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How do I just power the backlighting on a broken lcd tv? Answered

I have a busted lcd tv that the backlighting still works but i would like to get rid of stock power supply and input box. In essence make it into a light table. The plug that powers the inverter for the CFLs has 9 wires 5 red 4 black and is marked 24v. now here comes the crazy question can i wire in a 24v adapter with a simple on/off switch. Any help will be greatly appreciated. 


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Jack A Lopez
Jack A Lopez

10 years ago

Um, yeah... it probably really is that simple. Supply 24 VDC, with the correct polarity,  at the requisite amount of current, unto your backlight, and it will glow like it did with its old power supply. In fact you could even use it with its old power supply. Make the wires longer if you want to.

By the way, you should go over this thing with your multimeter, and make sure that it really is wired the way your hypothesis. 

You know, with the power turned off, use the ohmmeter setting to check and see if those wires, and pins,  are really all tied to just tied to one or two nodes the way you think they are.  Are all the red wires really connected to each other, like you suspect?  Are all the black wires connected to each other, like you suspect? 

Next turn the thing on, and carefully, check the voltage across these two nodes. Is it really 24 VDC? Is black ground (0 V), and red +24 V? Or did they reverse the colors for some damn fool reason? The voltmeter will tell you.

Next. Turn it off. Take it apart. Wire an ammeter in series with it.  Then turn it on, and measure the current, in amperes, drawn by the backlight. This is useful information to know, especially if you really want to go through with your original ideal of replacing the stock power supply with a new one.  When you go shopping for your new 24V supply, or searching through the junk box for one, you will know how much current it must be capable of supplying.

Anyway, something you should take away from all this is that via the use of a good multimeter, and um, your brain, you can solve little puzzles like this yourself, and you really didn't need to ask the Internet for help.  

It's just like the ending of the Wizard of Oz, where you learn that you actually had the thing you thought you lacked the whole time. So there.