Samsung UE48H6410 replaced Mainboard but backlights doesnt go on

[max789]

Hello, I have a problem with my Samsung UE48H6410SSXZG with the main board BN41-02156A and the power board BN44-00709A. Everything seemed like this, the TV could no longer be switched on, the standby LED always flashed 5x2 times. Backlight was off and no sound from TV. Also made the flashlight test and there was no picture.

I made the following tests:
1. Disconnected the main board from Power Board = backlight works.
2. Connected the main board and disconnected the T-Con = backlights does not work.

So I ordered a main board from Ebay also BN41-02156A but from an Samsung UE48H5570SS. The Seller said, it will work on my TV.
Yesterday i received the main board and installed it. Unfortunately, the TV still doesn't work properly.
The TV seems to start normally, but the backlights remain dark. I also hear the Sound from TV when using the control buttons on the backside of the TV. I made an flashlight test and I see a picture now.
So my main problem is, why are the backlights doesn't go on?

I made some measurements on the Connectors CNM803 and CNL802.

The measurements were made when the new mainboard is connected to the power board and the backlights were also connected.

Which voltage should be at PIN No. 10 BLU_ON/OFF on the CNM803 Connector? I have there only 1.5V.

Maybe the Seller was wrong and the Mainboard does not fit for my TV?

CNM803

1. P_DIM3 = 0.4V
2. P_DIM2 = 0.4V
3. GND = 0V
4. P_DIM1 = 0.4V
5. A13V = 12.78V
6. OD_ON/OFF = 3.3V
7. A13V = 12.78V
8. OD_LEVEL = 3.3V
9. A13V = 12.78V
10. BLU_ON/OFF = 1.5V
11. A13V = 12.78V
12. PS_ON = 3.3V
13. A13V = 12.78V
14. GND = 0
15. GND = 0
16. GND = 0
17. N.C.
18. N.C.

CNL802

1. N.C.
2. 3+ = 148V
3. 3- = 0V
4. N.C.
5. N.C.
6. 2+ = 148V
7. 2- = 0V
8. N.C.
9. N.C.
10. 1+ = 148V
11. 1- = 0V
12. N.C.
13. N.C.
14. N.C.
15. IF2 = 0V
16. IF1 = 0V

[Diah]

of course you need to check the pins assignment on new MB as the old one..... try power the LED BL with eternal source or LED BL tester... yours replacement MB service menu / BL option need to pass yours Original MB

EDIT:
if you dont have Tester or external source to power up BL... you can take out the cable "BLU_ON/OFF" from the mainboards side socket... and connect it via 1KR to PS-.ON on the Power boards side... hope it will come on and u can see what are you doing... one things more DM value very low.

[nomoresonys]

"10 BLU_ON/OFF on the CNM803 Connector? I have there only 1.5V" Yep that's too low, do Diah's test, if tv works with picture, then you received a faulty mainboard.

[max789]

Diah nomoresonys
Thanks for your answers, unfortunately I only got to the tests today.

I made like Diah said and connected the cable "BLU_ON/OFF" via 1KR to PS-ON. The Backlight is working with that trick. In the Service Menu, I selected as Type the "48A1AF0V" and made an factory reset. After the restart, I tested some functions like playing videos from USB, and it worked everything ok. Then I removed again the 1KR and connected the cable to the mainboard. Unfortunately, the backlight again doesn't work. I installed again the 1kr and entered the Service Menu to see which Model there is standing. There is standing Model: UE48H5570. But I have 48H6410. I am pretty sure that the selected type "48A1AF0V" is the right one, because my brother has the same TV but with 55" and at his Service Menu is the selected Type: 55A1AF0V.

I have some questions:

1. Do I have to change something more in the Service Menu to make the backlights working?
2. Is there anything wrong with simply leaving the 1KR permanently connected and just using the TV like that?

[Diah]

Diah nomoresonys
Thanks for your answers, unfortunately I only got to the tests today.

I made like Diah said and connected the cable "BLU_ON/OFF" via 1KR to PS-ON. The Backlight is working with that trick. In the Service Menu, I selected as Type the "48A1AF0V" and made an factory reset. After the restart, I tested some functions like playing videos from USB, and it worked everything ok. Then I removed again the 1KR and connected the cable to the mainboard. Unfortunately, the backlight again doesn't work. I installed again the 1kr and entered the Service Menu to see which Model there is standing. There is standing Model: UE48H5570. But I have 48H6410. I am pretty sure that the selected type "48A1AF0V" is the right one, because my brother has the same TV but with 55" and at his Service Menu is the selected Type: 55A1AF0V.

I have some questions:

1. Do I have to change something more in the Service Menu to make the backlights working?
2. Is there anything wrong with simply leaving the 1KR permanently connected and just using the TV like that?

model to choice ok... but this will not effect the BL..... i talked on searching in S..menu BL option .. there will be many to choice.. or show me the s.menu option

[Diah]

BTW. if you aren't succeed to solve it at S.menu... you can keep the 1KR mode... it will not harm any things

[lotas]

To correctly enter the matrix model in the service menu....

[max789]

Diah
I was now in every menu point and couldnt find something with BL. I made some pictures from my menu, maybe you can see something strange.

lotas
I made an pic from the sticker on my panel, I'm missing the designation at the bottom right like yours in the picture. like " 48A1AF0V".

[Diah]

OK. yours TV 48H6410SSXZG which it had function 3D & 2D to 3D.. the placement boards from 48H5570SS with out 3D function as it showed at service menu... mean while yours TV as from the Socket reading at yours first post it had 3Dimm Zone which are related to 3D function .. so you have 2 Option stay with the mode.... or try active the 3D mode and see the result.

[max789]

I have try to switch on the 3D mode, but still without result. I have now just soltered the 1KR and it will stay there. Thank you so much for telling me about the trick.