[Veydron]

Hi guys, I got a chinese cnc 3040z-dq. Recently Im having issues with my spindle. Initially, the on/off switch for the spindle failed to function. I have replaced the mosfet IRF740 and it got burnt quite a number of times. After replacing a new mosfet irf740, initially the on off switch work but after sometimes it failed again. I could ignore the on off switch but right now my spindle spins at irregular speed. For awhile it goes fast and slow after that. I tried to contact my seller but I got no respond. Pls help!

Ps. Can anyone introduce what kind of 2mm end mill that is suitable on aluminum engraving?

[john-100]

If you don't have the circuit of the control board look here :-
https://www.cnczone.com/forums/chine...oc-pw3024.html

with several IRF740 FETs being burnt I would check the motor current to see if its damaged

if the motor is OK then I would suspect the FET is not being switched on hard enough
check the 12V regulator is OK and NE555 output is switching between 0V & 10V
if the output is only reaching 4V the FET on resistance will be high and the FET will dissipate more heat

John

[Veydron]

John.... Thank you! You saved me once again. I went and find this NE555 at my local electronic store and replaced it. Now everything works great. On off switch works, manual spindle speed control works and the spindle speed is stable now. Thank you once again John! You are a life saver!

[john-100]

A great result

glad I could help

John