TOSHIBA 39L4333D, powers on, no standby, backlight on, won't shut down

[budm]

Re: TOSHIBA 39L4333D, powers on, no standby, backlight on, won't shut down

So you get the backlights to be on, but do you now see images on the screen?

[Sraros]

Re: TOSHIBA 39L4333D, powers on, no standby, backlight on, won't shut down

MM voltage tests in BL connector at power supply:
VF1:84,4
VF2:84,4
VF3:52,9
VF4:52,9
FB1:52,9
FB2:52,9
FB3:21,5
FB4:21,5

[Sraros]

Re: TOSHIBA 39L4333D, powers on, no standby, backlight on, won't shut down

So you get the backlights to be on, but do you now see images on the screen?

Nope still nothing, neither with a flashlight test

[dskall]

Re: TOSHIBA 39L4333D, powers on, no standby, backlight on, won't shut down

I'm confused. Are your backlights working?

[vinceroger69]

Re: TOSHIBA 39L4333D, powers on, no standby, backlight on, won't shut down

reading this thread again from post 16 it seems you have lost the backlight and the toshiba logo after re loading the firmware are you 100% sure its the correct firmware for the mainboard and lcd panel used in your tv.

[Sraros]

Re: TOSHIBA 39L4333D, powers on, no standby, backlight on, won't shut down

My backlights are working I just don't have any kind of picture. I notice that the brightness of the LEDs changes if I press for example the menu button or the tv program switches from dark to vivid images but that's all

[Sraros]

Re: TOSHIBA 39L4333D, powers on, no standby, backlight on, won't shut down

reading this thread again from post 16 it seems you have lost the backlight and the toshiba logo after re loading the firmware are you 100% sure its the correct firmware for the mainboard and lcd panel used in your tv.

Nono the logo I lost a lot far back before the firmware update. Back then when I was searching for problems in the power board. I just didn't care so much since the TV wasn't working either way.

[vinceroger69]

Re: TOSHIBA 39L4333D, powers on, no standby, backlight on, won't shut down

have you checked the voltage on both sides of the tcon fuse?

[budm]

Re: TOSHIBA 39L4333D, powers on, no standby, backlight on, won't shut down

My backlights are working I just don't have any kind of picture. I notice that the brightness of the LEDs changes if I press for example the menu button or the tv program switches from dark to vivid images but that's all

Are you saying you can see the ON SCREEN SETTING MENU that shows if the setting is the 'VIVID' mode or what ever but no image of the Video source? I am confused.

[dskall]

Re: TOSHIBA 39L4333D, powers on, no standby, backlight on, won't shut down

On post 19 it looks like you found a problem on your panel pcb. A shorted ceramic cap is common problem there and will kill picture

[Sraros]

Re: TOSHIBA 39L4333D, powers on, no standby, backlight on, won't shut down

On post 19 it looks like you found a problem on your panel pcb. A shorted ceramic cap is common problem there and will kill picture

Ok. I can't find the schematic unfortunatelly..

Vinceroger did you mean the fuse on the board I posted in #19?

What is marked as B1 looks like a fuse to me and it's beeping so looks fine.
I think that little green thing is a diode. So 3caps in total are shorted. Is there a way to find their values without the schematics? :/

[budm]

Re: TOSHIBA 39L4333D, powers on, no standby, backlight on, won't shut down

B1 is the Ferrite Bead inductor.
F1 (Green device with deisignator F1 printed on the board) is the small SMD fuse to the right of B1.
Are you saying C12, C13 are shorted?
if C12, or C13 shorted out then it should have blow that green F1 fuse.
D9 is the protection Diode.
So are you getting 12VDC at both ends of F1 fuse with ref. to chassis GND when TV is turned on?
BTW, since in post #1 you did get 'TOSHIBA' showing on the screen, that means the LCD panel was working.

[Sraros]

Re: TOSHIBA 39L4333D, powers on, no standby, backlight on, won't shut down

I see. I pulled out those caps. They are fine, the short is elsewhere and you are right the fuse is blown. I see from your sayings why I thought it was a diode..

[Sraros]

Re: TOSHIBA 39L4333D, powers on, no standby, backlight on, won't shut down

The short was caused by the AUO IC chip at U209. It's burnt and I can't read it. The panel control board is 39T01-C03. I tried to take from another board the IC which had exact outlook 39T06-C00, but I don't think it's the same afterall.
IF somebody has the board 39T01-C03 T390HVN04.0 and could read to me the IC number of position U209 would be great.

[Sraros]

Re: TOSHIBA 39L4333D, powers on, no standby, backlight on, won't shut down

A summary of what I have:
TV starts without showing anything on screen. Backlights work but I have no image.
Sound comes on but after half a minute it goes out. When I press the shut down button on the remote, the sound comes back for 2 seconds before the TV shuts down. Turning it back on the sound does the same. Stays for a bit then goes out. I repeat no image in the meantime, only backlights work.

Voltages:
12V: 12,20V
NC: 12,20V
5V: 5V
ACD: 3,73V
PWR_TV: 0 when off, 3,25V when on
BL_ON: 0 when off, 3,33V when on
PWM2: 0 off, 0 on
PWM1: 0 when off. When turned on it reaches 3,3-3,7V. Then after a minute (about half a minute after the sound goes off) drops slowly to 1,4V. When turning off again the TV climbs up to 2V and then slowly reaches 0 again.

Voltages to panel:
VF1 VF2: 56V off, 85 on
VF3, VF4, FB1, FB2: 28off, 52 on
FB3, FB4: 3,6V off, 14,5V (up to 22V after a while) on

Then the panel, had a short which now is removed. Replaced the fuse and 12V run as input. I replaced P301-16 with P301-30 1216FW QFN IC AUO GAMMA CORRECTION chip at U209. Voltages going out of the chip appear but don't know how much they should read or maybe the chip is wrong because I took from similar board.

Any other suggestions, ideas?