K40 stops mid-job. No issues while using PSU or painel test buttons. Ideias?

I used my k40 for about a year, but recently it started to stop mid-job when sending a project from the same always used laptop using k40 whisperer or meerk40t. The laser fades and a second later the head stops. It stops randomly, but overall, I can’t get the beam on for more than 30 seconds. However, when the laser is trigged directly from the PSU button, it can go forever. The beam is also unaffected when using the test button from the panel. Points that I have covered:

-No recent hardware or software modifications;

-The machine is properly grounded;

-The machine has an EMI filter installed since its first operation;

-The machine has no water flow sensor or door switch;

-Air and water pumps working normally.

-Different USB cable resulted the same issue;

-USB power saving settings are off;

-PSU was replaced, but the problem persists.

-It runs a M2 nano julong board from Lihuiyu studio labs.

Any ideas on what could be happening and how to solve it? Thanks for the assistance!

Since you can force the LPS HV output to continuously on, it sounds like the LV power is fading/shutting down.

Given so much of the machine is affected I would suspect the 5 or 25V supply going bad or a connection of those voltages at the Nano.

Look for a wiring problem. i.e. connector pins pushed out, loose, or partially broken.

@ the LPS I would measure the mains,
;then the 5 & 24VDC outputs.
;then I would do the same at the NANO.

Note; stay away from the HV output and the tubes anode!

You may have to set up the measurement during running to be able to see it go away.

When it fails is the red LED on the LPS on or off?

Post a picture of your LPS and controller showing the wiring.

This is a very common problem - and lots of people experience it intermittently. I can run for weeks without this happening, and then have a couple in a row.

The good news is that IME Meerk40t’s USB driver will recover this without a hitch 9 times out of 10 if you simply unplug the USB and re-plug it in. (1x out of 10 you will need to start again.)

@tatarize ??

Thanks for your input Don! I wasn’t able to test your hypothesis so far (the machine is not located at my place), but when I do I will keep you posted.

Unfortunately since the machine started presenting such behaviour, it never returned to the normal operation. I’m afraid it might be hardware related issue indeed. I will proceed with Don’s suggestions and return with the results as soon as possible. Thanks for the assistance!

Results from another round of testing:

-All connectors double tested and should be normal.

-LPSU mains are consistently at 220VAC.

-24V/5V PSU mains are consistently at 220VAC over the entire course of the job.

-24V/5V PSU output is consistently at 23.3/4.7 VDC. I noted minor 0.1V variations between standby and cutting states.

-LPS has a green power LED that is constantly green when the machine is on. There is no “beam on” red LED.

-The “Laser on” LED in the control panel light indicates correctly when the laser is on during mid-job. Once the machine stops mid-job, the LED goes off as well.

-The M2 Nano receives 24 and 5VDC as expected from the PSU.

Here are a few images that might help.

PS: the first run after letting the machine rest overnight seems the longest.

PPS: the machine also has a 12V PSU for a smoke exhaustion fan.

Are you watching the meter when it stops? Are these supplies on when the job stops?

Post a picture of your control panel and another of the wiring into the LPS.

-------------- Observations -----------------

…in your diagram, I do not see a ground wire between your 24/5V supply and the LPS?

Yes, I am watching when the job stops. The 23.3/4.7 VDC remains unaltered before/after the stop.

Sorry for the incomplete diagram. There is a ground wire connection between these terminals indicated by the red arrows:

The M2 nano was the source of the problem. I replaced it with an M3 nano and everything seems back to normal.

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