oz9976agn modification

This is a TCL55N3 curved TV. The backlight unit has broken several times, causing the TV to be black at times. Now the light bar has been replaced. Before the light bar arrived, I decided to use the original lamp bead to change the current. oz9976agn reduces the backlight current, and there is no example in the online search. After analyzing the functional pins of oz9976agn, I did not find any pins that changed the current. Some people actually changed the R623-R628 resistors connected in series with the lamp beads. Later, they changed them to protect them after starting up. I also tried it, because my The light bar has already broken several lamp beads, I removed a 150 resistor, and it must be protected when it is turned on. Analyzing the circuit, these resistors are used for LED overcurrent detection. Once you remove one, it will cause the sampling voltage to rise, and then the oz9976agn will have false overcurrent protection. Later, I found the reference drawing to design the backlight circuit. Analysis, I feel that the backlight current of this TV cannot be changed at all, but for me, I am not reconciled, because I also promised the user, I will give you the backlight almost once. So I checked the chip information on the Internet, and found that a repairman occasionally removed a resistor, and later the backlight oz9976agn current became smaller. Although it does not know the principle, I analyzed the circuit design for him to remove the resistor. The resistor he removed was Disconnecting the ADIM from the main board to the power board, my understanding is that it is the consciousness of AUTO and DIM, that is, the main board sends the automatic brightness control to the backlight board according to the image brightness. I can also understand it as the ABL of the CRT? So I followed suit. Remove the resistor. At this time, I turn on the current to detect the current. Originally, the TV's power-on current was 150MA and then increased to about 350MA. Now when I turn on the TV, it immediately reaches about 350MA. I guess this should be because the TV's backlight has been fully adjusted. To thinking, since the current can be increased by removing the resistor, then I should use the voltage and find a way to reduce the current. Later, I added an old-fashioned light-emitting diode to the backlight circuit after removing the circuit to turn on the current. 180MA, and then a 1N4148 diode was added to the ground, and the current was 150MA. I also removed this circuit before, but I changed the current later. I used another method. When the light bar comes back, I will decide the current of the light bar, but if I have a method, I can change the current to a suitable position at will. To be honest, I also changed the P.DIM voltage before. The change of that voltage is almost useless for the current. It is estimated that the control should be pulse width modulation, this is analog control, the first is numerical control, and the second is voltage control.

Backlight Protection Guide bypass method

LCD LED BACK LIGHT INVETER PROTECTION

AT1741 -15 -LED GROUND
BA9741-15 -LED GROUND
BD9211F-14-4k7
BD9215AFV -15 -10K GROUND
BD9222FV -13 -LED GROUND
BD9240-15 -10K GROUND
BD9270F-13-10K
BD9275F-11-1K
BD9276EFV-35-LED
BD9766CVF -20 -LED GROUND
BD9766VF -20-LED
BD9777-14-10K GROUND
BD9882F-14 -LED GROUND
BD9893F-10-82K
BD9896-3-LED
BD9897F-22-LED GROUND
BD9897FS-17-LED GROUND
BI3101A-16 -470 oHM
BIT 3101-2&15 SHORT
BIT3102B-14-47K
BIT3105-19-LED
BIT3193-5-LED
BIT3251/52- 5-GROUND
BIT3713 -5-LED GROUND 
DT8211-9-47K
FA3629-15&16SHORT
FA3630-7&10SHORT
FAN7316 -17-LED
ILN816GN-8-10K
KA7500-1&16 SHORT
KA7500B-15&16 SHORT
KHO803A-5-LED OR 390K-820K
LM2901-6-82K
MAX8722-4-DIRECT GROUND
MP1006-6-10K
MP1007ES-4-DIRECT GROUND
MP1008-4-10K GROUND
MP1009-5-DIRECT GROUND
MP1038EY-2&11 SHORT
MP1060EF-3-LED
MP3810-6-82K
MSC1692-4-220K
OB3316QP-DIRECT GROUND 
OB3362RP-16-22K
OZ5508G/GN/N-3-LED
OZ964-4-LED
OZ9643-1-20K
OZ9643N-20 ohm
OZ965-4&5 SHORT
OZ972GN-8-LED
OZ9910-5-82K
OZ9919GN-8-10K GROUND
OZ9937-14-47K
OZ9938-3-10K
OZ9938GN-3-GROUND
OZ9938Q-3-10K GROUND
OZ9939GN-3-100K
OZ9966SN-15-10K GROUND
OZ9972(24-PIN)-20-1K
OZ9976-11-10K
OZL68GN-4-LED
OZL68GN-4&7 SHORT
OZT1060GN-1-LED GROUND
SEM2005-1-LED
SEM2005-1-82K
SEM2006-5-GROUND
SEM2107-21-LED
SS1091ASN-19-LED
TA9687GN-12-47K GROUND
TL1451-15-DIRECT GROUND
‌TL494-1&16 SHORT