Toshiba L850-B387 (external display ok internal not coming)

[SR IT SOLUTION]

Hi all,
i have Toshiba L850-b387
part no : PLF/PLR/CSF/CSR DSC MB REV:2.1
the problem is external display on monitor is ok, but
no display comes in laptop screen
any one help??

[mcplslg123]

No measurements posted and you expect help?

[Stevedb]

First measure te on display connector if you got ,main power rail and 3,3✓

[SR IT SOLUTION]

No measurements posted and you expect help?

LVDS connector measurements
pin 2--19v coming
pin 36 --lcd_bl_pwm_c not present
pin 38 and 40-- +Lcd VCC not present
PIN 39-- +3VS PESENT

[Stevedb]

And whitout screen connected always disconnect battery when you Mess with connectors.

[mcplslg123]

U4501-voltage on all pins?

[SR IT SOLUTION]

U4501-voltage on all pins?

u4501--- only 5 number pin 3.3v
rest of pins--0 v

[mcplslg123]

Check R4512/13 for value. Post the voltage on both sides of these resistor. What is the resistance to GND on pin1 of U4501?