Toshiba LcD TV 40L1333b sound no picture

[homer10]

hello This is my first post, My Toshiba 40L1333b LED TV has sound but no picture. I used a torch in the dark and the picture is barely visible. and we have sound any help would be appreciated thanks in advance

[CapLeaker]

Re: Toshiba LcD TV 40L1333b sound no picture

So... no backlight you say... Does the backlight come on for a second when you turn the TV on? We need good pictures of the boards.

[homer10]

Re: Toshiba LcD TV 40L1333b sound no picture

hi no flicker at all the board number is 17pw07-2

[selldoor]

Re: Toshiba LcD TV 40L1333b sound no picture

Pictures are not really good enough for troubleshooting - need better lighting - daylight no flash. Power supply is a Vestel which is a can of worms. There should be another board
or two? One distributes power to the LED back light the other is the main board that
controls everything - again if it is a vestel main the word control may not apply.

[homer10]

Re: Toshiba LcD TV 40L1333b sound no picture

control board

[homer10]

Re: Toshiba LcD TV 40L1333b sound no picture

power board

[Herbssat]

Re: Toshiba LcD TV 40L1333b sound no picture

Is your panel a samsung lta400hm23?

[budm]

Re: Toshiba LcD TV 40L1333b sound no picture

OK, what DC Voltage do you have on the two legs of the main filter caps (47uF 450VDC) and on the two legs of the filter caps (1000uF 35V) of the LED driver circuit?

[CapLeaker]

Re: Toshiba LcD TV 40L1333b sound no picture

sounds like the PFC is fubar.

[homer10]

Re: Toshiba LcD TV 40L1333b sound no picture

(47uF 450VDC) is 394v and (1000uF 35V) 24.3v

[budm]

Re: Toshiba LcD TV 40L1333b sound no picture

OK, PFC Voltage booster is working, and the 24V LED power supply is OK.
Can I see the whole back side of the TV so I can see how all the boards are connected together?

[homer10]

Re: Toshiba LcD TV 40L1333b sound no picture

here you go there is one more board but its a git to get at

[budm]

Re: Toshiba LcD TV 40L1333b sound no picture

OK, one board I do not see is the LED driver board, it may be inside the LCD panel.
I found the SCH for the power supply board from TOM66 web site.
You can check connector PL306 to see if the BL_ON/OFF signal is present or not, if it is present, then you will have to locate that LED driver board, we know that we do have 24V to feed the LED driver board, that 24V is boosted to higher Voltage to drive the LED strings.
If the LED driver board is inside the panel, that will be a big job to get to it.

[homer10]

Re: Toshiba LcD TV 40L1333b sound no picture

how do i check connector PL306 to see if the BL_ON/OFF signal is present or not im new to this dont know much

[budm]

Re: Toshiba LcD TV 40L1333b sound no picture

Turn the TV on, set your meter to DCV, black probe on the chassis, red probe on the pin of the connectors that I redlined.

[homer10]

Re: Toshiba LcD TV 40L1333b sound no picture

that says 3.24v thanks

[budm]

Re: Toshiba LcD TV 40L1333b sound no picture

OK, the main board is sending the correct signal, so it is the matter of finding that LED driver board.

[homer10]

Re: Toshiba LcD TV 40L1333b sound no picture

ill get that out in the morning you have been a great help thanks alot

[budm]

Re: Toshiba LcD TV 40L1333b sound no picture

This is may be your LED driver board:
http://www.ebay.co.uk/itm/like/26155...ectorid=229508

[homer10]

Re: Toshiba LcD TV 40L1333b sound no picture

no thats not it ive had it out once