A quick five-minute hack to use the external ammeter while retaining PC control of power settings

EDIT: MORE INVESTIGATION IN PROGRESS. DON’T TRUST THIS.

This article is for the Cloudray M100 Laser Power Supply, but it should apply across the entire M-series of Cloudray Supplies. Full Disclosure: This is an affiliate link. Even if you never intend to order a massive CO₂ laser, just clicking that link will still help us stay afloat – Thanks!

The power-supply comes with this sweet display screen, letting you know exactly how much power you’re actually running! Not necessary, but cool. The problem is that when this is plugged in, the knob on the left side will override the power-setting that your laser control software (lightburn, etc) is sending. Cloudray claims they have a switch on the PSU itself to disable this, but our supply shipped without said switch.

Luckily, this is easily remedied with a pair of diagonal-cutters and a tiny screwdriver!

• Remove the knob itself by pulling straight off
• Insert the screwdriver to remove the back panel
• Remove the PCB/Screen assembly from the housing
  • Gently push on the screen
  • Pry the retaining tab back just far enough for the pcb/screen assembly to move slightly
  • Repeat this for each retaining tab, working around the screen multiple times
  • Once both the PCB and then the Screen have passed the tabs, the assembly will slide free
• Using your diagonal cutters, snip the center tab of the potentiometer
  • You can also desolder the entire potentiometer from the PCB if desired
• Use the screwdriver to bend these tabs for additional clearance
• Reassemble by gently sliding the pcb/screen back into the housing, and pop in the back plate
  • Make sure the PCB slides past the retaining tabs
• Done!
  
  

And of course, we have pictures for all of this:

Bonus: How did we figure this out? / Why does this work?

We knew there were only two options for the layout of this control board. Either:

• 1) There is a custom microcontroller on this control board
• 2) This board has only an off-the-shelf display driver, and passes the other signals through

First, we checked the IC on the board…. if we could look up a part number that would be a giveaway – however, it was completely blanked out. So we investigated, trying to figure out where the signal from the potentiometer (signal is always the middle pin, with V+ and GND on the two sides) was connected to. Probing with a multimeter, we found a direct connection (0.2Ω – close enough!) between the center pin and pin 4 on the RJ45 jack! This points to the pass-through option, so we snipped it – worst case, we’d have to solder it back. We put it all back together and…. we were right!

Welcome to our infodump on doubling the power of your laser cutter! We’ve got a RedSail, but this should apply to the entire genre, so lets jump in!

First of all, links:
Laser: https://amzn.to/4jb3jAE
Power supply: https://amzn.to/3E6LaVD
Chiller: https://amzn.to/3FXQJ9r
Mirrors: https://amzn.to/4cnvjhT
Cheaper lasers I used for a totally unrelated project which are still badass: https://amzn.to/44f9X4f

Full disclosure: Those are all affiliate links. PLEASE click one. It doesn’t matter how many, doesn’t matter which one, doesn’t even matter if you order: if you ever use amazon it will help us keep gliding just above bankruptcy. That said, we did a extensive research before ordering and have been happy with each of the products listed.

Due to a series of unfortunate events (our water pump got unplugged), our laser tube died. It had been slowly aging, becoming less and less powerful over the years, and this provided an excellent excuse for more Speeeeed and POWAH! You see what I did there? You thought it was a meme but we desperately need that 0.5% commission. If you already clicked above… I’m sorry.

Shameless monetization aside, we had a few options, but beyond 100w those options are exponentially more expensive. We decided the sweet spot was right at ~95w, which meant a tube about 8″ longer than our laser cutter… We paired that with an 80w power supply – typically laser tubes perform equally well at 80% and max power, so this should result in a much longer life, especially with the new chiller.

First step, as always, measure everything. We grabbed dimensions off the existing laser cabinet, the chiller, and some random caster wheels that we found in the shop. Next, we threw all of that into CAD to mock up a frame.

A frame isn’t technically necessary, but this will live in a communal shop, and things get bumped – so we wanted to make sure our investment was protected.

Based on this frame, we then calculated the side-panel we needed. This was where the ShopBot came in clutch. We CNC’d the side panel – giving us the exact template needed for welding! So we cut angle-iron to size, clamped it all to the side-panel, and welded up two of them. Our chiller was 12″ thick, so we added some 14″ spacers, and then spraybombed the entire thing.

As some of us worked on the frame-extension, another team focused on the laser itself. We started by printing adjustable tube mounts. And then we modified the file, as attached here: LT2H.FCStd <True hacker skills, changing extensions to bypass automated filters>

With these mounts installed into the laser, we then built a shoddy mock-up of the laser tube so we could mark the new centerline… and with that, it was time to fully commit, and cut out the side of the laser enclosure. We drilled the center, used a compass to scribe a circle much larger than the tube itself, and then used a jigsaw to make the opening, before lining it with some slit rubber hose. We really really don’t want to break the tube against this sharp edge.

The last step before installing the tube was to build a sub-enclosure for the tube itself, to make sure none of the electrons (at 28kv!) or photons (at 80w!) escaped – while including access so we could actually get the tube into the enclosure. While we were at it, one of our members wanted practice building drawers, and knocked out a cute little drawer in the front, just the right size for some 1-2-3 blocks or calipers (the battery never dies!)

With that it was time to wire and plumb the tube! Both are pretty easy, the power supply had the exact same pins are our previous supply, and there are only two connections from there to the laser. For the Chiller, we wired the kill-switch to our laser’s kill-switch input – they both came with XLR plugs, and a straight pass-through was all they needed. Plumbing is equally simple, tubes from the chiller go to both ends of the tube, the chiller gets filled with distilled water, and is turned on – then we grabbed an automotive jack to tilt the entire laser and chase out the last bubble of air in the system.

The last step was also the most tedious: Alignment! First, we had to move the primary mirror forward 15mm (40mm of new tube radius – 25mm of previous tube radius), which was a quick drill+tap job. [Oh! One final link in case you haven’t clicked any of them yet (please do) – this was $12 and I love it.] Then, using small squares of paper taped in front of the mirrors (don’t tape straight to the mirrors, it can cook them), we adjusted the wheels on the laser mount until we were square, and hitting the center of the lens. – just a quick blip of the laser at 10% power will leave a burn mark on the paper to work from. Then, a bit of isopropyl on a q-tip to clean that lens, and move on to the next one! We adjusted the previous lens with minute twists of the set-screws in the back, taking a test shot at both extremes of travel, until we ended up with both locations hitting in the same place. Rinse and repeat for the final mirror, and we’re done! We hooked in the exhaust-fan and it was time to cut!