Another Laser Firing Issue - Please Help!

Hi all,

First of all thanks for reading and any help would be much appreciated. Yesterday our Chinese laser (Shenhui SH-G350) suddenly stopped working between cuts. It has been very well behaved for the past 18 months and has allowed us to build our business but ofcourse we would like to get it back in working order to carry on making products.

We recently installed a new laser tube, we did install another we had to rule it out, I have checked the chiller is on, water is supplied to the tube, the door sensor is working, the program is set up correctly etc. The laser machine works as it should, the fan, light and laser head all work and the program will run but nothing is cut. I have checked all of the wires inside the machine, nothing is loose or hanging off a plug etc, the power supply led is on, when I press test on the power supply the red led lights up but the laser does nor fire.

I have checked the wires to the tube and they are fine, the fan on the power supply is spinning also. I have unplugged the data cable to the power supply and tried to test also but no luck.

So could someone please shed some light (no pun intended) on this issue please or point me in the right direction such as a previous post. I can put up some photos if that would help to diagnose the issue.

Thanks in advance
Scott

have you tried the fuse in the laser power supply box? I saw a fuse in the box while I had the cover off.

You can also check the milliamps to the laser using an everyday multimeter. there is a link to a tutorial in these forums somewhere, I read and checked my laser the same way. Don't ask me where to find it though!
Basically you remove the wire near the mirror end of the laser, not the thick red wire at the other end. you then hook your multimeter between the laser tube connection and the wire and fire it for 3000ms or 3 seconds on 5% power to make sure your connections are good and you get no sparking or arcing then you do the same test at 100% power. Should read about 30mA. Mine was 22mA so I took cover off my power supply and found four potentiometers all lined up which I screwed about 3 full turns each in clockwise direction and boosted amps to 28mA which was the most I could achieve.

I did all this with the power off by the way for anyone who is reading. There are capacitors in there too so you mustn't touch anything. Easy to electrocute yourself if you are a newbie like me....albeit a careful and safety conscious newbie!