Troubleshooting Comet

A place to talk about anything that doesn't fit anywhere else.
Canadian_Comet
Posts: 15
Joined: Fri Dec 04, 2015 12:37 pm

Troubleshooting Comet

Postby Canadian_Comet » Fri Dec 04, 2015 12:47 pm

I have an older Comet with the EMC2 software and it has been great for the last 3.5 years other than having to replace a number of bearings.

Two days ago I was setting up to create a prototype out of MDF and the unit started cutting, then after about 20 seconds it completely died mid cut.

Router shut off, all axis stopped moving, but I noticed the software was still tracking as though the CNC was still moving.

It was a relatively light cut but I thought perhaps I accidentally tripped something or blew a fuse.

Pulled apart the power supply/driver box and checked voltages, had a nice solid 40V supply and the Dlink 5V adapter was also supplying voltage to the relay board.

All fuses were good, could not see anything wrong, no odd smells or indications of hardware damage, so I put it all back together

After reconnecting everything it's the same thing, the software thinks it's moving the router but none of the motors function on any axis.


At this point I'm rather stumped, I am an electronics tech. but I'm not particularly familiar with CNC equipment.

Any help would be appreciated, I have sent an email to Probotix but they have not responded yet and I have a project deadline that is making me very stressed out, as I needed to make this prototype a week ago.

Thanks in advance

beltramidave
Posts: 214
Joined: Fri Aug 21, 2015 8:54 pm

Re: Troubleshooting Comet

Postby beltramidave » Fri Dec 04, 2015 3:45 pm

Do you have the tan colored Probotix controller? Do your motors have power? If they do, you should not be able to turn them by hand with the controller turned on.

Where in Canada are you? I live in northern Minnesota and have a few spare parts and maybe even a controller somewhere. I am an electrician by trade and am fairly familiar with the controller, so maybe between the 2 of us we can figure something out...

Dave

Canadian_Comet
Posts: 15
Joined: Fri Dec 04, 2015 12:37 pm

Re: Troubleshooting Comet

Postby Canadian_Comet » Fri Dec 04, 2015 5:36 pm

It looks more like an off white, it was purchased April 2012, I am in Alberta, so quite a ways from you.

Indeed, with everything up and running I can turn the shafts by hand no problem, definitely not getting power to the steppers.

That is helpful, as I said I'm definitely getting 40V supply and that voltage makes it's way past the fuses which supply power to all the driver boards.

All three are dead at the same time, seems too inconceivable for them to all die at the exact same time, perhaps I will do some more digging and pull the case apart again.

beltramidave
Posts: 214
Joined: Fri Aug 21, 2015 8:54 pm

Re: Troubleshooting Comet

Postby beltramidave » Fri Dec 04, 2015 6:00 pm

4-Axis_ProboStep_wiring_diagram.jpg
4-Axis_ProboStep_wiring_diagram.jpg (756.82 KiB) Viewed 3747 times


Oh, Alberta is a ways away..

I have other documentation on the drivers, breakout boards and such, but evidently I can't attach .pdf files. You can go to Probotix website or the Wiki and find them as well.

Have you checked to see if you get any signals at all from the machine? The easiest to check would be the limit switches. What about the parallel cable itself or your parallel card?

I hate to even ask since you are a seasoned user, but what about the estop? I don't think this would prevent the drivers from powering the steppers, though.

If you want we can take this offline, if you would like to email me.

Canadian_Comet
Posts: 15
Joined: Fri Dec 04, 2015 12:37 pm

Re: Troubleshooting Comet

Postby Canadian_Comet » Fri Dec 04, 2015 6:06 pm

Perhaps it's tan, light in here is horrible.

Cracked it open again, has four PROBOSTEP UX Rev1 drivers, RBX-1 Rev 3 relay board and the controller is a PBX-RF Rev 4.3

Again, 40V and 5V going everywhere they should be going in respect to power supply.

beltramidave
Posts: 214
Joined: Fri Aug 21, 2015 8:54 pm

Re: Troubleshooting Comet

Postby beltramidave » Fri Dec 04, 2015 6:16 pm

Here is the link to the manual for the PBX-RF
http://www.probotix.com/manuals/PBX-RF_manual.pdf

Canadian_Comet
Posts: 15
Joined: Fri Dec 04, 2015 12:37 pm

Re: Troubleshooting Comet

Postby Canadian_Comet » Fri Dec 04, 2015 6:19 pm

Ok, so it looks like the LM317 regulator on the breakout board is dead, 40V and GND on the two terminals and zip on the third, so it would seem there is no power for logic.

It's possible something in the system caused the LM317 to die and when I replace it the regulator will pop again, but I guess it's worth a try.

Canadian_Comet
Posts: 15
Joined: Fri Dec 04, 2015 12:37 pm

Re: Troubleshooting Comet

Postby Canadian_Comet » Fri Dec 04, 2015 6:26 pm

Thanks for the info, it looks like the PC side is not using it's regulator and JP6 is disconnected so I might just pull the regulator from that side and drop it into the side that is dead.

Strange design to use the 40V supply and regulate down to 5V like that, given they sold this unit to me with a 5V supply connected to the relay board I am confused why they would not simply use that one for their primary supply of logic.

I don't know what kind of current the break out board uses, but it's rated for 1.5A and that would mean they are dissipating over 50W which would be a real concern with the tiny heatsink they use without compound.

I have to assume the current level is low, but I wonder why the LM317 died, they are a pretty decent regulator chip.

Canadian_Comet
Posts: 15
Joined: Fri Dec 04, 2015 12:37 pm

Re: Troubleshooting Comet

Postby Canadian_Comet » Fri Dec 04, 2015 6:29 pm

Alternatively for about $7 they could have had a DC/DC buck style converter to drop 40V to 12V then regulated that down to 5V, would have taken quite a bit of stress off the LM317 having to dissipate 35V of the 40V supply voltage at what ever current level.

beltramidave
Posts: 214
Joined: Fri Aug 21, 2015 8:54 pm

Re: Troubleshooting Comet

Postby beltramidave » Fri Dec 04, 2015 6:31 pm

Now you are getting way above my area of expertise. I am a learn as you go electrician with no formal education but lots of years of troubleshooting woodworking equipment.

Hope I helped in some way.

Dave


Return to “Open Talk”

Who is online

Users browsing this forum: No registered users and 2 guests