I ran some tests on TDA3508 , first I measured the voltage on pin 19 soldered to the circuit and got 1.74 V with both maximum and minimum contrast; then I isolated pin 19 and measured only the voltage on the pad, getting 1.46 V. in the diagram it says that it should be 3.7 volts on pin 19 ,with the pin disconnected from the circuit, the image became completely devoid of contrast.
https://drive.google.com/file/d/170q...w?usp=drivesdk