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Laptop Backlight problem, Inverter works

kahlenberg

Mar 9, 2014
1
Joined
Mar 9, 2014
Messages
1
Hi,

I have a Toshiba Satellite U405D laptop and now there is no backlight. My friend has also the exactly same model and I tried the inverter, LCD display and cable. All of them work. Maybe there is an issue with grapics chip but I am not sure and I dont have any special device to remove it solder it back.

I tested the connections on the inverter. I saw that inverter has 4 connections, 2 for power (18V, GND) and two another connections (I think one for ADJ, and one for ON signal).

My question is: Can I make a small circuit with SMD componenst for the ADJ an ON signals? If yes how? What a signal does the inverter wait from those inputs?

Thanks.
 

KrisBlueNZ

Sadly passed away in 2015
Nov 28, 2011
8,393
Joined
Nov 28, 2011
Messages
8,393
Hi and welcome to Electronics Point :)

The ADJ signal is probably just a variable DC voltage that sets the brightness of the backlight. Instead of making a circuit to feed a voltage into the ADJ input, how about measuring the ADJ and ON voltages on your machine and your friend's machine. Is it possible that you've accidentally pressed some Fn key combination and switched the display to the external monitor connector, or turned off the backlight?
 
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