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Hi 

I got a Samsung LED TV EU55SJ9000L i see the picture verry vague the back lightnig is working but the brightness control is not working.
When the brightness is adjusted from 0 to 100% no change in brightness.
I changed the T-CON panel but still the same.
My question is which part is responseble for the brightness control or how is the brightness adjusted?

Grts

Rik
 

Hello, this small tv is equipped with mainboard TP.MS3663S.PA671 ,25Q64 flash SPI ,display V236BJ1-P01 Rev. CB When it starts, it restarts, sometimes it doesn't "leave" from st.by, so maybe we can find an update software on usb (or dump for 25Q64). Thank you

Manufacturer: Panasonic

Type: TX-L42ETW5

Chassi: LA35



Hello everybody,

I could determine or measure the following with the device:

Device does not start anymore, stand-by LED lights red when device is plugged in and flashes red as soon as an IR command (key press) is sent via the remote control. Voltages of power supply STB 5V and signal LCD_TV_SUB_ON come from A-board. Power supply starts, supplies P15V and SUB1.1V, 1.5V, 1.8V, 3.3V, 5V, HDMI3.3V and USB5V are generated on the A-Board (stand for about 2.5 seconds). Then signal LCD_TV_SUB_ON goes low (voltages go away to STB 5V) and after about 2 seconds back to high (endless). What is missing is the voltage PNL12V which is switched on by PANEL_VCC_ON2. PANEL_VCC_ON2 always has a low signal and does not change its state. Power supply also provides for the 2.5 seconds the 24V for the backlight. Clocking of LCD_TV_SUB_ON starts immediately after plugging in the mains plug (also without IR command). SOS error code is not output. The over-voltage circuit in IC 5000 pin 7 also does not respond. Attached is the timing diagram from the technical training of Panasonic where I have drawn until when the boot process behaves normally.

In my opinion a mistake on the A-board? Does anyone have a tip?

greetings

Andi

Hello
I have on my table this sony kdl32ex600 with backlight issue. It's a common failure of this psu but i do not find any part faulted on this board.
The schematic it is almost the same, with minor differences with GE3B found at page 56 on this service manual:
https://elektrotanya.com/sony_kdl-32ex600_kdl-40ex600_kdl46ex600_chassis_az1-k.pdf/download.html
Uploaded only the page 56 from this sm to easing the search.
The red led it's flashing 2 times, meaning psu faulty. Indeed the led backlight does not light.
With the PSU outside of the tv, just with one resistance of 180ohm between standby ( pin 1 3,3V on connector CN6150 ) i get this values
on in:
starting with pin 1

1  +3,3V ST-BY
2  +3,3V AC_OFF_DET
3  +3,3V POWER_ON (with resistance 180ohm between pin1 and pin 3)
4  +12,56V AUDIO_12V
5  0V AUDIO_12V_GND
6  0V REG_12V_GND
7  0V REG_12V_GND
8  +12,6V REG_12V
9  +12,6V REG_12V
10  +0,1V BL_ERR
11  +3,3V BL_ON
12  0V DIMMER
13  0V DIMMER_DC
14  0V T-CON_Vcc_12V
15  0V T-CON_ON
All measure done at secondary ground point C6800 GND as reference.
Meanwhile, the led connected to CN6800 will remain with no light at all. The CN6800 will deliver positive 91V.
The negative branch will deliver at CN6801 ( both pin1 & 2 ) just -1V.
In the training manual found always in here at
https://elektrotanya.com/sony_kdl-32ex600_40ex600_46ex600_chassis_az1k_training%20manual.pdf/download.html
at page 56 will say "SHORT" at pin 12 DIMMER for testing the PSU, always with pin 3 POWER_ON connected to 3,3V ST-BY - pin1.
If i'll put a 180ohm resistance between GND and pin 12 DIMMER, then the tension on CN6800 will rise to +179V and the negative from the CN6801 will rise to -5V, the backlight led will light very very weak.
All tension from CN6805 will remain the same, except the BL_ERR will rise from +0,1V to +1,1V.
With only power_on pin 3 shorted by 180ohm resistance to the pin 1, i get this weak oscillation at emiter of Q6816 + Q6817

[URL=https://picturepush.com/public/16067400][IMG]https://www1.picturepush.com/photo/a/16067400/640/diverse/Q6816Q6817.jpg[/IMG][/URL]

With pin 12 DIMMER shorted ( always by a 180ohm resistance ) at GND, the oscillation will change from 250khz 1,6vpp to almost 70khz at 0,81Vpp. as below:

[URL=https://picturepush.com/public/16067401][IMG]https://www1.picturepush.com/photo/a/16067401/640/diverse/20181117-175255.jpg[/IMG][/URL]

Already checked the capacitors C6828 / C6830 together with D6805 / D6806.
Also checked the L6800 ( trafo ) and i've get 5,5mH instead of 5mH, i think it's ok.
All fuse checked, ok.
Q6814 and Q6801 tested under mosfet tester, ok.

[url=https://picturepush.com/public/16067402][img=https://www1.picturepush.com/photo/a/16067402/220/16067402.jpg][/url]

IC6800 & IC6801 gave +9V and respectively +2,49V

Already checked various components all over the board, i am out of ideas.

Any idea or help would be apreciated.