LENOVO G50 -70 power on No screen

[ghost73]

Hello from Greece
I have problem with Lenovo g50 -70
power on but i cannot see nothing in screen
please check the picture .. is this OK ?

[sicilianul]

Re: LENOVO G50 -70 power on No screen

That one is PR306 and should have 200KΩ

Anyway - it should power on and see something on display. what you have in picture is from battery charging. Works independently that part.

[ghost73]

Re: LENOVO G50 -70 power on No screen

i have 200ΚΩ

[sicilianul]

Re: LENOVO G50 -70 power on No screen

Here is schematic.

[ghost73]

Re: LENOVO G50 -70 power on No screen

I put a ligth in screen and i see activite . but the backlight dont work and i dont see the lenovo logo.
blinking a dim light

[ghost73]

Re: LENOVO G50 -70 power on No screen

Thank you for the schematic.

[ktmmotocross]

Re: LENOVO G50 -70 power on No screen

as first flash bios. have many of it with bad bios program

[lapfix]

Re: LENOVO G50 -70 power on No screen

So you see picture but no backlight !..do you try on external display !
can you take this measurement on JEDP1 : Pin 1/2 , Pin 21/22 , Pin 2 Q8

[ktmmotocross]

Re: LENOVO G50 -70 power on No screen

I put a ligth in screen and i see activite . but the backlight dont work and i dont see the lenovo logo.
blinking a dim light

What means "Activite"?

[ghost73]

Re: LENOVO G50 -70 power on No screen

So you see picture but no backlight !..do you try on external display !
can you take this measurement on JEDP1 : Pin 1/2 , Pin 21/22 , Pin 2 Q8

I try with external display ... but not work
PIN 1 20.1V
PIN 2 20.1 V
PIN 21 3.4V
PIN 22 3.4V

pin 2 q8 ???

[lapfix]

Re: LENOVO G50 -70 power on No screen

No need now for pin 2 of q8 since you got 3.4 at pin 21/22 , sorry to not ask for this before : pin 20/23 for 3vs ..if you got it than try another screen and /or another screen cable...if no backlight than try flashing bios .

[sicilianul]

Re: LENOVO G50 -70 power on No screen

I had a lot of lenovo with this type of problem. I just disconect lvds cable from display, reconnect back and everything is back to normal.

[ghost73]

Re: LENOVO G50 -70 power on No screen

No need now for pin 2 of q8 since you got 3.4 at pin 21/22 , sorry to not ask for this before : pin 20/23 for 3vs ..if you got it than try another screen and /or another screen cable...if no backlight than try flashing bios .

i try it but i have the same problem .
how to flash the bios with this problem ... ?

[lapfix]

Re: LENOVO G50 -70 power on No screen

What about pin 20/30V !
To flash bios you must have/buy a mini programmer ( google it )

[String2016]

Re: LENOVO G50 -70 power on No screen

did you check the fuse near the lvds connector?

[ghost73]

Re: LENOVO G50 -70 power on No screen

What about pin 20/30V !
To flash bios you must have/buy a mini programmer ( google it )

pin 20 0v

i try to find the R21

[kiraro]

Re: LENOVO G50 -70 power on No screen

R21 and C22 doesn't exist, if there is no short on pin 20 try to make a jumper from 3VS to this pin and see if there is a picture .

[ghost73]

Re: LENOVO G50 -70 power on No screen

R21 and C22 doesn't exist, if there is no short on pin 20 try to make a jumper from 3VS to this pin and see if there is a picture .

take a look..

[lapfix]

Re: LENOVO G50 -70 power on No screen

3Vs appear after switshing power button ,this is your S0 satate.It supply many others IC's .
why you don't have it on pin 20/23 !!
can you take the measue of Q24 ( D/G/S) and see like Kiraro says if thers is a short on it !

[ghost73]

Re: LENOVO G50 -70 power on No screen

i make a jumper and i have this action from the screen ... no backligth and one horizontal line blink every 3 or 5 second ....