dell inspiron N7110 LCD no back light

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bigsam731

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Oct 7, 2016
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Hello all. I'm new to the community and my apologies if this was discussed in a previous post. I have a Inspiron 17R N7110 that has dim backlight to the LCD. When I plug it it to an external monitor i can see everything in that monitor. I searched every where for a solution but nothing on my model, all I find is solutions for the 1545 model which tells me to replace the F1 or F8 fuse. If that's the case on mine, does anyone know where are those fuses located? thanks in advance

My motherboard model is
DA0R03MB6E0 REV; E
 
This is the reading that I got in the LCD side of the cable:
Pin 40 19V
Pin 36 19V
Pin 35 3.1
Pin 4 3.3V
Pin 2 3.38

i also retested the motherboard connector side and I got the same results on all above pins.
 


I remeasured again and I got 18.9V on pin 36 of the LCD connector on both sides of the cable. Also I got 3.1V on pin 3 of the JP1 connector. just to be sure the JP1 is the connector for the mouse pad correct?
 
Yes, JP1 is connected to the mouse pad and also for our need the lid switch. The only different voltages are on the pin 36 of the LCD connector. I don't have the datasheet for the Embedded controller for your laptop, so I extrapolate the voltage from a similar one.
 
Sorry, but not quite true,on page 23, the wire from R203 which goes to pin 21, you have a red dot, that means that both wires are interconnected. You do not have a red dot between the wire from R203 and the pin 18 and pin 125, so they are not interconnected. But you should have 3.3 volts because the pin 18 is an output voltage and supplying this chip is 3.3 volts. I could be wrong, but until someone corrects me, this is my interpretation.
 


No they are connected. I just don't know what powers pin 36.
 


On one side i get 19V and the other i get 1.4V
 


Yes it is, otherwise as soon as I turn on the machine it gives me 8 beeps for no screen connections or LCD failure. Also I still get no back light when I try a different LCD. I tried my LCD in a different laptop and it works just fine.
 
From the specifications of your screen, on pin 36 you should have 3.3 volts for the screen to be enable. I think the chip (IT8518) on page 23 who control this pin is defective. A test you can perform, but this is on your own if something goes wrong, but trust me, you have to open the wire for the pin 36 on the cable from the motherboard, and connect this wire going to pin 36 to the screen to the pin 2 off the connector, in that way you give 3.3 volts to pins 36 for the screen from pin 2.
 
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