TV Repair

[jackietan]

I pick up a TV from the garbage. At first, I turn it on, the LED green light is on, blink for 9 time. There is no sound, no picture, no backlight, I use a flashlight, there is tv manual image at the dark panel. It is strange that there is a resistor weld at the LED driver board (shown at photo). There is red light on the Main board Digital Audio Out when the TV is turn on. From the shopjimmy.com youtube video, it is most likely the LED driver board but it is strange that there is a resistor welded.

I tried to do a voltage test from the shopjimmy.com reference video


Between the Power Supply Board to the Main board, I think I have accidentally short circuit the 2nd and 3rd pin on the Power Supply Board to the Main board 2nd pin. There is a spark on the 3rd pin of the Power Supply Board during the short circuit. Now there is no sound, no picture, no backlight, no start LED light, no red light on the Main board Digital Audio Out.

Can you advise me what test I can do before decide which board to replace. I'm not a professional, if you can provide the instruction to test what is spoilt during the short circuit, eg diode, capacitor.. I have a Fluke 175 multimeter to test. Below are the board part number. I provide some reference photos. Please let me know if I need to provide more photos. Thank you.

LED Driver Board
L390H1-1EE

Power Supply Board
TNP4G532

Main Board
TNP4G530

[jackietan]

TV

TV

TV

LED Driver Board

LED Driver Board

LED Driver Board

LED Driver Board

LED Driver Board

Main Board

Main Board

Main Board

Power Supply Board

Power Supply Board

Fluke

[jackietan]

I provide more information below.

Firstly the TV pick up from the garbage when turn it on, the LED green light is on, blink for 9 time. There is no sound, no picture, no backlight, has an image on screen with flashlight. This conclude that most likely is the LED drive board need to be replace.

But when I accidentally short circuit the 2nd and 3rd pin on the Power Supply Board to the Main board 2nd pin, there is no sound, no picture, no backlight, no start LED light, no red light on the Main board Digital Audio Out.

I provide three photos below for reference

Power Supply Board To Main Board


Power Supply Board


Main Board
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Before the short circuit 2nd and 3rd pin on the Power Supply Board to the Main board 2nd pin, I test voltage the 1st pin on the Power Supply Board to the Main board 1st pin, I think I saw 36 DC voltage if I'm not wrong. When my test probe touch the 2nd pin on the Power Supply Board to the Main board 2nd pin, I accidentally short circuit the 2nd and 3rd pin on the Power Supply Board to the Main board 2nd pin because my Fluke test probe tips is quite thick.

Is there anyway to test what item maybe spoilt before conclude to change the whole Power Supply Board, Main Board and confirm spoilt the LED driver board. Is there a way to find out either the Power Supply Board or Main Board is spoilt, rather than change both that one of it maybe ok from the incident.

Thank you for your help.

[james_s]

Did you try unplugging it for a few minutes and then plugging it back in? There's no telling exactly what damage was done by shorting those pins, but if you get stuck it's usually pretty easy to find replacement boards for TVs. Quite a few get cracked screens from getting knocked over or kids throwing things. You've got a good screen there that just needs a board. If you can get it to power up again, the LED driver board looks like it has a bunch of individual buck or boost converters.