Toshiba LED TV, blank screen

[Louis82]

Re: Toshiba LED TV, blank screen

Hi budm. My tv without making any modification (disconnecting yellow wire or adding a resistor) already measures 3.5v on pin 13 LED driver board. Is that normal? In post #82 you mention that it measure 5v full backlight power and that you add a resistor to lower it down to 3.5v.

I tried what you guys been doing here, disconnected yellow wire pin 15 and I added a 200kohm resistor and power goes down to 2.2v and the screen flashes and goes black. I added another resistor 280kohms 2.8v and same thing. Any input?

Thank you

[tibimakai]

Re: Toshiba LED TV, blank screen

Mine shows 3.5V as well, at maximum brightness. With a resistor, I have dropped it at 2.8V.

[Louis82]

Re: Toshiba LED TV, blank screen

Yeah I did that. Lowered down to 2.8v and screen flashes in less than a minute.

[tibimakai]

Re: Toshiba LED TV, blank screen

My TV, it was running OK for hours at a time, so yours may be in worse shape, then mine.
Bud should chip in.

[budm]

Re: Toshiba LED TV, blank screen

Hi budm. My tv without making any modification (disconnecting yellow wire or adding a resistor) already measures 3.5v on pin 13 LED driver board. Is that normal? In post #82 you mention that it measure 5v full backlight power and that you add a resistor to lower it down to 3.5v.

I tried what you guys been doing here, disconnected yellow wire pin 15 and I added a 200kohm resistor and power goes down to 2.2v and the screen flashes and goes black. I added another resistor 280kohms 2.8v and same thing. Any input?

Thank you

But do the backlights stay on without any resistor, if not, then your LEDs are too far gone.

[Louis82]

Re: Toshiba LED TV, blank screen

Tv stays on for like 2-3 hours without any resistor or modification, then it blacks out.

Last night I went in to the customer menu and lowered down the backlight setting from 100 to 30 and stayed on all night. This morning I thought I could probably bump it up to 50 but it started flashing again so I left it on 30 and is playing fine.

Would you say that my LED's are extremely bad ?

[budm]

Re: Toshiba LED TV, blank screen

Tv stays on for like 2-3 hours without any resistor or modification, then it blacks out.

Last night I went in to the customer menu and lowered down the backlight setting from 100 to 30 and stayed on all night. This morning I thought I could probably bump it up to 50 but it started flashing again so I left it on 30 and is playing fine.

Would you say that my LED's are extremely bad ?

Yes, they are in real bad shape. If if it cannot work at 50% then you have to change the LEDs or live with less backlights until it dies. Also tell the customer when they get new TV to lower the backlights level down as low as possible to extend the life of the LEDs. It does not look like no matter what brands of TV you buy, they all seem to have bad LEDs problems.

[tom66]

Re: Toshiba LED TV, blank screen

I have noticed this failure mode with LEDs before. I have had several 230V "GU-10" LEDs fail, these are small ones you get in kitchens etc. Normally 35-50W halogen but replaced with LED to save energy.

Usually they begin to flicker and pulsate before they go out for good. Always just one LED that dies in a chain of about 50 or so. Seems it might be a failure of the bond wires as it's some kind of thermostatic effect.

[tibimakai]

Re: Toshiba LED TV, blank screen

You should take the screen apart and see, which one causes the problem.

[Treydogg77]

Re: Toshiba LED TV, blank screen Question For "Bud"!

Bud,

Where can a man find LEDs for this unit other than Fleabay? If anyone else has a line on these led or led strips feel free to chime in!

Thank you,

T-Dub

[Treydogg77]

Re: Toshiba LED TV, blank screen, LED Replacement

Okay I finally took the TV apart to see how many LED were out and it was one! What's the easiest way to remove one of these LEDs? I have a light strip from another TV that I can use to replace the LED. I am having trouble removing the led without damaging it. Check the pictures

[Agent24]

Re: Toshiba LED TV, blank screen

That's what hot air rework tools are for.

You may also be able to do it with a heat gun on low from the bottom side of the board.

[budm]

Re: Toshiba LED TV, blank screen

BTW, the LEDs in that Video are Dual-LED (two LEDs connected in series inside one package) that is why the Vf is so high.

[Sierra9093]

Re: Toshiba LED TV, blank screen

tibimakai, if you could find the time, could you post a picture of your repair regarding the resistors. I have unplugged the #15 wire and now my set is working. But i would like to add the resistors if that will help the fix stay fixed longer.

[tibimakai]

Re: Toshiba LED TV, blank screen

That TV is sold already.
All the info that I have, is in the thread.

[budm]

Re: Toshiba LED TV, blank screen

tibimakai, if you could find the time, could you post a picture of your repair regarding the resistors. I have unplugged the #15 wire and now my set is working. But i would like to add the resistors if that will help the fix stay fixed longer.

Read post 88 on up to see what we have done.

[Sierra9093]

Re: Toshiba LED TV, blank screen

The above info was nearly correct. Pull the #15 wire and tape it off. (You can read the board code that says "dim".) Viola! I just figured this out today, and multiple tests show success.

Did this and it seemed to work, but for how long. Other post say this may bring other issues, like heating and such. There is a work around by placing a resistor from "pin 13" to ground. My question is what "pin 13", there are a couple on the board. A Pic of the work around would help.

[Sierra9093]

Re: Toshiba LED TV, blank screen

Hi, pulled wire on pin 15, and it worked. I would like to put the resistor workaround for the heat problem. I wish you would post a picture or a diagram of the resistor fix. Thanks in advance.

[budm]

Re: Toshiba LED TV, blank screen

Did this and it seemed to work, but for how long. Other post say this may bring other issues, like heating and such. There is a work around by placing a resistor from "pin 13" to ground. My question is what "pin 13", there are a couple on the board. A Pic of the work around would help.

LED driver board pin 13. look at the pictures in post 88, and read the rest of the threads.

[vesterlee2008]

Re: Toshiba LED TV, blank screen

I have the same issue, I have no back light or any kind of lights coming on my tv. I cant even see the Toshiba logo unless I shine a flash light on it. I have sound but no picture unless I shine a flash light on it. Any help is needed. I have read every thread and not one them helped with my issue.