Wrong ??

[peste]

Re: No Display problem

see the video chipset..

[battery.12v]

Re: No Display problem

see the video chipset..

External Display Monitor Work Fine !! isnt that a meaning that my graphic card is good

[mcplslg123]

Re: No Display problem

No. that doesnt guarantee that the video chipset is ok. Usually when a video chipset is about to die,this symptom of getting display on external but nothing on internal screen happens. You can try a mild reflow of the video chipset with lot of goodquality flux. Dont heat too much to kill the chip.

[battery.12v]

Re: No Display problem

No. that doesnt guarantee that the video chipset is ok. Usually when a video chipset is about to die,this symptom of getting display on external but nothing on internal screen happens. You can try a mild reflow of the video chipset with lot of goodquality flux. Dont heat too much to kill the chip.

Do this Heating Stuff work even on this new generation Laptops ??

[Gimi]

Re: No Display problem

i dont work on laptops,macbooks only but backlight 3.3v sounds to low for me to say its ok to have backlight working. all them led diod lights there need more to light up. id say its backlight , do not heat the board. check bklight for short first

[battery.12v]

Re: No Display problem

i dont work on laptops,macbooks only but backlight 3.3v sounds to low for me to say its ok to have backlight working. all them led diod lights there need more to light up. id say its backlight , do not heat the board. check bklight for short first

i bypassed the backlight thing using a flashlight but no luck ... when power on screen seems like turning on but nothing happen stuck on no display

[Vesko356]

Re: No Display problem

i dont work on laptops,macbooks only but backlight 3.3v sounds to low for me to say its ok to have backlight working. all them led diod lights there need more to light up. id say its backlight , do not heat the board. check bklight for short first

3.3v LED_EN and PWM are control singnals.

@battery.12v - when outputting on external screen do you tried on keyboard windows key + P combination to switch picture to laptop screen?

Measure voltage on lvds connector, pin 35 to 40 and 2,3 and 4, and tell me what is the values.