TV Repair

[hawk77]

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
https://www.youtube.com/watch?v=YCmguR57fVM&index=4&list=PLzCYXKYj3Q5tVpWqd3SFrQ17Ap0hAq-pX

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

TV

TV

TV

LED Driver Board

LED Driver Board

LED Driver Board

 

[hawk77]

LED Driver Board

LED Driver Board

Main Board

Main Board

Main Board

Power Supply Board

Power Supply Board

Fluke

 

[darkarn]

That squarish port from the Main Board is a Toslink port; it transmits audio signal using light, hence that red light.

This may mean that it is possible to have audio from that port, just need to get a Toslink to analog converter (easy part) and make the TV use Toslink to transmit audio (the hard part)

EDIT: Erm, ok I see. What have you done so far other than opening up the TV? (Am unsure how you manage to short circuit the TV...)

 

[wwenze]

How did you even perform the short and what are those pins supposed to be carrying anyway.

So summary: Pin3 was shorted to pin2. Sparks flew at connector of pin3 of connector P2.

Check whether the fuse has blown. Disconnect all cables and apply power and check for standby voltage. You'll need more pictures than this - at least show what the pins of connector P2 are connected to.

TBH, apart from blown fuses, there is no repair that can be done economically. Even if the problem was just no backlight, a board replacement is easily in the 3-digits.

 

[||||||||||]

Wait for commach to advise lo....


But I find it funny that you even post your multimeter pics.

 

[harky]

wow.. dunno the LED tv is maintain by 4 board

 

[hawk77]

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.

 

[wwenze]

Hard to believe the main board runs on 36V. Even harder to believe that there would be 36V difference between main board pin 1 and power supply pin 1 if those pins are connected together.

If there is no more voltage from the PSU, just return it to the garbage where it belongs.

 

[harky]

I saw some Ppl actually sell the electronic inside.. Not sure led TV they want a not. I sold my CRT to one person and he open up, take the thing inside and throw away the casing

 

[peterchan75]

The fuse F7101 on the power board might be blown. Need to desolder the fuse and check. Before you put in the fuse, check the 3 power transistor with heat sink and see if the plastic package is burnt. Likely that one or two are bad. Sometimes the fried power transistors might fried the logic board.

 

[86technie]

Not worth your time since brand new HD cost as low as $500 already.
If you get quote from Panasonic service center, easily few K one
since panel and mainboard may need to replaced.
Not to mention MTBF may hit it's lifespan already.
New one is already so cheap don't really need to savage
unless you are planning for DIY.
If not can go for non-HD TV, cost around $3XX onwards.

There is a reason there's a disclaimer stating:
"Refer servicing to qualified service personnel only."
Since you have somehow shorted the circuit, it may
do more damage than good.

Even if you manage to jump start the main circuits,
if the main TV panel is already gone no way to fix the panel.