Hello
RAEQUINTERO,
The problem you described sounds like either your inverter or
back-light has malfunctioned. There is a way to test this. Turn your TV set on and in a dark room shine a flashlight onto the screen and see if you can make out a faint image of a picture. If you can this means that the
back-light or the inverter has malfunctioned. Now at this point I should tell you if either of these has failed you have to make sure to check if the
back-light, inverter and LCD screen are not one unit, because if it is the screen with the inverter and
back-light will cost as much as the entire TV. If the screen inverter and
back-light are separate devices then you will only have to replace the defective part. These are the pieces of equipment and documentation that you will need to properly repair this problem:
1) The schematic for the TV try
www.servicemanuals.com
2) A Multimeter To measure the voltage levels and bias voltages of the inverter and
back-light inputs and outputs
3) Signal generator To establish a know good test signal for proper
measurements
4) Oscilloscope To measure wave
patterns from the Video output feed.
Use the schematic to show you what the voltages should be at different points on the
back-light and the inverter. Use the multimeter to measure these bias voltages and voltage levels on the
back-light and inverter pins and board connections. Use the signal generator connected to the F connector of the TV to establish a known good signal to the TV. Then use the oscilloscope to
measure and view the video signal levels and the data stream that form the picture.
You may have to do a lot of removal of boards to get the the LCD
back-light and inverter, however the schematic will help you with this (Remember to mark all cables for easy reinstallation).
This is the way to do this if you are going to attempt this yourself. If not please have a qualified TV
repair-person give you an estimate of cost and have them repair the TV set.
I hope this helps
Thank you,
Shuttle83
×