LCD lamps Checker
2010-06-07
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In this article we describe how to build a tester CCFL backlight lamps or cold cathode.
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Inthis article we describe how to build a tester CCFL backlight lamps or cold cathode.
As we all know most of the damage suffered from the LCD TV are caused by the inverter or the power supply, a small part is produced by the main board and a fraction are the lamps.
To make a rapid diagnosis when we have a backlight fault we could very well rule out the lamps as soon as possible to avoid manipulation of the inverter or power supply.
The most typical symptom in damage caused by backlighting is that we image a second or two and then the image is dark for lack of back lighting.
In this situation the first thing would be to check the inverter and the tensions of this. However, not all problems of the inverter is sometimes, and we can go crazy trying to repair an inverter that really works well. If in this case we had a bad lamp, the symptom is the same as if the inverter is not working properly. For this reason it is best to discard the bulbs first.

We will build our tester lamps. This time we have to create a single lamp tester, although we could build a tester to test two or more lamps at a time.
Use:
"An inverter with a single output
"Three batteries for power 4V
"A button

The inverter we can get some scrapping or directly monitor what we buy.
The batteries should provide enough power, these we use are available on the market, although I've got a laptop battery that did not use.
Any button that is a little small we had better.

Start:

1 .- We connect the three batteries in series to achieve a common voltage of +12 V.
2 .- We feed the inverter with these +12 V. The positive we can supply welded in the positive filter capacitor is the inverter and the battery negative to the negative of the capacitor. With this we have the inverter fed.
3 .- With reference to the negative power cable soldered to the first battery, which we'll get 4V voltage used as ON / OFF. In this lead solder one leg of our switch and solder another wire to the other leg of the push that's going to pin ON / OFF of the inverter. The next thing is to find this pin in our inverter. In our case the pin 2.
Now we just have to try a lamp and close our push to see if the lamp is lit.
Indeed our lamp is lit.
We have built our tester lamps. There is now only assemble all the parts that are not loose. In my case I have done with electrical tape to create a compact block.
When testing this device will see that lights up the screen with each lamp try. If, however, does not illuminate, is that the lamp is bad.

Hope you might help.
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