I have had my omtech for about a year now and this issue started about 4 months ago. It was running a job and stopped mid job. The screen began to flash and it kept trying to reset in between flashes.
I contacted Omtech but same as anyone else there were no help. They had me troubleshoot and remove the pins for the X and Y axis. With removing them the machine would power on and reset but would not home. It would crash into the top right corner as if it was trying to home but can’t. The told me that it was the Laser dot that was causing the issue. After further research I saw someone said the limit switches. So I contacted Omtech and they sent me 2 new limit switches. I went in and replaced them and the machine worked for like 2 days and the issue started again. I removed the pin that I was told to remove by the Omtech Technician and it was working again but wouldn’t home. I have searched far and wide through the internet and cannot seem to find this issue that I am having. Everything works fine if I removed the pin that has the limit switches connected to it. Whether I remove the top one or the second one. These are new limit switches so I have come to the conclusion that it is not the actual limit switches themselves that is causing the problem but something else. I am sure it is right in my face but I am just not seeing it.
Please help. I do have some mechanical knowledge but not really electrical looking fro advice because at this point it is silly to contact Omtech for a tech to tell me something that I have already tried and keep sending me more spare parts that isn’t fixing the problem.
I would suspect the 24V power supply, did you see if it gives you the voltages that are expected? If so try to unhook everthing from your controller except the 24V and see if it boots?
The power supplies seem to be rated for less than the actual current required by all the hardware in the machine, but most of them “work” due to their ability to handle slightly more current than their rating. Because they’re operating out of specification, any decrease in performance will push the weak ones into failure.
I assume the “150AF” in your machine description means it has an auto-focus pen and a button on the console to start the auto-focus routine. If that’s so, then the machine also has a honkin’ big stepper motor driving the leadscrews to raise and lower the platform, something like the one over on the left in my machine:
A simple test for the 24 VDC power supply: disconnect the power for that stepper motor to reduce the load on the supply, then see if the controller behaves properly.
My machine has two smaller stepper drivers for the X and Y axes, with a much larger one for the platform motor. This picture shows the X and Y drivers, with the larger platform driver over on the far right:
Each stepper driver has a connector for its power, labeled something like DC 18-50 V Input. It may be a separate two-pin connector, globbed onto the four-pin connector carrying the motor wires, or just part of a six-pin connector with all the wires.
With the power turned off, pull that connector out of the platform driver. Reconnect the home switches if you’ve disconnected them.
When you turn the machine on, it should home normally and behave properly, although it cannot auto-focus or move the platform. You can turn the laser power supply off (the machine likely has a key switch for that supply) and run all your usual jobs: the machine should go through all the XY motions, but won’t mark anything with the laser turned off.
If it now behaves properly, a new 24 VDC power supply with a higher current rating is needed.
Report back and we can kick around more debugging based on what happens.
Part of OMTech’s ham-fisted debugging: remove / disable the home switches. My assumption is it’ll work just fine with those plugged back in and the load reduced to eke out enough juice from the power supply.
I’ve heard so many of these Z autofocus systems driving people nuts. I think you’re on the right track. OMTech has had their share of issues with these also, I understand.
I still stand by if it won’t home, it isn’t really working…
I’m with Enno, Ed and Jack on the 24V supply being a concern and I’d like to explore this a little further if you’re willing.
I’m very curious as to what might be happening here and how OMTech arrived at the red dot as the cause…
I don’t quite follow. These pins you disconnected… were these the motor wiring pins (at the controller)? Did you disconnect the X axis motor wiring, reconnect it and then disconnect the Y axis motor wiring and then reconnect it?
This is really interesting… From your description I don’t see how they arrived at this conclusion.
Do these switches have a lever or button that clicks, or are they sealed units with no visible moving parts? The more industrial machines use a Hall effect sensor that isn’t exactly a switch.
Switches and sensors rarely load or overload a power supply unless they’re wired incorrectly or short-circuiting controller power to the chassis of the engraver. This happens often enough on the less expensive or hobby level blue diode lasers that it’s worth checking the wiring to see if this happened.
I’m intrigued by the engraver working normally for a short while after changing the switches.
What material do you usually engrave?
When you changed the switches, did you clean, lubricate or adjust any moving parts?
Is any of the switch wiring pinched or damaged at all?
My thinking is that if the wiring was moved a little when the switches were changed a short-circuit or high current draw may have stopped long enough to let the power supply work properly for a while. After some time the wire can relax and fall back to where it was. This is the only thing that I can imagine that would clear up a power supply fault and allow the fault to return.
Any other wiring that was moved or nudged when the switches were changed is now suspect. Please inspect wiring for mechanical damage and let us know.
As part of this, I just discovered the DMA860H stepper driver in my machine can run from:
18~80 VAC or
26-113 VDC
It is, of course, plugged into the same 24 VDC supply as the X & Y drivers and the controller.
The power supply’s 6 A rating seems underwhelming, given that just the three stepper drivers add up to either 9.3 A or 11.7 A, depending on whether you think the “average” or “peak” current value is relevant.
I may be cynical, but the evidence suggests I’m not cynical enough.
My red dot had a short causing trouble in my 50W but problems were solved after repairing the wire. If the red dot is on the same psu and it was in my machine, it could cause weird behaviour so not totally untrue.
The Omtech Tech has me disconnect the top and middle pin on the Main Board not the drivers. The white board to the left of your image. Once I disconnected the middle one everything worked but not the limit switches.
When removing the connections for the drivers meaning all separately. The problem didn’t change only when I remove the connections on the main white board, does it stop blinking and begin working without the limit switch. It does seem to be the 24V power sipply. But its weird that once you remove other sources of power that it should work again but it doesn’t. Also I removed the LEDs oddly enough they burned out like 5 months after having the machine.
I cannot follow the state of the hardware, so please upload pix of the current wiring at the controller and a description of what’s happening with those connections. Changing unknown things and reporting it doesn’t work is not helpful.
If you have not already done so, set it up as I suggested earlier, take pix, and report what happens.
