back light problem on my acer es1-511

[Akhilesh_5]

my backlight has stop working can you help ???????????

 

[jarotech]

If I follow the procedure you did to measure the voltage on the L4 coil. You connected the adapter to the motherboard, you push the power button, you don't have a picture on the screen of the laptop, you measure no voltage on the L4 coil, but you have something on an external monitor.

 

[Akhilesh_5]

Yes where can i get the L4 coil ??

 

[jarotech]

But the problem is not the coil if you have no voltage on both sides.

 

[Akhilesh_5]

what is the problem

 

[jarotech]

To ensure that the measurement is valid, you measure the voltage of one side of the coil and the ground when the laptop is powered.

 

[Akhilesh_5]

yes i measure with ground also

 

[jarotech]

The L4 coil supplies the voltage to the backlight of the screen, the voltage comes from the adapter or the battery through a transistor to the whole motherboard, it is called B+. Somewhere a trace is open or you have a bad solder, this is why you have no voltage to the coil. You must follow the B + (about 19 volts) to see where you lost the voltage, it should be around the coil L4 because everything else of the motherboard gets the power.

 

[Akhilesh_5]

now its working i get voltage reading 16.05v in both sides

 

[Akhilesh_5]

but i dont get any back light ??

 

[jarotech]

You should also have 16 volts on the pin 1 at the LCD connector, if you have the voltage, verify the cable for the screen, reseat the cable on the back of the screen.

 

[Akhilesh_5]

it doesnt do on the pin 1

 

[jarotech]

If you have 16 volts at the coil on both sides and no voltage on pin 1, look if the trace between the two is cracked.

 

[Akhilesh_5]

now voltage is coming on pin 1

i have tested the lcd cable
it is working perfectly

but there is no back light

what should i do now ?

 

[jarotech]

If you have the voltage at pin 1 and the cable is good, logically the problem is the screen. You need a new one.

 

[Akhilesh_5]

i have tested a new screen on my laptop its the same

 

[jarotech]

So, you repair laptops, if you have a spare screen? What voltage do you have at pin 4 on the U11 chip?

 

[Akhilesh_5]

where is the U11 chip found?

 

[jarotech]

 

[Akhilesh_5]

It Doesn't have any voltage

 

[jarotech]

Measure the voltages on pin 1, pin 2 and pin 5, on the same chip U11.