toshiba satellite p755-s5295

[mazloum]

phqaa la-6832p rev: 2.0
hi
the customer was replacing broken screen with battery on, now the laptop has no display on the screen of the laptop, but it displays every thing good on external monitor...
i changed Q1 with no success

[mazloum]

Re: toshiba satellite p755-s5295

can i just insert 3.3v on lcd_vdd for test?

[Sephir0th]

Re: toshiba satellite p755-s5295

You checked R107 is fine? Ohms Reading of this rail?

[mazloum]

Re: toshiba satellite p755-s5295

yes, r107 is 150 ohm

[Sephir0th]

Re: toshiba satellite p755-s5295

Show Pic(s) of the LCD-connector and also Share Résistance to GND of +LCD_VDD Rail.

[mazloum]

Re: toshiba satellite p755-s5295

Résistance to GND of +LCD_VDD is 296 ohm

[mazloum]

Re: toshiba satellite p755-s5295

any one?

[Sametbey]

Re: toshiba satellite p755-s5295

Check the Q17 LCD_VDD transistor in the second picture first. When ENVDD 3v arrives ( Q1A-B ), Q17 G pin will be 0.6v, P_chanal mosfet will transmit.

[mazloum]

Re: toshiba satellite p755-s5295

i have 2v on gate of Q17
3v on D
and 3v on s

[Sametbey]

Re: toshiba satellite p755-s5295

In the first picture, you have written LCD_VDD missing. Q17 supplies LCD_VDD voltage to the LVDS socket.
Q17 D pin has 3.3v? it should go to the LVDS socket if there is one.

[mazloum]

Re: toshiba satellite p755-s5295

this is the problem....
pin 6 voltage on Q1 is missing

[Sephir0th]

Re: toshiba satellite p755-s5295

You don't Understand. Q1 Pin6 and Q17 Pin1 ist the Same Rail! So your shared measurements are wrong!

Double Check!

[Sametbey]

Re: toshiba satellite p755-s5295

Measure starting from ENBVDD. 1 position, 2 positions

[mazloum]

Re: toshiba satellite p755-s5295

You don't Understand. Q1 Pin6 and Q17 Pin1 ist the Same Rail! So your shared measurements are wrong!

Double Check!

i will try

[mazloum]

Re: toshiba satellite p755-s5295

ok i have all volts now, but no display...
i changed the lcd cable also , with no success

[Sametbey]

Re: toshiba satellite p755-s5295

Do you have + 3VS and LCD_VDD voltages for the Panel ? 6 and 8 pins exchange data between the LCd panel and the PCH. For panel detection. check the signal backwards. and 10 pin LEDPWM need to be 12 pin BKOFF 3,3 v. maybe panel.