When you connect laser to your controller board, please pay attention to the pin positions of 12v+ GND- and PWM/TTL, red wire=12V+, black wire=GND-. Yello wire=PWM+, white wire=PWM-(3-4pin wire). So Red Wire must be connected to the 12v+ pin on your controller board’s interface, Black Wire Must be connected to the GND- pin and Yellow Wire must be connected to the PWM/TTL pin, if you use 3-4pin wire, White wire should be connected to the PWM- pin.
if your controller board’s laser interface pins are in different position, please change the wires position to make it match the positions of + – PWM of your interface. If the wires connected wrong, it will damage the diode and the driver board.
Please add a fan when you engraving or cutting, in case smoke blur the lens damage the lens