Hi,
Problem: No backlight, but flashlight test shows picture.
Same power supply board (BN44-00667A) and CNL802A connector as in this thread (https://www.badcaps.net/forum/showthread.php?t=50896).
CNL802A has pins labelled as follows
D1+ D1+ S1- S2+ N.C. S2- S3+ D1- D1-
Measured + 226 VDC between D1+ and chassis ground both with and without the plug to the LED strings connected.
Based on my web searches I believe that a problem with the LEDs is likely, but I would appreciate confirmation from someone in this group.
I would also like to understand how the LED strips are organized. I know from above-mentioned thread that the backlight consists of 4 strips of 11 LEDs each (6 left and 5 right side per strip), but I am having difficulty figuring out how the LED strips are wired to the CNL802A plug. Are all 4 strips in series? Does pin 1 (D1+) go to the anode of strip 1 (referring to the 4 horizontal strips as 1 to 4 from top to bottom), then to S1- and so on as follows
Pin #1 --- strip 1 ----- Pin #3
Pin #9 --- strip 2 ----- Pin #4
pin #2 --- strip 3 ----- Pin #6
pin #8 --- strip 4 ----- Pin #7
I came came up with this scheme based on the S pin designations on the labels thinking they were possibly current Sensor points for the power supply. I might be totally wrong, but am ready to be educated by anyone who does not mind helping me out!
I have attached a photo of the power supply board (BN44-00667A) as well as a close-up of the CNL802A connector on that board.
Does anyone know of a place where I can get a schematic for this power supply board? I am quite good at finding schematics, but this one seems to be very elusive. Any help would be greatly appreciated. I know I do not need this level of detail to troubleshoot, but I would rally like to understand how the board works and what it does when it does not work!
I was also curious (sorry this is such a long post!!), but though I found a Service Manual for this TV, there is no schematic and no info at all on the power supply!? Is there a separate Service manual for power supplies??
Thanks in advance for any and all help with this. Its a friend's mother-in-law's TV and it is her sole companion!
Mitch
Problem: No backlight, but flashlight test shows picture.
Same power supply board (BN44-00667A) and CNL802A connector as in this thread (https://www.badcaps.net/forum/showthread.php?t=50896).
CNL802A has pins labelled as follows
D1+ D1+ S1- S2+ N.C. S2- S3+ D1- D1-
Measured + 226 VDC between D1+ and chassis ground both with and without the plug to the LED strings connected.
Based on my web searches I believe that a problem with the LEDs is likely, but I would appreciate confirmation from someone in this group.
I would also like to understand how the LED strips are organized. I know from above-mentioned thread that the backlight consists of 4 strips of 11 LEDs each (6 left and 5 right side per strip), but I am having difficulty figuring out how the LED strips are wired to the CNL802A plug. Are all 4 strips in series? Does pin 1 (D1+) go to the anode of strip 1 (referring to the 4 horizontal strips as 1 to 4 from top to bottom), then to S1- and so on as follows
Pin #1 --- strip 1 ----- Pin #3
Pin #9 --- strip 2 ----- Pin #4
pin #2 --- strip 3 ----- Pin #6
pin #8 --- strip 4 ----- Pin #7
I came came up with this scheme based on the S pin designations on the labels thinking they were possibly current Sensor points for the power supply. I might be totally wrong, but am ready to be educated by anyone who does not mind helping me out!
I have attached a photo of the power supply board (BN44-00667A) as well as a close-up of the CNL802A connector on that board.
Does anyone know of a place where I can get a schematic for this power supply board? I am quite good at finding schematics, but this one seems to be very elusive. Any help would be greatly appreciated. I know I do not need this level of detail to troubleshoot, but I would rally like to understand how the board works and what it does when it does not work!
I was also curious (sorry this is such a long post!!), but though I found a Service Manual for this TV, there is no schematic and no info at all on the power supply!? Is there a separate Service manual for power supplies??
Thanks in advance for any and all help with this. Its a friend's mother-in-law's TV and it is her sole companion!
Mitch
Comment