When pressing the test key,the laser head cannot rise and fall normally

1.Problem description:The boot,the automatic focus is normal.When pressing the test key,the speed of laser head rise or fall is too slow or the laser head does not fall.Press the key once,the problem will be solved.
2.Possible cause analysis of failure:Problems with sensor sensitivity,too high or too low voltage at focal point.
3.Solution:In the following state,pressing the automatic focus button.the laser head drops and rises immediately after touching the iron plate,and switches to the manual state when the 1.1mm rising position stops.At this point,adjusting the voltage to 5.5-6V,then switch to the following state,pressing the automatic focus,after that the focus is adjusted to the normal state.