Toshiba LED TV, blank screen

[vinceroger69]

Re: Toshiba LED TV, blank screen

It maybe better if you start a new thread for your tv please include the model number and some good clear pictures of the boards used in your set.

[vesterlee2008]

Re: Toshiba LED TV, blank screen

I own a TOSHIBA 46L5200U1, I replaced the power board and now the red Toshiba comes on. There was still no picture when I hooked up my bluray player. I actually read through some previous threads and removed the yellow wire. BOOM just like that it is now working. There is a slight dis-coloration on the left side but hardly noticeable. I would still like to know what else could be a fix because I am sure the yellow wire needs to be connected.....

[D-Einsight]

Re: Toshiba LED TV, blank screen

I'm like everyone else .... Toshiba 46L5200U1 1-1/2 yrs old , black screen .This is some WONDERFUL information Guys !!!!! I'm going to give it a try tonight !!!! D-E

[simondumais1]

Re: Toshiba LED TV, blank screen

Could these LED fit these strips?

Cree XLamp ML-C

I have a 46L5200 that is flashing the toshiba logo. I have to test for the led arrays, but i would like to fix it properly by replacing a LED if it is a LED that is broken. I've watched the videos that Norcal715 did on this exact same problem but he did install a Zener in place of the LED.

What you guys think?

[the8re]

Re: Toshiba LED TV, blank screen

Howdy all. Found this forum as I had a 46L5200U1 with this very same issue. Opened it up, pulled wire 15, put it back together, and I'm good as gold. Thank you all so much!

Even updated the firmware while I was at it.

Additional info: The TV came with the house when we bought it. The sticker on the back says September 2012.

Again... thank you all for keeping the peace in my house!

-t

[googlefu]

Re: Toshiba LED TV, blank screen

So I really hoped this would work for mine. I just got this TV used on CL. I hooked it up as a second monitor to my computer and the first night it worked beautifully. I fell asleep watching Star Wars and life was beautiful. The next morning it was dark, I assumed it had gone to sleep. But it never woke up.

So here's what it does. I plug it in, push power, the light comes on and the screen backlight comes on with nothing but gray until the Red Toshiba logo comes on for a split second and then the screen goes dark but the light is still on. Unplug and try it again. Same. and again. and again.

Then I came here and read the comments and tried pulling plug 15. No dice. So it pulled the yellow wire on the other side too. Same thing.

I tried moving the wire bundle from P804 to P803. No change. I also pulled out wire 14 marked Ex_dim and then tried it again on the other side of the bundle. No change. I always get a flash of the toshiba logo and then nothing. Any ideas?

[tpod77]

Re: Toshiba LED TV, blank screen

Hello all. I've been reading this thread for about a year. I picked up a Toshiba 46L5200U1 from work. My employer purchased it to use as a display for a Rolex ad running on repeat ad nauseum (I'm a jeweler at a high-end jewelry store). It burned out after 18 months. The Toshiba logo appeared in red after powering on and then it went dark with the image visible only when viewed with a flashlight. I found this thread after a quick Google search and tried pulling the #15 DIM wire. I felt a great sense of accomplishment but it went away after five minutes when the screen went dark again. The TV went into the basement and after a year my fiancee said the TV needed to be fixed or it was going to the dump. I bought a new LED driver board, reconnected the #15 wire, and voila, it worked again. For two weeks. I'm at a loss. I've read the entire thread. Should I take another crack at it? The resistor solution sounds promising but I don't have a whole lot of experience with DC circuits.

[tpod77]

Re: Toshiba LED TV, blank screen

The analog dimming (not used by TOSHIBA, the TV uses the PWM dimming) has pull -up to full 5V for max backlights level, so I use the resistor (between analog dim and gnd) to drop the Analog dimming line down to about 3.5VDC or so. When PWM wire is disconnected, the ANALOG dim becomes active so you can vary the backlights by varying the ANALOG diming Voltage.
If the PWM line stuck low, then it will force of the backlights off. If you monitor the PWM line and see <1V then the PWM line is not working.
The one shown in the pictures, when you first turn ont he TV, the PWM line show around 4V (it is actually AC 200 Hz PWM, 0~5V pulse, 10% pulse width = min brightness, 90% pulse width = max brightness) which you will see the screen flashes on for second then the PWN drops down to 0V which then the baclikghts go out, in my case I have two problem, one is the PWM signal and anther one are bad LEDs strip that goes out if they driven full on.

Hey, Bud. I'd like to try your resistor solution. Could you walk me through it? I've checked out the pics you posted to photo bucket but I don't see exactly where you added the resistor. I'd really appreciate any advice you can give me. As you can see from my most recent post, I've put too much work into this project to just give up.
Thanks
Tristan

[Nick's Tvs]

Re: Toshiba LED TV, blank screen

If you have never replaced an LED before or have trouble with the replacement

http://www.ebay.com/itm/Repair-Servi...sAAOSwBnVW8qwT

[tpod77]

Re: Toshiba LED TV, blank screen

Okay. I soldered a 220 kohm resistor from pin 13 to ground. Powered it on, got the Toshiba logo, "no signal" screen, went to menu just before it blacked out. Here's a picture of the resistor soldered to the board, the replacement I bought from China. I'm also posting a picture of the original board next to the replacement so you can see how different they are. It worked great for a couple weeks, though. It's worth noting that when I plugged it in after adding the resistor the plug sparked when I pushed it into the outlet. I'm beginning to think the resistor was too low a wattage. I have no clue what I'm doing.

[CAS1234]

Re: Toshiba LED TV, blank screen

Okay. I soldered a 220 kohm resistor from pin 13 to ground. Powered it on, got the Toshiba logo, "no signal" screen, went to menu just before it blacked out. Here's a picture of the resistor soldered to the board, the replacement I bought from China. I'm also posting a picture of the original board next to the replacement so you can see how different they are. It worked great for a couple weeks, though. It's worth noting that when I plugged it in after adding the resistor the plug sparked when I pushed it into the outlet. I'm beginning to think the resistor was too low a wattage. I have no clue what I'm doing.

I stumbled on this and I know the answer, Bad capacitors. I had the same problem with a monitor. There is a way to repair the LCD. A company in Taiwan copied a Japanese formula for capacitors but got it wrong and as a result the caps fail. I was looking for Black Friday deals on LCD TV's and found a Toshiba 49L621U 49-in selling for $199 at Best Buy. However I could not find any customer reviews. Even Consumer Reports liked it but I smelled a rat without independent customer reviews. So I looked up Toshiba problems and found you guys but I've been here before and became a member. Now that I've found the Black Friday rat I am satisfied. There is even a write up on this on Wiki, but that is a bookmark search and I'd rather watch NFL football now. You will have to repair it yourself after ordering the caps and the kit. Anyway here is the link to the capacitor problem that might help you repair what is probably now a paper weight:
http://www.ccl-la.com/blog/index.php...ouse-lcm-22w3/

[Alastair E]

Re: Toshiba LED TV, blank screen

I stumbled on this and I know the answer, Bad capacitors. I had the same problem with a monitor. There is a way to repair the LCD. A company in Taiwan copied a Japanese formula for capacitors but got it wrong and as a result the caps fail. I was looking for Black Friday deals on LCD TV's and found a Toshiba 49L621U 49-in selling for $199 at Best Buy. However I could not find any customer reviews. Even Consumer Reports liked it but I smelled a rat without independent customer reviews. So I looked up Toshiba problems and found you guys but I've been here before and became a member. Now that I've found the Black Friday rat I am satisfied. There is even a write up on this on Wiki, but that is a bookmark search and I'd rather watch NFL football now. You will have to repair it yourself after ordering the caps and the kit. Anyway here is the link to the capacitor problem that might help you repair what is probably now a paper weight:
http://www.ccl-la.com/blog/index.php...ouse-lcm-22w3/

What on EARTH are you on about!

You post a link--to a Completely DIFFERENT DEVICE (Comp-Monitor)--Not even the same Make for gods sake!

Not Everything is Caps, But as you make quite plain--You Dont Know That, you're repeating parrot-fashion ancient history!!

Best stay away from repairs and watch the match is my advice.

[Telefixer]

Re: Toshiba LED TV, blank screen

Yep, that was interesting reading! I have a couple of 40 inch Toshiba HL900 sets, with the Logo appearing VERY briefly, and then no backlight but the display still working in the dark. Did some testing on the driver board, not convinced it was faulty. Backlight LEDS appeared okay. Also a Toshiba agent, however info is sparse. I then found these threads, and disconnected pin14 of the LED driver board, it's a 14 pin plug, and hello both sets work faultlessly. Yes, there should be a reason the device driving the ext dim line isn't working, but considering the value of the set, it becomes a question of economics of how much time one spends on it.

[Telefixer]

Re: Toshiba LED TV, blank screen

oops - they are 46 inch, not 40.

[kuhurdler]

Re: Toshiba LED TV, blank screen

I discovered how to disable the detection circuit that turns off the LEDs here: http://www.riddledtv.com/forums/tosh...ard-t3541.html
Obviously this is for troubleshooting purposes only.

[jstiene]

Re: Toshiba LED TV, blank screen

Hello.

I have (2) of the Toshiba 46L5200U models both with the common problem described in this thread. Turn on logo shows up...screen flickers and then blanks out. Was a final solution ever determined? It seems disconnect of yellow wire 15 works for some and not others. Is the real issue a bad LED bulb or the main board circuitry. Just wanted to restart this conversation to see the latest thoughts before I start to work on these..thanks!

Joe

[Agent24]

Re: Toshiba LED TV, blank screen

It seems nobody bothered to figure it out, because it was easier to disconnect the wire.
I haven't re-read the thread, but from the name "ext dim" it seems to be dimming input signal to the inverter?

What does the inverter expect? What signal is being fed in? Perhaps the power and signal sequencing has gone wrong.

Getting a waveform of the inverter control signals with a logic analyser from a working set and comparing them to a non-working one may help narrow down where the problem lies?

[jstiene]

Re: Toshiba LED TV, blank screen

I am ok with disconnecting the wire if that fixes the problem, but I could not seem to determine from reading the thread, with all the comments, if that is actually a long term fix. There seems to be some comments that there is a shorted/bad LED as the cause to the problem.

Does anyone have any updates on this quick fix?

Thanks!

[jstiene]

Re: Toshiba LED TV, blank screen

Quick question to those familiar with this issue. I disconnected the Yellow Wire..#15..and the screen blanks out after a few seconds..with the initial flashing first...did I do something wrong or is this telling me there is a shorted LED really causing the screen shutdown?..

Any help would be appreciated...
Thanks!

[Agent24]

Re: Toshiba LED TV, blank screen

You probably have some other fault with the same symptom. Reconnect the wire and start troubleshooting the backlights normally.