Toshiba 40L3433DG blinking red/green power indicator

[Terrotiste]

Hello
I just got back from my parents' TV which is a Toshiba 40L3433DG.
When I plug it on the 220 v, the LED on the front of the TV flashes from red to green without stopping.
When I turn on the TV via the buttons behind the TV, the led turns green but no picture.
After seeing many post about the problems Vestel, do you think that the problem comes from the firmware that I must reflash via Usb, or is a power failure or leds hs in the backlighting?
Thanks for your help
Best regards
Jérôme

[yohnsee]

Re: Toshiba 40L3433DG blinking red/green power indicator

Hi Jerome,
could you provide us some quality photos from the pcbs? For this, you need to take down the back panel. Also, you will find a sticker on the back of the display panel, please write that down also.

Edit: First, you can make a simpler test. Get a flashlight, or turn on the one on your smartphone, and when the green light comes on, press a menu button on the remote or the side panel. Point the flashlight towards the display from a distance about 2-3cm, and search for a dim image of the menu. If it shows up, then the problem is with the backlight section of your Tv.

[Terrotiste]

Re: Toshiba 40L3433DG blinking red/green power indicator

Hello
First of all thank you for your reply
I reconnected the tv this morning, and it flashed red green then went green alone. Not against any image, even with a video entry on the HMD1.
With the torch of my camera as described by you no picture.
By cons what I noticed is that when the TV is on, we hear a loud whistling noise coming from behind that varies in intensity ... and that stops when I put it to sleep ...

Not having the remote control I started it with the buttons of the pannel back ...

I tried with a Toshiba 32w1333DG remote control, but no reaction, maybe not the same

I'm going to open the back cover tonight and I'll give you the PCB references ...

A track on this bizzare and continuous whistle that I think is not normal?

thanks a lot for your help

Best regards
Jerome

[yohnsee]

Re: Toshiba 40L3433DG blinking red/green power indicator

Now we have to focus on one problem at a time. You don't have a remote, that is not a problem. Everything we need can be done on the panel. At this time, I can't say anything about the noise. We will see that later. One more thing, that we didn't discussed yet: when the green light comes on, does the backlight do anything? I mean, does it come on for even a second, or the display is the same dark as in standby mode?

[Terrotiste]

Re: Toshiba 40L3433DG blinking red/green power indicator

Hello

Not anything at all, when the indicator goes green, there is not even a quarter of a second or the screen turns on ... desperately black.
I opened the TV and I attach some photos

Thank you again for your help

Jerome

[yohnsee]

Re: Toshiba 40L3433DG blinking red/green power indicator

Ok, now you will need a multimeter to measure voltages, and a lot of patience. And I shouldn't mention, but be very careful, as the upcoming measures will be with the power turned on, so don't touch anything on the mains side.
First, please measure the DC voltage between the 2 legs of one capacitor, seen on your 3. photo (Elite, 47uF, 450V) I write it because I can't see the position numbers. Once again, be very careful, this should be around 390-400V DC.
Please take a measurement in standby, and also in switched on state.
After this, put the negative (black) probe of your multimeter on the metal plate of the display. With the red one, measure the pins that are connected with a cable between the power supply and the main board. Also do this twice, once in standby, once powered on.
Write down here please the results.

[Terrotiste]

Re: Toshiba 40L3433DG blinking red/green power indicator

Hello
Thank you for your help . I just discovered that the transistor Q301 is short ciruit between these two outer tabs, control welded and unsoldered.
The current transistor in place is a FQPF7N80C whereas on the diagram shows that it is normally a FQPF8N60C ..
The platinum is a 17IPS20
What should I do, back a new with the same reference or the one shown on the diagram that may not be my tv
thank you for your help
cordially
Jérôme

[yohnsee]

Re: Toshiba 40L3433DG blinking red/green power indicator

If you repair a few Vestel pcbs, you will see that a lot of thing are different on their schematic and on their real boards.
Schematic has FQPF8N60C, that is a 600V 7.5A FET, while FQPF7N80C is a 800V 6.6A one. Both suits the job, I think factory went with 7N80C because it was cheaper. Or has greater safety margin in voltage.
Anyway, if you already soldered it out, and it tested short this way, then you should change it. But you should test first, if no other components went also wrong. Also, if you have an oscilloscope, you can probe the output of the SMPS chip, if it gives a good pwm signal to control the FET.
On the schematic, there is a relay. Is it also on your PCB? Does it click? Or did it click, before desoldering this FET?

[Terrotiste]

Re: Toshiba 40L3433DG blinking red/green power indicator

Good evening
After watching the power board, I see no relay ... What number should it have so I look for its position on the PCB ....
I have no more osciloscope has made almost no more electronics for many years. Visually I controlled the components of the power supply, then with my mutimeter, I found nothing alerting ... but that does not mean that other components are not HS. I ordered the transistor on Ebay in England, I just have to wait until it arrived at my place to put it in place ... and crossed my fingers ..

Other tracks to explore?

thank you for your help
Best regards
Jerome

PS: I watched other power supply of the same model on the internet and none has the printed circuit brown around the transistor like me. Like what he has to heat up. See the picture I sent you during a message

[yohnsee]

Re: Toshiba 40L3433DG blinking red/green power indicator

If you didn't find any alerting signs or measurements, you can't do anything else, than wait.
Change the FET when it arrives, then double check everything. Make sure, there is no short circuit to ground from any of the power lines. Then cross your fingers and plug it in

[Terrotiste]

Re: Toshiba 40L3433DG blinking red/green power indicator

Hello
Sorry for my delay for my answer but I was traveling so not too much time to take care of the TV. Nonetheless, I changed the transistor on the power supply and the TV refitted.
After a week of use, I heard a loud noise in the TV and it went off completely
I redemitted the power supply and I contasted that the integrated circuit CMS located near the transistor changed side welding to explode ...
Not having the capacity to change a CMS integrated circuit, I bought a 17IPS20 060913R6 power card having the same references on the internet but comparing the 2 cards I see some differences notament around the transitor that I changed on the old map. On the old diode that does not exist on the new, by cons a self more on the new map.
The new map back, the tv does not start, no image neither sound nor retro eclairge. The LED on the front panel flashes on startup in green then red slowly, then after a few seconds, the red green flashing is faster ....

A trail to explore?

thank you very much

Good night
Jerome

[yohnsee]

Re: Toshiba 40L3433DG blinking red/green power indicator

Hello,
can you post clear pictures of the new board? I am interested in the connection headers. Maybe the problem lies there. But also take it into the list, that maybe the defective power supply has damaged the mainboard.

[Terrotiste]

Re: Toshiba 40L3433DG blinking red/green power indicator

Good evening
Find attached photos of the old TV power ... the first 4 photos ... the next 6 correspond to the new food purchased on the internet. You will see that both cards are 17ips20 060913R6, but the barcode labels stuck on the cards are different. You will also see that the components around the transitor changed are different (one less diode and one self more)
When turning on the tv the voltage on the connector feeding the leds is 116 v, then fall after a few seconds ... test realized by having disconnected the connection cable between the motherboard and the tcon ...
thank you for your help
cordially
Jerome

[yohnsee]

Re: Toshiba 40L3433DG blinking red/green power indicator

Hello,
then you need to test the power board first. Disconnect the main board from it, but keep the backlight connected. Now be very careful, you need to measure the voltages. First, find the standby voltage. Should be 5V, and it must be there, regardless the set is off. If it is OK, then grab 2 resistors, 100-1000 ohm is ok, value is not critical. Now, connect one leg of resistor to standby voltage, the other to Pin3 of the black connector. Now you started the power board without mainboard. Now measure, do you have 12V on the connector pin10, 11 or 12.
If yes, then only one more step on this testing. Grab the other resistor, connect one of its legs to 5V like before, the other leg to pin5 on connector. This should light up the backlight LEDs. If so, then your power supply is OK, you will have problem(s) on the mainboard.

[Terrotiste]

Re: Toshiba 40L3433DG blinking red/green power indicator

Hello

Thanks for your help...

But where can i find the 5V ? on the black connector?

Thank

Best Regard

Jerome

[yohnsee]

Re: Toshiba 40L3433DG blinking red/green power indicator

Hello

Thanks for your help...

But where can i find the 5V ? on the black connector?

Thank

Best Regard

Jerome

Yes, every pin number I wrote is for the black connector.

[Terrotiste]

Re: Toshiba 40L3433DG blinking red/green power indicator

Good evening
Sorry for the delay of the tests but much to do at work ..

Following your advice, tablecloth between the power supply and the motherboard, I can not find the 5V stby on pin 9. On the other hand I find a 12 v on pins 10 11 12 ... without using any resistance,

Is this normal? the 5v stby seems to be generated by the 12 v through a transistor Q212, from the scheme I found on the net, but no luck this transitor is not mounted on my power card

thank you for your help

Jerome

[ducky29]

Re: Toshiba 40L3433DG blinking red/green power indicator

Flash the firmware. If that dosen't work, then replace main board.

[yohnsee]

Re: Toshiba 40L3433DG blinking red/green power indicator

Good evening
Sorry for the delay of the tests but much to do at work ..

Following your advice, tablecloth between the power supply and the motherboard, I can not find the 5V stby on pin 9. On the other hand I find a 12 v on pins 10 11 12 ... without using any resistance,

Is this normal? the 5v stby seems to be generated by the 12 v through a transistor Q212, from the scheme I found on the net, but no luck this transitor is not mounted on my power card

thank you for your help

Jerome

So, just to sum up, what happened until now:
TV was not turning on
You found a shorted FET on the power board
You changed this FET, and the set was working for a week
Then it went wrong again
You replaced the power supply board, but it is not the correct model
Now it doesn't start, and we are looking for the differences.

I just summarise the steps, please confirm I got it right. Then I search for a compatible service manual for this power board, and find out, if it can be used with your mainboard without too much trouble.

ducky29: If I got it right, his TV worked for a week when he repaired the power supply for the first time, so I don't think his problem is software related (yet)

[Terrotiste]

Re: Toshiba 40L3433DG blinking red/green power indicator

Good evening
You have exactly summarized the situation ....
Tv with mosfet curcuit, mosfet change, TV ok for a week, then power supply ko, integrated circuit exploded, change the power supply card by a similar, which is not strictly identical, the tv flashes green / red slowly, then faster indefinitely ...
According to the advice of the site, downloading the firmware on the site of toshiba, 2 files on a Usb key in fat or fat 32 and no 3 , mb90_en.bin & usb_auto_update_A1.txt , no mboot.bin....., insertion on the port of the motherboard, no detection of the key ... By cons' have observed the following thing. If I start the TV with the Ok key pressed, the TV does not blink and turns on red led on .... if attempt to start with the remote control, then the led starts flashing red green ... Some light noises in the power supply when the tv tries to start ....

A track to help me? problem of the power card that is not exactly identical or falsh concerns?
In any case I have not found 5v present on the power supply card but just the 12V

Thanks for your help
Best regards
Jerome