Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: cornwallav8r on October 29, 2008, 02:33:52 PM
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This is the weirdest problem! I spent 2 days trying to find the solution and am about to give up. I have a laptop running Mach3, on a small engraving table previously run with a Vision Engravers proprietary controller unit, and all has been well for the past 3 weeks during setup and tweaking the drivers and motor tuning...while I upgraded the z axis and the stepper driver to a nice Intelligent Motion Systems driver to match the other 2.
Never had a problem setting up the driver or issues with noise or anything...now all of a sudden, after replacing the old crappy z driver with the IMS driver, and setting up the motor steps and acceleration, all hell has broken loose. There is some kind of ground loop or oscillation on the lines, causing all the controlled devices in the control box, including the 3 axes and their motors, the 3 output relays to bounce open and closed, making all kinds of noise and the steppers are running wildly, intermittently, growling.
I thought maybe I had killed my laptop's parallel port. Luckily I have an identical Inspiron 8100 laptop, so I swapped everything except the hard drive, no help. Again, it worked beautifully these past 3 weeks during testing and setup. Uninstalled and reinstalled the Mach engine, it reinstalls and tests with the driver test program, just fine, it is and always was rock solid.
Checked for bad grounds, power lines, all ok. Disconnected the new z axis, still same problem with the other 2, cannot even reset Mach3, it thinks the emergency stop button is pressed, which it isn't, and its continuity tests out ok.
With the parallel port cable off, everything is ok, the drives just sit there, no oscillation of motors or relay chattering.
With the laptop turned off, still ok. As soon as laptop is powered on, the problem starts. Disconnect the step lines from the stepper controllers, the motors stop chattering or moving, just as you would expect.
Any thoughts as to what might cause this???? THanks
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So this happens as soon as the laptop is switched on and not just when you open Mach? Might want to try running off the battery and see if it stops.
Hood
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I believe I have fixed it. Major disassembly surgery to narrow down the problem and you will not believe this...apparently while soldering some large conductors, a drop of molten solder had fallen down in between 2 AC transformer secondaries, and was causing a "noisy partial short" if this makes any sense, it wasn't enough to make smoke, but was slightly arcing, I believe now. Couldn't see it until moving the ocnductors around, right up against the terminal block, it was. After removing it, all is back working rock solid. Onward, chalk that one up for the record books of unusual symptoms.
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Now that would be a hard one to find, looks like you were lucky not only finding it but finding it before you found the smoke ;D
Good you are sorted now :)
Hood