Laser not printing even though it's there

Frustrated from NEast
What the Heck have I done.
Burned a few pieces of wood with shapes etc. No problems, they looked and measured exactly what they should have done.
Then it’s all stopped. 3018 happily shines a perfectly focused beam on to the wood, moves around int the shape it should and burns absolutely nothing. It’s a piece of Pine 1.5" thick.
It was set at 40% and it worked, speed was 250.
Today, exact same settings nothing. Taken up to 90% power in steps. Nothing I’ve also reduced the speed down to about 10. Nothing
The beam is still running on all the test, just nothing burns.
I’ve even tried paper, a big NOTHING.
What’s wrong, please help, madness is setting in, or maybe it already has.
added information. the fire button happily fired at 0.25% Today no, I have it now set at 15% before the fire button would show.
As far as I am aware I have changed NO setting other than as stated for today

What do you mean, “before the fire button would show.”? Is that button grayed? Or are you saying the laser does not mark your material, until you set the ‘Fire’ button at or above 15%?

You list a 3018, which is a very generic listing. What drives this system? What laser do you have? Have you tried another software to see if you get the same results?

Yesterday I could see the laser using the Fire Button when it was set at 0.25%, the button on pressing changed from Grey to a light blue. It still changes from a light grey to a light blue but the setting for power has had to be turned up to 15%.
Before pressing button (light grey)
After pushing button (Light blue)
Very little difference.
The device is a CNC3-3018 Pro. From Amazon originating in China, I believe. 15w 450n blue diode.
I have had ongoing tech problems with the build, I had to go out and purchase a set of nuts that would actually fit the slots being the main problem. The replacements are on that slow boat I think.
Yes I have tried, LaserGRBL, Lightburn and GRBLcontrol . Ditto for all of them. Just no burning today.
So I’ve no idea what’s going on in the we beastie.
Testpiece is a circle within a square approx 1cm square. circle is touching all internal four sides.

This would indicate the issue is not software. The low-end diode laser market is known for having higher failure rates. Your laser may be failing.

Sadly I had a stronger word in mind.
This purchase has not been a good one. The nuts they sent would not even fit in the channel on the framework.
Now if the diode is ‘not working’, Just hope it is covered by their guarantee.
I Will find out tomorrow I suppose, they’ll be getting an email about opening-time on their end.
Think I’d be better just asking for a refund and get a different machine. Limited funds as a pensioner though.
Any suggestions, I want to be able to do etching and router carving type of works.

Just to work with the supplier to see if they can confirm and resolve your issue, prior to asking for a refund. Most of these reputable suppliers want you to be happy with your purchase. All systems in this low-end market face similar issues. The cost has to be reduced somewhere to provide these systems at this price. Picking a different one and starting over may not get you closer to having a working system any faster.

This is a common fault with cheap, low-powered diodes pumped up to high power. It could be that your diode is only rated as low as 3-5W, but ‘pumped’ by pushing more voltage into it than the diode spec allows.

Not uncommon to see them burn out in less than 100 hours use. It will still illuminate, but there’s no power to the beam. A good quality diode, run in spec, can last 100,000 hours or more, but I’ve never seen a good quality diode out of China or Russia, certainly not at anything approaching 5W+.

The other issue is ESD/static bursts. They will kill a cheap diode with as little as half a volt out of spec. Poorly-earthed machines can easily build up enough static to kill a laser diode, especially a cheap one. Add to that that the drivers used in these machines typically have no ESD protection, no over-voltage protection - just a basic electric circuit, often just using a basic voltage divider, rather than an advanced circuit like a BlackBuck 8M

Sadly, you get what you pay for. At least you didn’t pay a lot.

Replacement arrived, and there we go, fully functional laser.
I wonder how long this one will last.
So how many of these am I going to go through ???
Thanks for the inputs.

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