820-3115-B No Backlight

[2informaticos]

Connect LCD and check Q9706 voltages!
Can't diagnose backlight circuit without LCD.

2V on backlight output was found with LCD connected?

 

[mushr00m]

q9706

All pins are 12.56 volts with LCD connected

backlight output measure on A5/U9701 using the charger instead of battery now its 4V tries to increase to 8V and drops to 4 and incrasse again..

 

[2informaticos]

Post Q9707 voltages now.

Do you still get image on LCD?

 

[mushr00m]

Yes it still has image but no backlight all the time since the beginning

Q9707

PIN1 = 0
PIN2 = 3.2
PIN3 = 0
PIN4 = 0
PIN5 = 3.2
PIN6 = 0

Whats next now???

 

[2informaticos]

"q9706
All pins are 12.56 volts with LCD connected"
Are you sure?
Pin 3 should have 4V aprox.

 

[mushr00m]

Sorry mistake

I went to check the PIN which gave 0V at first since the LCD was not connect

Just checked PIN3 and its 4.3V

What's next now? Still didn't repair this notebook

 

[2informaticos]

Post D9701 voltages (LCD connected).

 

[mushr00m]

It the same as the output which I gave you earlier

It starts with 2V and keeps increasing then when its almost 6v its goes back to 4V and start increasing again... A bit weird!

REMEMBER: The cap below D9701 was the where the short was C9797

And nowww whats next?

 

[2informaticos]

I asked about "voltages".
That diode has 2 pins; do we know if you have the same voltage on both?

Check R0910 and traces.

 

[mushr00m]

Sorry let me write it in a better way

D9701

PIN1 = It starts with 2V and keeps increasing then when its almost 6v its goes back to 4V and start increasing again...
PIN2 = It starts with 2V and keeps increasing then when its almost 6v its goes back to 4V and start increasing again...

What now?

 

[2informaticos]

"Check R0910 and traces."

 

[mushr00m]

Nailed it boss!

Its was R0910. Replaced it and backlight back to business

Thank you very much for your support!