Need help on an Omtech K40+ issue

Community Laser Talk
1

I use Lightburn, and was in the middle of a small engraving yesterday when my machine suddenly just stopped. The head stopped moving and the beam stopped firing.

The water is fine. If I press the test button, it fires just fine. The safety switches (the one activated by the tray, and the one activated by the door) are all engaging correctly. But it won’t engrave at all. I’ve turned it off and closed out Lightburn multiple times, and when I try again, it stays the same. The software and machine are communicating fine.

Is there some kind of reset to fix this display that says “laser signal: off”? I’m at my wits’ end on this, and have tried everything I can think of. I emailed support at Omtech yesterday evening, but haven’t heard back. If I ever will. Anyone with ideas where to go from here?

laser signal off
laser signal off1920×887 398 KB

2

Turn on the Show All switch in the Console window and see if it tells you anything.

3

Well, I did that as you said, but have no idea what I’m looking for. I’ve even done a factory reset on the machine itself to no avail.

console
console396×369 92.3 KB

Here’s the console. It will frame, and the test button will fire, but the machine still says “laser signal off” no matter what I do.

4

It looks like GRBL is happy, so the issue is entirely within your K40+ machine. Google pulled up a Lightburn posting…

A “Laser Signal Off” or “Water Protect Off” error on a K40+ (usually an OMTech or similar machine) means the laser’s safety interlock has tripped, disabling the beam. It is almost always caused by an interrupted cooling flow, a loose trash tray, or a faulty water sensor.

5

Pretty sure those two switches are working as they should, because by activating them by hand, it changes the display readout of the water protection on/off. But neither of them seem to affect the display that reads “laser signal: off”.

Water us gushing out of the return tube. That indicates the water is working OK, doesn’t it?

Maybe faulty water sensor then?

6

Went here to try something about that sensor.

But in the meantime, it started working on its own! OMG! This thing is a fussy little toddler.

1 Like
7

Do you have a voltmeter? All of this stuff can be easily checked with a standard volt/ohm meter.

Did you try jumping the water protect as he did in the video?

That’s ok for diagnosing, but you need the sensor or one day you’ll lose a tub. Don’t leave it like he left his.

Most of these don’t really use flow meters, they use a pressure switch. This ones from my OMTech China Blue 50W machine.

original-water-protect-switch-0
original-water-protect-switch-01920×2560 433 KB

:grinning_cat:

8

Thank you so much for always being here for us. Just being heard by someone who knows so much more than us makes all the difference.

9

Somewhere down the road it’s going to happen again. Not knowing the cause and hoping it will heal itself, isn’t a very good approach.

Get the tools you need now, then you’ll have them when it fails.

:grinning_cat:

1 Like
10

Good idea. Fortunately, this time it somehow fixed itself. Maybe it was restoring the machine to factory settings, or whatnot. I had my little stick in hand to push the button, but didn’t need to. It decided it didn’t want to be pissy anymore, and just started working.

Looks like replacing the sensor eventually will be messy, what with all the water in the lines. Hope I don’t have to cross that bridge anytime soon. It’s mounted at the bottom of the housing, and way back in there to be reaching in and replacing it. Don’t see an access cover on that end, either. Ack.

Thanks again.

11

Just a remark: this is perfectly fine and no error. It always says “off” when the laser is not actually firing, so if you cut / engrave multiple small objects, it will switch between “on” and “off” continuously, making it actually blink.

12

I don’t know if this indicator reflects the L input or the PWM input… Never looked… :frowning:

:grinning_cat: