Logik L40DIGB20 Lcd tv Wont Power on just red standby Led on

[matyka]

Hello,I have this Logik model: L40DIGB20 and it wont power on .
I have just the red standby light ,When try to power up the tv from remote and side buttons nothing happens
The power supply model: MLT668TL
I have only 2 reading from the power supply picture attached with this readings.
Should I have the two 12v pin going to the main board some power ?
Any help would be much appreciated .

[budm]

Re: Logik L40DIGB20 Lcd tv Wont Power on just red standby Led on

The power supply board has to receive the PS-ON (Power supply ON signal) to turn on the 12V/24V SMPS power supply section to get the 12V for the main baord and the 24V for the inverter board but for that to happen, the PFC Voltage booster has to function first.
Per your picture, you do have 2.719vdc at the PS-ON (STB) pin, so you need to check the DCV between the two legs of the main filter cap (450VDC CAP) see if you do have close to 400VDC on the two legs of that filter cap or not.
Is this the exact match of your MLT668TL (top and bottom side)?
Pictures provided by shopjimmy.

[matyka]

Re: Logik L40DIGB20 Lcd tv Wont Power on just red standby Led on

Hello and thanks,I have between the two legs of the main filter cap (450VDC CAP) 392VDC on the two legs of that filter cap.
Sometimes will drop to 385VDC .
What would be the next step ?

Yes the picture are the same top and bottom side (MLT668TL )

[finntricky]

Re: Logik L40DIGB20 Lcd tv Wont Power on just red standby Led on

i had the same problem, on the same set last week, and after spending some time checking voltages, all i had was standby and no power from 12v 0r 24v, removed connections from power supply, just leave mains cable turn on and test 12v and 24v, if you now have the correct readings, connect all the plugs back in, but unplug the inverter plugs from inverter, and test 12v and 24 again, if all is well, the tv will boot. but no back lights.
in my case it was the inverter shorting that shut down all power from the power supply

[michael dranfield]

Re: Logik L40DIGB20 Lcd tv Wont Power on just red standby Led on

Common fault on these sets is a short FET on the inverter board part no A04614

[budm]

Re: Logik L40DIGB20 Lcd tv Wont Power on just red standby Led on

i had the same problem, on the same set last week, and after spending some time checking voltages, all i had was standby and no power from 12v 0r 24v, removed connections from power supply, just leave mains cable turn on and test 12v and 24v, if you now have the correct readings, connect all the plugs back in, but unplug the inverter plugs from inverter, and test 12v and 24 again, if all is well, the tv will boot. But no back lights.
In my case it was the inverter shorting that shut down all power from the power supply

+1

[ReeceyBurger123]

Re: Logik L40DIGB20 Lcd tv Wont Power on just red standby Led on

https://www.badcaps.net/forum/showth...=SSI_400_14a01

Check out my thread not as simple as just replacing the fets you will need the whole controller too.

[matyka]

Re: Logik L40DIGB20 Lcd tv Wont Power on just red standby Led on

Thanks for all your help ,I have checked and yes on SSI_400_14A01 inverter has 3 fets shorted .
I have attached some photos to see the damage on the back .
I order 3 fets and ReeceyBurger123 advice to replace the IC SEM2107
I will let you know when the parts will arrive .

[ReeceyBurger123]

Re: Logik L40DIGB20 Lcd tv Wont Power on just red standby Led on

Nice one also I really urgue you to resolder ALL the little SMD resistors and jumpers buddy if they become lose they can cause the fets to blow. Also replace the caps too, with brand new ones like rubycon ZLJ or Panasonic the caps can be affected when the fets short.

[ReeceyBurger123]

Re: Logik L40DIGB20 Lcd tv Wont Power on just red standby Led on

You also have some resistors to replace that are in front of the fets. The attachment I have of them wont bloody upload

[matyka]

Re: Logik L40DIGB20 Lcd tv Wont Power on just red standby Led on

Hello,I have fix this tv after changing 3 fets part no A04614 and 2 10kohm resistor .Tv been running now for 3 days and still working.
Thank you for all your help.

[ReeceyBurger123]

Re: Logik L40DIGB20 Lcd tv Wont Power on just red standby Led on

Awesome, just be careful if it does blow up again you have another issue. Let us know if you need help again