Toshiba 32W1343DG No Backlights, Flashlight Test OK, TV is already broken

[eltrash]

Hello from germany, i have read many threads and have learned a lot. Now I want to open my own thread because i have an issue with my Toshiba TV.

My Problem: No backlights (The LEDs also not light shortly when power on, they shine never), but Flashlighttest was successful. So i can see the menu and messages.

The TV is already completely disassembled and I made high-res photos of all components. I hope dropbox galleries are allowed and ok:

https://www.dropbox.com/sh/ed2d3b3zr...lbrib1L3a?dl=0

Here the data of all TV-parts:
TV-Model: Toshiba 32W1343DG (32 inch)
Powerboard: VESTEL 17IPS11 300413-R4
Mainboard: 17MB95-2.1
T-Con Board Part1: 6870c c442b
T-Con Board Part2: 6870S-1578A
LED Interface: VESTEL 17DB01
LED-Stripes: VES315WNDL-01 (2 Stripes with 22 LEDs)

Apparently there is no separate LED Driver Board, because the LED strips directly are connected with a cable (red/black) to the power board. My measurements showed that in standby is close to 1.1 Volts.

At power on with the remotecontrol there are for a short time about 45 volts. The voltage is lowered slowly to 0V. It makes no difference whether the LEDs are connected or disconnected.

Here is a little video of this phenomenon: https://www.dropbox.com/s/8p4k649mn4...%2030.mov?dl=0

I would like to know, how I can find out if the power supply or the LEDs are defective.

Thank you for your help
Best regards
eltrash


P.S. Sorry for my poor English

[ReeceyBurger123]

Re: Toshiba 32W1343DG No Backlights, Flashlight Test OK, TV is already broken

Watch my video:

https://www.badcaps.net/forum/showth...t=Led+stacking

[dick_barton]

Re: Toshiba 32W1343DG No Backlights, Flashlight Test OK, TV is already broken

I don't know how similar this schematic is to your psu but check your led driver chip.

[eltrash]

Re: Toshiba 32W1343DG No Backlights, Flashlight Test OK, TV is already broken

@ReeceyBurger123, Thank you very much for your very interesting video. It seems to be the same parts like my TV

I think i made a mistake with measurement LED booster voltages. I have to measure the black and red pin individually each to ground but I have measured both pins together. I will check the voltages again soon as possible.

@dick_barton Thank you for shematics. If the voltages with the right messurement method will fail, then i will check the led driver chip.

In about 4 hours i will be @home und then i know more :-)

cu

[ReeceyBurger123]

Re: Toshiba 32W1343DG No Backlights, Flashlight Test OK, TV is already broken

No worries glad to help, videos are alot more easier to follow than complex schematics most people fine. You probably have an OC led somewhere causing the whole lot not to work hopefully you can find it

[ReeceyBurger123]

Re: Toshiba 32W1343DG No Backlights, Flashlight Test OK, TV is already broken

I don't know how similar this schematic is to your psu but check your led driver chip.

Cheers I can use them

[eltrash]

Re: Toshiba 32W1343DG No Backlights, Flashlight Test OK, TV is already broken

You probably have an OC led somewhere causing the whole lot not to work hopefully you can find it

i hope it too but i'm confident to find it or them

Can i take LEDs from this bar for replacement dead LEDs with your "Stacking method"

http://www.ebay.de/itm/Samsung-LED-T...-/322132302339

[dick_barton]

Re: Toshiba 32W1343DG No Backlights, Flashlight Test OK, TV is already broken

Cheers I can use them

I'm tending to save all the psu schematics I come across and many are saved from this forum so glad it's of use to you.

[eltrash]

Re: Toshiba 32W1343DG No Backlights, Flashlight Test OK, TV is already broken

I am afraid that i don't find a stackable LED Bar

If i choose the single LED swapping methode shown in this video https://www.youtube.com/watch?v=Bf5T2wwtydY

Which LEDs I have to choose? In the comments of the video is this one menthioned:

https://www.superbrightleds.com/more...Specifications

but the author says they are a little bit to big (5x5mm). Better are 3 millimeters x 3 millimeters. Are the other specs, like power consuption (0.192w) ok?

[ReeceyBurger123]

Re: Toshiba 32W1343DG No Backlights, Flashlight Test OK, TV is already broken

You can use 3v 0.5w pure white Smt Leds for the job buddy. Or if theres only one bad just bridge over it woth solder or use a resistor, they are dropping like flies so if you want something quick just do that.

[eltrash]

Re: Toshiba 32W1343DG No Backlights, Flashlight Test OK, TV is already broken

thanks my friend.

I have great news, the voltages of the power supply are fine. After power on the TV the LED Output boosts to about 102 volts and than it drops to 22 volts.
This should be fine, right?

Then I have identified the bad LEDs with my multimeter and your great messure method. All exept one per row are glimming. One has open circuit, the other one has short circuit.

I bridged the open LED and see what happend...



Yeah, it works

Now i have to decide if i replace the bad LEDs or bridge them easily.
If i would bridge, i should insert a resistor because otherwise the working LEDs Overload, right? If so, what resistors i should choose?

EDIT: Other idea... can i instead of inserting a resistor reduce backlight parameter via TV-Settings to a very low value?

Thanks for your great help so far, I'm excited :-)

[ReeceyBurger123]

Re: Toshiba 32W1343DG No Backlights, Flashlight Test OK, TV is already broken

You could use a 22ohm one watt resistor to sub them mate. Also good work

[eltrash]

Re: Toshiba 32W1343DG No Backlights, Flashlight Test OK, TV is already broken

ok, thank you for your help. The resistor solution is my backup strategy.
At first i want to order some fitiing LEDs but i don't find such 0,5w high power LEDs with only 3x3mm dimension. If i calculate correct they should have amperage of 150 mA.

I only find 0,2W (60 mA) smd plcc2 2835 LEDs with dimensions: 3,5 x 2,8mm

Can you give me short advise how i can find correct LEDs?

[budm]

Re: Toshiba 32W1343DG No Backlights, Flashlight Test OK, TV is already broken

You need to find out if the big pad is ANODE or CATHODE on your board.
Large pad is ANODE
http://fr.aliexpress.com/item/100PCS...d-568b936e832f

Large pad is CATHODE
http://fr.aliexpress.com/item/SAMSUN...08.8.48.ZgPJcJ

[eltrash]

Re: Toshiba 32W1343DG No Backlights, Flashlight Test OK, TV is already broken



sorry for the stupid question: Are there more than 2 solder pads per LED?

EDIT: Oh, there is a big and a small pad, i understand :-) therefore it is important to pay attention to the identical LED layout

[ReeceyBurger123]

Re: Toshiba 32W1343DG No Backlights, Flashlight Test OK, TV is already broken

sorry for the stupid question: Are there more than 2 solder pads per LED?

EDIT: Oh, there is a big and a small pad, i understand :-) therefore it is important to pay attention to the identical LED layout

You have it labeled correctly, if you usolder the led large pad is positive and smaller is negative.

[eltrash]

Re: Toshiba 32W1343DG No Backlights, Flashlight Test OK, TV is already broken

ok, thank you for confirmation but i cannot wait 60 days for delivery. In germany those LEDs are not available, only as complete stripe arrays for Stacking method
But this are not the same LEDs like in my TV. Is it a problem if i would buy this for example?

http://www.ebay.de/itm/Samsung-LED-T...z/322132302339

Sorry for my many questions
thank you for your patience
lg eltrash

[ReeceyBurger123]

Re: Toshiba 32W1343DG No Backlights, Flashlight Test OK, TV is already broken

Yes you can use any Led strips to sub them with stacking method. Also its not Lg its Vestel built with an Lg screen. The Lg part is ok the rest is crap.

[eltrash]

Re: Toshiba 32W1343DG No Backlights, Flashlight Test OK, TV is already broken

Hello, good news. The repair was successful with the stacking method.

The TV works wonderful. The illumination is very even, there are no spots although there are LEDs of a different model. Color temperature and luminosity are identical

Thanks again for your help, especially on ReeceyBurger123

[dick_barton]

Re: Toshiba 32W1343DG No Backlights, Flashlight Test OK, TV is already broken

Well done. Another set saved from the trash.