Samsung tv no backlight

[xorium]

Hello hope you guys can help me out. I have a samsung tv no backlight problem.
I have power supply l40gf_ddy bn44-00666a.

When i measure on cnl802 i dont have a voltage on pin 7 s3+.

When i make a bridge from pin 1 to pin 7 the tv shows backlight.

I replaced the power supply but still the same problem.

What can the problem be?

[dick_barton]

Re: Samsung tv no backlight

Any photo's of the circuit boards?

[xorium]

Re: Samsung tv no backlight

I get on connector cnl802 when tv is on :
Pin 1 214 - 215 volt
Pin 2 214-215 volt
Pin 3 184 volt
Pin 4 184 volt
Pin 5 0 volt
Pin 6 0 volt
Pin 7 0 volt
Pin 8 0 volt
Pin 9 0 volt

[xorium]

Re: Samsung tv no backlight



When i disconnect the connector i get only 214 volts on pin 1 and 2 the rest is 0 volts.

[tvtimmy]

Re: Samsung tv no backlight

Take a good look at the connector for a small burn mark on the cable going to the mainboard.

[budm]

Re: Samsung tv no backlight

I get on connector cnl802 when tv is on :
Pin 1 214 - 215 volt
Pin 2 214-215 volt
Pin 3 184 volt
Pin 4 184 volt
Pin 5 0 volt
Pin 6 0 volt
Pin 7 0 volt
Pin 8 0 volt
Pin 9 0 volt

You have open circuit in the LED sting, that is why the Voltage went up to 215V.
Pictures provided by shopjimmy.

[xorium]

Re: Samsung tv no backlight

You have open circuit in the LED sting, that is why the Voltage went up to 215V.
Pictures provided by shopjimmy.

So how do i fix it? And is it save to make that bridge to make the tv working?

[xorium]

Re: Samsung tv no backlight

Take a good look at the connector for a small burn mark on the cable going to the mainboard.

Dont see any burn marks.

[budm]

Re: Samsung tv no backlight

You will have to open up the LCD panel assembly to get to the LED assemblies, if you bypass the LED strings that have open circuits then you will burn up the power supply.
What is the LCD panel model number?
And what is the model number of the TV?
Always provide the model number when asking for help.

[xorium]

Re: Samsung tv no backlight

You will have to open up the LCD panel assembly to get to the LED assemblies, if you bypass the LED strings that have open circuits then you will burn up the power supply.
What is the LCD panel model number?
And what is the model number of the TV?
Always provide the model number when asking for help.

The model number is:samsung ue40eh5300
And i didnt open de lcd panel yet.
But is see this sticker inside on the metal: cy-DF400BGLV1H.

Is it very hard to open a lcd panel? Never did it before.
I am not a noob to repairs is also repair phones,tablets,laptops and such.

[budm]

Re: Samsung tv no backlight

The strips look something like these:
https://www.mtvparts.com/product-pag...d3ge-400smb-r2
If you search 'cy-df400bglv1h' you will see lots of info.
It can be done VERY CAREFULLY, I do not have the instructions but you probably can find them on youtube.

[xorium]

Re: Samsung tv no backlight

The strips look something like these:
https://www.mtvparts.com/product-pag...d3ge-400smb-r2
If you search 'cy-df400bglv1h' you will see lots of info.
It can be done VERY CAREFULLY, I do not have the instructions but you probably can find them on youtube.

When i open the panel how can i check the strips? If they are the problem?

[xorium]

Re: Samsung tv no backlight

If i replace a strip do i need to replace all strips? Or only the faulty ones?

[vinceroger69]

Re: Samsung tv no backlight

This first video will show you how a tv is stripped down to get to the leds
https://www.youtube.com/watch?v=5rwLDxKgZIA
This video shows you how to test a led
https://www.youtube.com/watch?v=eEJoPCa7Kt0

you can just change the faulty led if you have a hot air station/soldering iron or just replace the whole strip there usually a part number printed on them.

[xorium]

Re: Samsung tv no backlight

How can i search for the leds that i can solder with hot air station?
And any idee if i open the lcd panel what the best way is to store the panel till i get te parts so no dust get on it?

[xorium]

Re: Samsung tv no backlight

Found 1 led burned. What leds fo i need to order 3 volt or 6 volt?

[xorium]

Re: Samsung tv no backlight

I replaced all leds tv is working tnx for the help.

[vinceroger69]

Re: Samsung tv no backlight

Thanks for the update glad you managed to fix your set sorry i missed your last two posts i would of replied if i had seen them.

[shani]

Re: Samsung tv no backlight

Hi guys, I am having same problem, I managed to change the two leds on strip, I tested the led strip with led tester and all the led worked fine until i have connected with tv led connector and plug in the tv.... I hard the pop and same led blow up again .

Tv comes on and i can see the picture with torch light but leds keep blowing up

I have voltage only on 1 - D+ and 2 D+, When i switch the tv on voltage goes up to 221 the comes down to 218 on these two connections. I have no voltages on other pins.

[budm]

Re: Samsung tv no backlight

1) What is the specification of the replacement LED's?
2) "I have voltage only on 1 - D+ and 2 D+, When i switch the tv on voltage goes up to 221 the comes down to 218 on these two connections. I have no voltages on other pins." That means the LED power supply output is not seeing the load. The LED+ is the output of the Voltahe boost converter circuit that feeds the Anode of the LED's strings, the LED - is the Cathode return of the LED string. The LED strings looks to be connected as one big LED string.
3) What is the part number of this power supply board? BN44-?????
4) We need straight shot pictures of the whole top and bottom side of the power supply board.