Toshiba LED TV, blank screen

[pnlonestar]

Re: Toshiba LED TV, blank screen

I am so thankful for these posts. My solution was covered in post #32. When dealing with the wires, I found that it was easier to cut them in the middle, strip them, and then splice them together. Pulling them out seemed like more work that could possibly damage the connection.

After trying every variation possible with wire 14, 15 and 16, the solution was simply cutting wire 15 &16, then crossing them. I understand that this is a bypass fix, but it's all that I am wanting to do for now.

[hdguy]

Re: Toshiba LED TV, blank screen

SUCCESS!

I tore apart some broken earbuds for the super thin wires and fired up my solder iron, to rebuild the wire harness/connector that I broke when replacing the backlight.

With the new backlight installed, the TV is no longer flickering & dying.

Thanks everyone for your help with the repair, and the great information!
Tim

[Agent24]

Re: Toshiba LED TV, blank screen

Try eBay?

[hdguy]

Re: Toshiba LED TV, blank screen

does anybody have a spare cable ribbon from the led driver to the backlight?

I was a little too rough on the one in the tv & now I've broken the connector

[hdguy]

Re: Toshiba LED TV, blank screen

does anybody have a spare cable ribbon from the led driver to the backlight?

I was a little to rough on the one in the tv & now I've broken the connector

[hdguy]

Re: Toshiba LED TV, blank screen

UPDATE: Backlight setting @ 30 started causing problems now. I was able to make it through a 2 hr movie on 20, but considering the goal for this TV is for gaming, I decided to order a replacement LED strip.

[hdguy]

Re: Toshiba LED TV, blank screen

I have the Toshiba 46L5200U, Manufacturer Date Feb 2012.

Disconnecting DIM didn't work for me (neither the 14 pin on the power board nor the 15 pin on the control board; yes, I read that is basically the same thing, but I wanted to be sure). Not even intermittently. Having read this entire thread (and several others), pulling a pin is clearly a fix for some of the TV's - just not mine.

Since my symptom is intermittent (but easy to replicate), I was able to adjust the Backlight setting (Menu --> Picture --> Picture Settings, Backlight) to keep the TV running.

Setting Backlight to 0 (zero) kept it going all morning. Setting Backlight to 40 killed it right away. I'm now about 1.5hrs into Backlight setting at 30, and it has stayed on. The default factory setting is 70 (both before and after the firmware update, which I have applied: http://support.toshiba.com/support/m...eeText=3308679 ).

To me, this is still a temporary fix.

My hypothesis:
Remove the LCD panel and replace the Toshiba 2012SGS46 LED Light Strip Bar & it will be like new. (at which time, I would probably change my Backlight setting to 50, not 70, the default).

Any thoughts?
Feedback welcome and wanted.

[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.

[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!

[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!

[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

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

[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.

[Telefixer]

Re: Toshiba LED TV, blank screen

oops - they are 46 inch, not 40.

[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.

[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.

[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/

[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.

[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

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