Riddled TV Repair Forum

jackietan · Joined: 28 Jan 2017 Posts: 6

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

Google

jackietan · Joined: 28 Jan 2017 Posts: 6

TV

LED Driver Board

Main Board

Power Supply Board

Fluke

JTS1957 · Joined: 21 Jan 2009 Posts: 2395 Location: Far, Far Away

Never have given Brand/Model info. YOU are the one requesting help.

Google links all give ...
"Google: 404. That’s an error.
The requested URL was not found on this server. That’s all we know."

A more mainstream photo-sharing service (Imgur - Photobucket, etc.) where viewers don't have to setup 'accounts.'

Utub video refers to a 65" Vizio. Two boards come up as Panasonic. Third board would tend to reference a 39".

jackietan · Joined: 28 Jan 2017 Posts: 6

Hi, thank you for remind about the link not working. I have upload the proper link with photos shown. Can you advise me what can I test for the TV. Thank you

kuhurdler · Joined: 28 Dec 2006 Posts: 2879 Location: Overland Park, KS

I updated the title with the correct model number, symptoms. I'm no expert on this one, but I've never seen a resistor like that from the factory.

Google

jackietan · Joined: 28 Jan 2017 Posts: 6

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.

JTS1957 · Joined: 21 Jan 2009 Posts: 2395 Location: Far, Far Away

If we wind up getting this power supply back up, please back-probe the connectors for your future voltage measurements (as I've mentioned on this forum).

You may have gotten lucky...
Looking at the rear of P2 on the power board, it appears that pins 1 & 2 (?36V?) may be the same point and that pin 3 looks like it goes to ground (IF pins 1 & 2 ARE the same points, that should mean pins 11 & 12 (?36V?) on the Main board A09 and pin 10 is ground). There is a surface mount fuse (F7402) that may have opened on rear of Power board. If it is open measure the resistance to ground to BOTH of its terminals (one at a time) to see if there is a short either inward (PS board - Q7403 for example) or outward (Main board).

SJ photos also show F7101 ceramic and F7401 fuses on PS that also should be checked for continuity.