Dear All,

I have one of Chinese laser CNC machine shown in this links

https://www.youtube.com/watch?v=06bgotIiSPw

https://www.youtube.com/watch?v=T4dRT-TXTvg


,The machine was working very well but suddenly the laser beam stopped.
Then we tried to turn it ON again by pressing the laser test button the light back but it very weak, when we tried to increase the power by the variable resistor the light turned off again. do you have any idea where is the problem

thanks for your help