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That could have been a factor in my case, and also that I'd wired everything together with alligator clips, so there may have been some sporadic connections. After making a clean build it has been working reliably with the same driver. The driver is mounted on the heatsink near the LD. The...

I'd be interested to hear how that works out if you try it :) There's a PDF doc on the PicEngrave site that shows a cool option using a Maxim digital potentiomter. I might try that one out when I get the chance.

@madmike8: Yes, that schematic describes how I've wired the driver. The cap is 47uf/63V, just something I found in my scrap box, wired close to the driver module. I've got the whole thing mounted onto a large heat sink, probably overkill but it all fit together nicely: Sorry for the poor...

Hi Michael, Since wiring it up cleanly and adding the filter cap it's been working well for many hours of runtime. I've got it bolted to my mini-CNC rig and have been using it to engrave wood and make cutouts from paper and card stock. I found a variant of LinuxCNC that is adapted for laser...

Thanks, yes, that's what I have going on now. There's a 15K resistor in parallel with the pot so current is limited to 1.5A even if the pot opens up. Cheers, Joe

>> Most wirewound resistors are inductive >> Ah yes, the real world, thanks for the reminder :)

Hi Lightning Stalker, thanks for those tips. The scope images I posted were to show whether of not the driver was using PWM and it does appear to be a true constant current driver. I don't have a current probe so instead I set the scope across a 1.2 ohm 5W resistor and ran the driver at 1.5A...

Here are a couple of scope photos. The A009 driver is driving two white LEDs at about 125mA. The first photo shows the output voltage, pretty solid at 6V with not much discernible ripple. The second photo is with AC coupling, 50mV scale and 5uS/div. From the second photo you can see about...

Good idea WizardG, I'll scope it later and post the results.

Thanks for the replies, so far blame seems to be pointing at my sloppy test rig so for my next act I may try again with the A009 driver, a bypass cap and clean wiring. It'd be great if I can get it to work reliably with this driver, it is just about a perfect fit for my project and pretty...

Hi, I'm new to this forum, lots of great info here and a nice community. Maybe someone can help me understand the error in my ways that led to a dead LED (M140) and maybe spare some others from the same fate. My first attempt to drive the M140 was using a home built circuit based around an...