I’d have to run this past the boss. A constantly running laser sounds risky…
As I stated earlier we’re making this too complicated.
@Grey_Area1 has a normal lps which is pictured in about post 7.
Since this is the case and is outputting around 3.5V for pwm, the input to the lps or the controller has to be shot. We know how the lps works, maybe not the MP6565. We know you can’t control the output to maximum unless it’s got a ttl compatible signal, full range of 0 to 5V.
That’s why I asked him to measure the pwm without the lps connected to it or with the signal cables removed.
Although nice to know what type of controller it is, I don’t think it’s really necessary in this case. At this point if the controller alone only puts out ~3.7V then it has to be broken… wiring hasn’t changed …
Make sense?
Just back-reading as I can’t sleep cos of twitchy legs and it’s snowing so I’m also not looking forward to a half mile walk to my doctor’s tomorrow…
…but…
Everyone’s started talking about the 3.7v we get our of our Leetro but they’re forgetting three things;
- It’s the PWM that measures 3.7v
- So far, that’s ALL it’s measured at; we haven’t been able to persuade it to put out anything like a scaled value proportional to the requested power
- The Laser runs off the DA1 analog, which currently puts out 0v up to 2.0v
If you want the lps to run at 100% you need to apply 5V to the IN pin. It was working, so it seems logical you lost the controller.
It’s worth remembering the original problem, which was that a 6% power setting used to provide a good clear etch, and gradually started to fade, eventually stopping marking the wood altogether. To get the same etch, we had to boost the requested power to 24%. Realising this indicated a total failure at some point, we started looking at “fixes”.
We started with assuming it was the tube…it was the oldest component and the one most regarded as a “consumable”, and the slow degradation rather than immediate failure seemed more suited to that than either the power supply or the controller.
But when we replaced the tube and got exactly the same problem (still needed 24% to engraved) we started looking at the PSU (power supply unit, which is why I’m querying the LPS acronym, just to be sure).
We’ve now tried three tubes (the manufacturer kindly confirming that our first replacement did appear to have something wrong when tested), three PSU’s and hopefully by the end of this week, two controllers.
My boss assures me it’s always been set up the same, ie to use the Analog output. No cables had been moved or machine settings changed prior to us having the problem.
The original PSU is now completely broken…we put it back into the setup to test, and it just gives us error codes now.
Information on the controller card is so sparse I can’t even find a spec. For it (it would be nice if we could confirm what voltage range the outputs CAN deliver…I mean it has a 24v input and a 24v output block…and they do still deliver 24v when tested with a multimeter.
It’s just… frustrating. Whilst I can’t say for sure if the controller is fubar, it does seem that the PSU and the card are both indicated. That means either the original PSU and card failed at the same time, or else Ed is right and we’ve used a replacement PSU that’s incompatible.
But come on…an incompatibility that replicates our original problem almost identically? I mean I know I am the world’s unluckiest man… but really?
Snow and doctors appointments currently slowing the investigation down. Hope for updates next week.
This is a common mistake in diagnostics. Taking someone else’s word for what is okay with it.
Obviously the Shotgun Method of diagnostics (throw new parts at it and hope for a lucky hit) is not working for you.
Start over, and go through EVERYTHING. Make no assumptions about what is right or wrong (including the Boss) and proceed as if you had assembled the machine for the first time. You know it worked, so be logical and patient.
And yeah, having been an electronics technician for 60+ years, I know that frustration part really well.
Just as an aside, I mentioned something about “Worlds unluckiest man” in the last post? Well I bought a little gadget to check the focal length of our lenses on the other (HPC) laser we bought. A device with three parallel laser beams. It arrived this morning and this is how it looks with all three lasers turned on…
Yeah.
F*** you, Ali Express…
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Some problems with that.
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In the history of me checking if I’m right and he’s wrong, I’ve yet to score a single point.
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“Boss” is my jokey name for him. I volunteer to help him because I genuinely believe he makes the best product in his field. As such I’m just a mate offering advice. Whilst that means he can’t fire me, he’s under no obligation to listen to me at all…especially considering 1. above.
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If it comes to a fight, he’s bigger than me!
For people wondering…I can’t work full time cos of my Parkinson’s. It’s not that it affects me every day, and that’s part of the problem. I could get a job…I’ve a degree in chemistry, worked in labs and then sales for 35 years. But I couldn’t KEEP a job. No employer can deal with someone who effectively has to toss a coin and get heads before they go to work that day. They could deal with someone who only works one day a week, as long as it’s the same day EVERY week.
Even if I go to bed feeling great, I can still wake unable to move sometimes.
Only a friend could put up with that, and even then, only for an unpaid worker.
I used to be extremely reliable. It’s distressing to me how unreliable this condition has made me, but I take satisfaction in still being able to help my friend.
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The response from the seller will be along these lines: “Can you use?”
I did not say challenge the “Boss”. That is always a no-win scenario.
I get what you are doing. I do a lot of laser work for cost of materials because I want others to succeed. I am retired and have a livable income, so I can afford to be sort of philanthropic.
Copy t ha t ! ! !
I’m in exactly the same situation. I’ve a well invested pension that despite me taking a reasonable living wage out of it in 2024, is going into 2025 slightly larger than it started 2024. Plus, having had Parkinson’s for ten years now, I’m not really having to plan for the next twenty years, or even ten. Five is a good estimate…but I’m thinking I don’t really want to be around for the last two or three, involving as they invariably do wheelchairs, incontinence and people who greet you by saying “and how are WE today?” like you’re a bloody five year old.
So I’ve decided not to just make a will and sit around hoping my friends get what I want them to have, meanwhile watching them struggle on while I’m alive. I’ve decided we are going to enjoy life now, and don’t worry, I’m paying*.
- Note to freeloaders. Parkinson’s makes me very direct. If you weren’t already my friend, the chances of you getting on the list now are precisely zero, and I will have no shame in telling you so (with a surprising amount of inventive and unusual profanities) should I think you’re taking the piss.
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I wouldn’t mind, but I can see what’s wrong with it. I got the multimeter out and took the back off it. The two lasers that don’t fire have tiny (nigh microscopic) resistors on the board. They’ve blown. I know this because when my shakey Parkinson’s hands don’t quite hit the spot and I end up bridging the resistor with the probe…the laser fires.
But that means it left the factory in that condition, which means QC = zero. If I was younger and/or didn’t have Parkinson’s I’d probably see it as a nice afternoon’s project (don’t get me wrong I’d never have had the hand/eye co-ordination to replace a resistor measuring less than 1mm by 0.5mm…but I could have bridged with a “normal” sized one…there would be room. It would be ugly…but it’s in a box that only I would ever open, so…who cares?) but these days I just don’t have the skills.
Edit: worse yet, they just no quibble refunded me. Now I have to decide where to spend my newly acquired £0.97 ($1.20)…
I jest…I ordered three at the same time, at various price points and qualities. The AliExpress was first to arrive and cheapest. I got exactly what I expected. Let’s hope one of the other two does better!
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Or, more likely, the factory monetized the contents of their Reject QC bin by selling it to, shall we say, opportunists who can pass on the savings.
Two bags of Hall effect sensors from eBay:
The gap in the middle shows where parts going into the Accept bin would be.
There’s a lot of that going on. 
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And also a lot of buying said product in bulk (at which point the $1.20 price probably easily drops to $0.20) and selling exactly the same product elsewhere (koff Amazon koff) at $9.99.
Oh, look…as if by magic…
Y’know what’s sad? I couldn’t find a good quality version anywhere. The phrase has become meaningless because anyone can add it to their product description. But I mean GOOD QUALITY. You know. Wooden box. Velvet lined. Brass. Glass lenses. With switches that feel like it’s someone’s job to click them every day, and disassemble and clean them if they don’t give the proper, satisfying “click” every time. That comes with its own polishing cloth and just possibly, a young lady in a Victorian costume who’s job it is to polish every morning, as she greets you with a “Good morning, sir.”. Very probably in a cockney accent.
Ok I feel I may have drifted from my original point into an episode of Downton Abbey…but my point is, if the only thing on the market is “cheap”, then buyers automatically look for “cheapest”.
Where’s all the good stuff gone?
Or maybe it’s just rose tinted spectacles. Maybe it’s that “man of a certain age” thing. Maybe even Pharaoh Khufu looked out his window one day in 3,500 BC and said “Call that a Pyramid? Now back when I was a lad…”
Back again with more confusion. Unfortunately our contact with the comparison MPC 6565 board can’t provide one, so we’re back to poking the thing with the multimeter.
Here are some pictures of (what I think) are the relevant machine settings.
Our machine has been set on the Analog signals setting for as long as we have had it. Requesting 0-100% power results in the voltage output of 0-2.1v between the DA1 pin and ground on the controller, and exactly the same between IN and G on the power supply. This scaling of voltage is matched by the mA output on the power supply, though its not very linear. I checked the voltage from PWM to GND on the controller and it was 3.72v at all power settings.
I switched the setting in the software to PWM and pressed every button that might conceivably send this to the machine via USB (in this case the “save cfg” and “Save” buttons as shown in the image. It made no difference to the multimeter readings at all.
I do not understand this behaviour.