Toshiba LED TV, blank screen

[budm]

Re: Toshiba LED TV, blank screen

I cut the yellow wire #15 ( dim ) At P802 It does not works on my tv

Same model number as the OP?

[Agent24]

Re: Toshiba LED TV, blank screen

I don't know, I am not familiar with these. Just going by what the others have said.

[hienton2]

Re: Toshiba LED TV, blank screen

Hi Agent24.

My tv has dim line 3.2 v at turn on then goes to .2 v .Is this normal?
The bl on has constant 3.2.

The regulator. You mean 24v regulator of psu? Or the one on green inverter?

[Agent24]

Re: Toshiba LED TV, blank screen

Pulling wires is not a proper repair. The circuit worked before without these modifications, something has failed and modifying things will not properly fix it. Do not expect these kinds of fixes to last in any case.

In post #32 electronicsurplus mentions a voltage regulator going bad. That would be my first part to check.

[hienton2]

Re: Toshiba LED TV, blank screen

I cut the yellow wire #15 ( dim ) At P802 It does not works on my tv

[ransome]

Re: Toshiba LED TV, blank screen

I had 4 of these with the same problem , easiest way to fix is just pull out the yellow 15 wire as mentioned. fixed all 4.

[CHAD70]

Re: Toshiba LED TV, blank screen

All the parts I bought were second hand, but from "working" units...will try and look for a new PSU.

MDluffy, we never heard if you got the issue fixed on your Toshiba 46L5200U1. I am running into the same exact problem where I have sound and the Red Toshiba logo flashes on for a second then goes Black. I've tried the different "Dim" configuration mentioned above (cross 15 & 16; capping off 15; capping off 14) and have had no luck. It would be great to hear what the final diagnostic was cor your unit. Thank you!

[northwestdad]

Re: Toshiba LED TV, blank screen

The wires can be reconnected easily. They have a quick-release. Try it.

Are you talking about the wires/ribbons attached to the boards? That was the first thing I did was to disconnect, clean them off, and reconnect them. There was no change in the issue which prompted me to post in this forum.

[bktanner]

Re: Toshiba LED TV, blank screen

The wires can be reconnected easily. They have a quick-release. Try it.

[northwestdad]

Re: Toshiba LED TV, blank screen

I downloaded and installed the firmware update and the TV worked great for about an hour as my kids and I watched a couple episodes of The Simpsons. I told my wife it was fixed, she came downstairs to see and it crapped out again. Dammit.

[northwestdad]

Re: Toshiba LED TV, blank screen

Hi Folks...I picked up this same model through Craigslist last week knowing it had a very similar issue. The only difference is when turned on, i will typically get an image for a 5-10 seconds, then the screen starts flashing and goes blank. You can see the image but the backlight stops working. Audio continues to work fine. I can power the set off with the remote and immediately turn back on and the image will come back. Once in a while i can get the image to stay on for 30-40 minutes. I did a quick experiment by changing the input selection once the flashing started, and from what I could tell it did have some effect since I was able to continue seeing the menu image and the screen stopped flashing. Turning the input back to ANT/CABLE the screen would begin flashing again.

Certainly sounds like it could be a main board issue. Do you think the fix stated above would be helpful in my case? When the image stays on, the TV looks great and I'm hesitant to cut or disconnect wires that i wouldn't be able to reconnect later. Also, I hear so many horror stories of upgrading firmware I'm afraid to try it

[budm]

Re: Toshiba LED TV, blank screen

Or do the same on pin 14 ex_dim (External Dim) control signal line on that CN001 of the LED power supply board which is the same as pin 14 (DIM) of the connector P804 of the Main power supply board which is connected pin 15 of P802, the Dim control signal is just looped through the power supply board connectors.
On post 32 saying to swap the wire on pin 15 (DIM) and 16 (BL_ON: Backlights on), I do not believe that will not work because you need the BL_ON signal line to turn on the backlights circuits. The question is: Is the BL_ON or the DIM signal present or not? And is the EX_DIM PWM or Analog Dimming control signal?

[bktanner]

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.

[Towu2014]

Re: Toshiba LED TV, blank screen

I have the same issue with my unit. The wire switch doesn't change the issue. Has anyone been able to get a straight fix for this issue or am I going to have to start fishing. Thanks

[electronicsurplus]

Re: Toshiba LED TV, blank screen

In fact, this is a very common failure with a Great deal of LED Televisions

[electronicsurplus]

Re: Toshiba LED TV, blank screen

We have had many successful repairs with this model
There is a failed Voltage Regulator on the Main Board which controls dimming feature But,
This problem can be very simply be repaired by crossing wires 15 & 16 on the connector from the Power Supply to the Main Board.
The TV will not have the dimming feature but, this can easily be adjusted in the Menu by selecting Dynamic Mode or, the mode which suits your taste

Alternatively, (IF you have the proper equipment) you can change the SMD Voltage Regulator

This is a very common failure in these Televisions

This fix applies ONLY to the set initially powering on showing the Red Toshiba Logo and fade to black

Hope this Helps

Aimee
Electronic Surplus

[MDluffy]

Re: Toshiba LED TV, blank screen

All the parts I bought were second hand, but from "working" units...will try and look for a new PSU.

[Agent24]

Re: Toshiba LED TV, blank screen

Was the new PSU you bought brand new or 2nd hand? If it was brand new then probably something else in the TV is bad, if it was 2nd hand... who knows.

[MDluffy]

Re: Toshiba LED TV, blank screen

5 for 5...when TV is on, screen blank but can hear sound and use controls - pull the AC plug, wait 2 sec, plug back in (nothing else) then the TV will come back on with screen working...if I cycle power with the remote control, it screen will not turn on....

[MDluffy]

Re: Toshiba LED TV, blank screen

More than likely... I also found the setup that auto-shows in native format... seems like all the channels are now in HD and full screen... So yesterday, after an hour or so, the screen goes blank. Today, on power up it was blank (with sound and control). Cycled power twice with same result. New observation though... instead of using the remote power button, I unplugged the outlet from the wall and plugged back in... it came up fine!? Will try a few more times to see if this is a fluke or not. Thanks MDLuffy