I'm looking for help with my Samsung ln40c630k1fxza. The set powers up, has sound but no picture. However, shining a flashlight on the screen reveals that there is a picture just no backlight. The last few times the set had been used the screen flickered for a few seconds at startup until a normal picture appeared. Now it will not light.
After reading several threads on this issue in this forum and others I took a chance and replaced the power supply capacitors that have been known to fail in these sets. Unfortunately there was no change.
I've downloaded the schematic for the power supply (bn44-0034b) from this site. Below are the readings at the connector that runs to the main board:
Pin Desc. Reading
1. B13v. 13v
2. 5v_DET. 0v
3. B13v. 13v
4. BLU_ON 2v
5. B13v. 13v
6. E-PWM. 5v
7. GND. 0v
8. H_SYNC. 0v
9-10. GND. 0V
11. B5v. 5v
12. GND. 0v
13-14. B5v. 5v
15. B13v. 13v
16. A5v. 5v
17. B13v. 13v
18. PS_ON. 1.5v
I also took measurements at the connector to the inverter board
1. Vcc B12v. 13.24v
2. FB2. 0v
3. FB1. 0v
4-5. GND. 0v
6. LD. 12.38v
7. LD. 12.38v
All readings were with the tv powered up. Any ideas or next steps?
Thanks.
After reading several threads on this issue in this forum and others I took a chance and replaced the power supply capacitors that have been known to fail in these sets. Unfortunately there was no change.
I've downloaded the schematic for the power supply (bn44-0034b) from this site. Below are the readings at the connector that runs to the main board:
Pin Desc. Reading
1. B13v. 13v
2. 5v_DET. 0v
3. B13v. 13v
4. BLU_ON 2v
5. B13v. 13v
6. E-PWM. 5v
7. GND. 0v
8. H_SYNC. 0v
9-10. GND. 0V
11. B5v. 5v
12. GND. 0v
13-14. B5v. 5v
15. B13v. 13v
16. A5v. 5v
17. B13v. 13v
18. PS_ON. 1.5v
I also took measurements at the connector to the inverter board
1. Vcc B12v. 13.24v
2. FB2. 0v
3. FB1. 0v
4-5. GND. 0v
6. LD. 12.38v
7. LD. 12.38v
All readings were with the tv powered up. Any ideas or next steps?
Thanks.
Attached Files