50w ebay laser will not fire

[Steve Smith Greensboro]

HI All,
I have the big blue 50w Chinese laser engraver. It has worked just fine for a year. Today the laser suddenly stopped firing halfway through a program run. Everything seems to work fine except for no laser fire. The water flow sensor is fine. The fan on the power supply is turning but I have not checked the output yet (not quite sure how to do it safely) and I have not checked the fuse assuming the fan would not work if the fuse is blown. I have checked and tightened every connection I can find to check and tighten. I am looking for suggestions on what to check next. Knowing I would need to replace the laser tube and the power supply sooner than later when I bought it; I am prepared to do that but wanted to make sure I am not missing something simple and in fact if replacing those components would solve my problem.

Thanks for your help!

[Matt McCoy]

Do you have a mA meter on the machine? If it dropped while cutting, it is likely the power supply.

[AL Ursich]

Have seen many posts like this over the years and it came down to the door safety interlock switch magnet falling off hence no Beam....

[Bert Kemp]

Yes like Al said check the safety switches on the cover .