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jackietan
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Jan 28, 2017, 4:44 PM

Post #1 of 13 (7495 views)
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TV Repair	Can't Post

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

(This post was edited by jackietan on Jan 29, 2017, 6:51 AM)

jackietan
New User

Jan 28, 2017, 5:20 PM

Post #2 of 13 (7488 views)
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TV Repair [In reply to]	Can't Post

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

(This post was edited by jackietan on Jan 29, 2017, 6:49 AM)

jts1957
Veteran

Jan 28, 2017, 6:22 PM

Post #3 of 13 (7480 views)
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Re: [jackietan] TV Repair [In reply to]	Can't Post

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

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

1 ohm resistor connects between ground and Q112 collector (which also connects to I.C. U9 ATP360A13) in a prior attempt to restore backlights?

Have not been able to locate any service literature (yet). I have located a Pana that uses same LED board but is a U.S. model.
Digital Audio out red light is normal.

-------------------------
Location: Far, Far Away

(This post was edited by jts1957 on Jan 29, 2017, 9:20 AM)

jackietan
New User

Jan 29, 2017, 12:26 PM

Post #4 of 13 (7438 views)
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Re: [jts1957] TV Repair [In reply to]	Can't Post

[quote="jts1957"]Never have given Brand/Model info. YOU are the one requesting help.

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

1 ohm resistor connects between ground and Q112 collector (which also connects to I.C. U9 ATP360A13) in a prior attempt to restore backlights?

Have not been able to locate any service literature (yet). I have located a Pana that uses same LED board but is a U.S. model.
Digital Audio out red light is normal.

Hi, thank you for giving some reply on the post that I ask for some advise for TV repair. There are some words / sentence I do not understand and will like to check.

"Never have given Brand/Model info. YOU are the one requesting help"
To check what is this sentence referring to?

"Utub video refers to a 65" Vizio. Two boards come up as Panasonic. Third board would tend to reference a 39"
The youtube video is only as an reference. When I test want to test the voltage from the power supply board to the main board, I have accidentally short circuit the 2nd and 3rd pin on the Power Supply Board from my Fluke test pin.

"1 ohm resistor connects between ground and Q112 collector (which also connects to I.C. U9 ATP360A13) in a prior attempt to restore backlights"
I do not know why there is a 1 ohm resistor at the LED driver board, it had been there when I pick up TV from garage. 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. I search YouTube for answer and most say it is the LED driver board problem. After that I test the voltage and accidentally short circuit the 2nd and 3rd pin.

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.

Thank you

jts1957
Veteran

Jan 29, 2017, 7:35 PM

Post #5 of 13 (7404 views)
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Re: [jackietan] TV Repair [In reply to]	Can't Post

On most TVs with this failure (Has an image on screen with flashlight - which is what is meant by: 'there is tv manual image at the dark panel'?) sound is usually present (maybe speakers are turned off in the menu).

Where as we have no way of identifying what the functions of the two pins you shorted are (pins for the connectors on the boards are not marked & I haven't been able to find schematics), introducing the current symptom (I'm assuming the symptom HAS changed), there appears to be little point in pursuing.
You should have been connecting with thinner test probe tips, if necessary, to the wire-side of connector where there is a physical barrier between pins - not the pin-side where there is no physical barrier between pins.
http://www.shopjimmy.com/...n-p1ubuu-p-board.htm - seems to be the same except part number label
http://www.shopjimmy.com/...rd-for-tc-l50em5.htm - slight difference in picture - no shield
http://www.shopjimmy.com/...82440-led-driver.htm - is the only board that has connector pin functions identified

Most words / sentence you do not understand are no longer involved as, for example, correcting links gave a pix with brand / model number.
Garbage / garage are two different things.

Will probably turn out to be one or more LEDs inside the panel. Unimpressed

Unimpressed

-------------------------
Location: Far, Far Away

(This post was edited by jts1957 on Jan 29, 2017, 11:39 PM)

jackietan
New User

Feb 1, 2017, 5:03 AM

Post #6 of 13 (7370 views)
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Re: [jts1957] TV Repair [In reply to]	Can't Post

Thank you jts1957

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

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
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Feb 1, 2017, 7:53 AM

Post #7 of 13 (7367 views)
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Re: [jackietan] TV Repair [In reply to]	Can't Post

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.

-------------------------
Location: Far, Far Away

(This post was edited by jts1957 on Feb 1, 2017, 8:20 AM)

jts1957
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Feb 1, 2017, 8:06 AM

Post #8 of 13 (7364 views)
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Re: [jackietan] TV Repair [In reply to]	Can't Post

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).

-------------------------
Location: Far, Far Away

(This post was edited by jts1957 on Feb 1, 2017, 8:07 AM)

jackietan
New User

Feb 1, 2017, 9:16 AM

Post #9 of 13 (7357 views)
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Re: [jts1957] TV Repair [In reply to]	Can't Post

Thank you very much. I took some close up photo on the rear of P2. There is F7402 and Q7403.

F7401 & F7402 do not have continuity
F7401 seem to has a 'YD' written on it
F7402 seem to has a '3321' written on it
F7101 has continuity
I do not know how to test Q7403
Power board P2 pin 1 & 2 have continuity, pin 1 & 2 does not have continuity to pin 3

I'm not professional, I do not understand some of the sentence below:

"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" What is the short for m for SJ?

I'm interested to learn more about electronic. I may not able to know much now but I can follow instruction / YouTube to try if I can repair the board.

Do you suggest buy the F7401 & F7402 to replace or change the whole board? Some also do not have continuity, are those spoilt eg. R7401, R7405, R7410, R7412, R7420..Any others I nedd to check for continuity?

Is it only after the power board is repair / replace, then can determine whether the main board is working or not, is it?

Below are the close up photos, please let me know if need more photos for reference. Thank you

Front Power Supply Board

Front Power Supply Board

Rear Power Supply Board

Rear Power Supply Board

Rear Power Supply Board

jackietan
New User

Feb 1, 2017, 9:22 AM

Post #10 of 13 (7356 views)
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Re: [jts1957] TV Repair [In reply to]	Can't Post

'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)'

'If we wind up getting this power supply back up' Is it mean 'after the power supply get repair'?

What is the meaning 'back-probe' is it mean I get a thin probe for voltage measurement in the future to avoid the incident happen again?

jts1957
Veteran

Feb 1, 2017, 11:00 AM

Post #11 of 13 (7354 views)
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Re: [jackietan] TV Repair [In reply to]	Can't Post

F7401 & F7402 are both the same value (with 'YD' written on them) fuse.
http://imgur.com/a/bncR1 Both resistance readings are to F7402 - typo in pix. Repeat the resistance tests for F7401 if it indeed is open.

Q7403 I suspect is a switch, but I can't read what is written on it. One pin would act as a 'control/enable' then multiple pins tied together would act as input & output.

'SJ' has been mentioned once by you in your initial post and in three klickable links by me ... ('Shop Jimmy.')

Also make note of a wire jumper at P2 pin 9 to ground ... that shouldn't be there.

SJ photos provide equal or better resolution than yours, but yours show the modifications that a prior 'tech' installed. You may want to post a photo of back of your main board.

Fuses you use continuity setting on Fluke. Resistors use Ohm setting.
All surface mount resistors have a three digit standard code/value stamped on them. A jumper chip may be marked with a zero. The first two digits are the value and the third a multiplier. For example a '473' would be'47' plus '3' zeros (47,000 ohms). Be aware whenever measuring resistance or semiconductor junction 'in circuit' there may be other components there that may affect your readings.

Quote

Is it only after the power board is repair / replace, then can determine whether the main board is working or not, is it?

You are the one who decided to connect ?36V? (accidentally) to ground so that may have kept damage to the Power board.

-------------------------
Location: Far, Far Away

(This post was edited by jts1957 on Feb 1, 2017, 11:20 AM)

jts1957
Veteran

Feb 1, 2017, 11:13 AM

Post #12 of 13 (7350 views)
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Re: [jackietan] TV Repair [In reply to]	Can't Post

In Reply To

'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)'

'If we wind up getting this power supply back up' Is it mean 'after the power supply get repair'? YES (or replaced)

What is the meaning 'back-probe' is it mean I get a thin probe for voltage measurement in the future to avoid the incident happen again?

Wires for each pin of a connector have a small amount of insulation stripped off so a small metal terminal can be crimped onto it. The wire with the metal terminal crimped onto it is then pushed into the plastic connector housing so that a formed metal strip can snap into plastic to prevent its removal. Usually the metal terminal can still be accessed from the back (wire side) with a small or pointy enough test probe (with or without an appropriate adaptor installed onto the test probe tip).

-------------------------
Location: Far, Far Away

jackietan
New User

Feb 2, 2017, 7:09 AM

Post #13 of 13 (7332 views)
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Re: [jts1957] TV Repair [In reply to]	Can't Post

I have make a mistake on written earlier. When my red probe accidentally touch both the 2nd and 3rd pin on the Power Supply Board, my black probe is attach to the TV metal frame.

Shall I test the voltage again?

Or will you able to advice what fuse, resister or.. to buy to replace?

Or shall I replace the Power Supply Board and LED Drive Board?

The LED Drive Board and Power Supply Board cost around $100USD in total at eBay

Main Board Front

Main Board Back

LED Driver Board Front

LED Driver Board Back

Q7403

Q7403

In Reply To

F7401 & F7402 are both the same value (with 'YD' written on them) fuse.
http://imgur.com/a/bncR1 Both resistance readings are to F7402 - typo in pix. Repeat the resistance tests for F7401 if it indeed is open.

Q7403 I suspect is a switch, but I can't read what is written on it. One pin would act as a 'control/enable' then multiple pins tied together would act as input & output.

'SJ' has been mentioned once by you in your initial post and in three klickable links by me ... ('Shop Jimmy.')

Also make note of a wire jumper at P2 pin 9 to ground ... that shouldn't be there.

SJ photos provide equal or better resolution than yours, but yours show the modifications that a prior 'tech' installed. You may want to post a photo of back of your main board.

Fuses you use continuity setting on Fluke. Resistors use Ohm setting.
All surface mount resistors have a three digit standard code/value stamped on them. A jumper chip may be marked with a zero. The first two digits are the value and the third a multiplier. For example a '473' would be'47' plus '3' zeros (47,000 ohms). Be aware whenever measuring resistance or semiconductor junction 'in circuit' there may be other components there that may affect your readings.

Quote

Is it only after the power board is repair / replace, then can determine whether the main board is working or not, is it?

You are the one who decided to connect ?36V? (accidentally) to ground so that may have kept damage to the Power board.

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