Diagnosing my failed CNC controller

[Brad Hays]

I have a CNC router controller from a company called Buildbotics, and I’d like to investigate some into why it just died on me. To replace it will cost $500, so I thought I’d take a shot at diagnosing what’s going on. It’s been working fine for a while, secure and in place. And for no reason, it just doesn’t turn on again.

The first diagnostic step is to observe the LED on the power supply when the emergency stop switch is in both the pushed-in and pulled-out positions. In my unit, the LED is on when the estop switch is in the pushed-in or machine interrupt position, and off when the switch is in the pulled-out (normal machine operation) position. They say this means automatic unit replacement, but haven’t given me any details as to why, although I’ve asked.

I magnified and looked at every square mm of both boards, and I’m not seeing any kind of connection corruption. Everything looks clean and intact.

I completed all the suggested diagnostic steps and was unable to identify any faulty individual components. Estop button bypass resulted in the same permanent power off condition.

My hope is that I can simply replace the power supply and get the thing running again.

Any advice for steps I can take to diagnose whether this is the power supply or not?

Thanks in advance.

 

[ivak245]

The bottom picture is a standard SM power supply. Have you measured the output? (with the load disconnected).

 

[Minder]

This is the problem with many industrial systems, they keep the info proprietary. !
What is the nature of the drives ? Do you know? AC,DC motors? Drive signal?
It could turn out to retrofit with one of the PC based or other systems.!

 

[ahsrabrifat]

Your PSU likely shuts down under load because of a fault. Test the PSU unloaded by disconnecting the controller entirely. If the voltage stays stable, the controller is faulty. If the voltage collapses, the PSU itself is bad. Measure resistance controller +V to ground for shorts.
A low reading suggests protection or shorted components. Try a dummy load to verify PSU stability. Check input TVS diodes and DC/DC converters for failure. Use cautious steps; avoid powering shorts repeatedly.
Here’s a relevant reference on power stages from : adjustable buck converter design.

 

[poormystic]

Have you contacted the technical support team at Buildbotics?
Sounds like a good first step to me... Otherwise as @ahsrabrifat has suggested.

 

[Delta Prime]

Have you contacted the technical support team at Buildbotics?
Sounds like a good first step to me...

They say this means automatic unit replacement, but haven’t given me any details as to why, although I’ve asked.

 

[poormystic]

So, 21st century support. Meh.
Some modern gear seems to be built on the same design philosophy as a ladder, to the Moon, made of stacked chairs.