When Mach3 will not work

Created by: Lester Caine, Last modification: 7 August 2012

It's difficult to test things when nothing works, but the starting point is probably the computer and what we can check on that with simple tools like a multi-meter.

Step one ... parallel port ...

In Device Manager you will find Port (COM & LPT)
( Need to start with directions how to find it ... but even that depends on the version of windows ? )

There should be an LPT1 .. double click and check the resources tab for the address. Hopefully '0378' but if not, make a note of hat it actually is.

In Mach3 Config->Ports and Pins-> check the address for Port1 which should match the LPT port.

When the reset button is pressed, the enable signal on the parallel port should go high, and then low again when disabled. Of cause this gets a little difficult as each breakout board arangement has it's own setting for that, and it may be that it is a charge pump signal.
You can test a simple enable signal with a meter, as you can also do with the direction pins for the axies. The simplest test that you have something is that the stepper motors lock up when Mach3 is reset. If this does not happen, then we need to dig deaper here.
( On the current message string the motors were locking, so no need to deatil this yet )

Step two ... pinout ...

This is obviously breakout board specific, and we are slowly building a library of pinouts. Further contributions to this would be welcome.

For the Taig 2000LE Step and Direction controller, the pinout is
SDBoard 25pinDPinout
fore example.

It's difficult to get much further without a scope to match the step pulses, but if the voltage changes on that pin when the DRO reading is changing that it's likely that the computer is OK.

Odd and sods ...

  1. I've had a couple of Taig Step and Direction boards with blown PIC chips, since they are direct on the connector pins. Checking this out usually just involves fitting a new PIC, but that is difficult out in the field.
  2. On all the Taig controllers there is an in-line fuze which supplies the power to the drivers. Normally when this is blown, the motors turn, but do not have much power. It is worth testing it if you have performance problems.
  3. Room for more ...