halfmoon instead of circle

[cheech669]

Hello,

I've got one strange problem with cutting.  It seems like mach3 periodically changes how the motor work.  Sometimes pressing a direction arrow will make 3 motors move while other times everything is normal.  It did it to me during a test cut (just retro fit a plasma).  I wanted to make a 5" circle with a center hole.  It did not move to the right spot to put the hole in, then it cut the outside of the circle as a half moon. 

I'm adding the gcode as txt file and sending a picture of what it made.

[Tweakie.CNC]

Your GCode works absolutely fine here so the problem seems to be with your machine. Could it be an electrical noise issue ?

Tweakie.

[cheech669]

It does this even without the plasma being on.  Even with the breaker shut off to the plasma the machine does not seem to move right.  After a little bit the manual controling seems to work itself out, but when running a file (plasma on or off) it gives me these results.

[Tweakie.CNC]

I presume the toolpath looks OK on your Mach screen ?

Tweakie.

[cheech669]

yes it looks just perfect.  When the machine moves to the starting point though it is not right either, it just doesn't seem to move as much as it says it does.

[cheech669]

now running the machine by the arrow keys I get these results.  x+ travels very slowly  x- goes fast  and my y and a are travelling in seperate directions.  When I left last night all motors travelled the way they are supposed to.

[Tweakie.CNC]

Well, to state the obvious, have you checked that there are no tight spots or binding of the axis travel or cables / hoses snagging anywhere ?
Perhaps check your LPT parallel port cable for continuity and all other machine wiring for short / open circuit including any soldered joints and connectors. Major job checking everything but I think it has to be done.

Tweakie.

[cheech669]

will check it all over.  There is nothing in the way I checked for that first.

[cheech669]

I just completely rewired all the drivers to make sure I hadn't missed anything or mixed something up.  There was nothing wrong and still nothing wrong with the wiring but this is what happens.

I move z+ and my result is x- y- a-
I move z- and my result is z-
I move y+ and my result is x-
I move y- and my result is y- a-
I move x+ and my result is nothing moves
I move x- and my result is z- y- a-

I go into config then outputs and change nothing but click ok and everything changes again for my results.

All the hotkeys are correctly set for each axis

[cheech669]

a is my slave to y