[hybridmojo]

I have a FSL laser (just a nicer k40) from 2011. Been working fine. However now the laser fires and burns for only about 5-10 seconds before the power drops off. Ammeter shows 20mA constant. Laser pin has voltage on it. I can see the tube glowing the whole time if I prop the lid open and press the safety switch. Just no cutting after about 5-10 seconds.

There is a slightly darker spot on the mirror right by the business end of the tube. That's all I can find. I haven't got a spare and I'm not sure how to get the mirror out (otherwise I'd rotate it around so the beam lands elsewhere, most of the surface is still OK). I've changed the other two mirrors over the past two years and I clean the lens every once in a while (last time I used it, in this case).

If I pulse the laser (fire, stop firing, fire again), I can move around the work area and leave marks everywhere. So the alignment is dialed in.

I did some simple gcode of a box and it'll draw one side of the box and then get weak and not cut anymore.

Simple test by holding the control panel laser fire buttons and jogging in a box pattern produces the same results. Been searching forums all afternoon and finding people with problems with potentiometers, tubes, and power supplies but none of them sound like this.

Any ideas? Could it be the mirror?

[hybridmojo]

I have a FSL laser (just a nicer k40) from 2011. Been working fine. However now the laser fires and burns for only about 5-10 seconds before the power drops off. Ammeter shows 20mA constant. Laser pin has voltage on it. I can see the tube glowing the whole time if I prop the lid open and press the safety switch. Just no cutting after about 5-10 seconds.

There is a slightly darker spot on the mirror right by the business end of the tube. That's all I can find. I haven't got a spare and I'm not sure how to get the mirror out (otherwise I'd rotate it around so the beam lands elsewhere, most of the surface is still OK). I've changed the other two mirrors over the past two years and I clean the lens every once in a while (last time I used it, in this case).

If I pulse the laser (fire, stop firing, fire again), I can move around the work area and leave marks everywhere. So the alignment is dialed in.

I did some simple gcode of a box and it'll draw one side of the box and then get weak and not cut anymore.

Simple test by holding the control panel laser fire buttons and jogging in a box pattern produces the same results. Been searching forums all afternoon and finding people with problems with potentiometers, tubes, and power supplies but none of them sound like this.

Any ideas? Could it be the mirror?

I banged on the laser out of frustration and it started working again. Then it stopped working. So I banged again and narrowed it down to the potentiometer. DMM shows its working, but once the laser is going, wiggling the knob or banging it makes the laser starting cutting again.

I dont need the potentiometer...