Recently, my Syil SX3 CNC is doing weird thing.

Symptoms include:
1. lack of control on some to all axis at one time.
2. swap control of x-axis & a-axis
3. doubling or half speed (DRO read 2" move while actual is 1" and vv.)

During the time when this happens MACH DRO increase value when I jog but the stepper does not send out any pulse.

I'm not sure if this is a problem with my parallel port interface board or MACH but the solution is to shut down MACH and restart then everything is OK for a while.

Anyone experience this before?  Anyway to pinpoint the problem?
Thanx guys

Save your xml and any other custom files you may have then reinstall Mach, sounds like there may be some corruption on your hard drive.
Hood

But sometime it would work perfectly fine.
The current version I'm using is R3.037, but this happens on 2.63 also.

Do you have a scope? if so you can look at the pulse coming out the parallel port to see how its looking, if its ok when the motors are misbehaving then its hardware from there out. If it looks bad then it could either be the port or a problem with the software. If the latter is the case then a reinstall may help if not then try another computer if you can or even get a PCI parallel port and see if that cures things.
 A couple of other things to look for is that you dont have any other programmes interfering with Mach, most cant but some like Apples Quick time can play havoc. Also shut down Mach and go to your Mach3 folder and run the driver test and see how that looks.
Hood

The software have been reinstalled the only thing preserved are the <screen> and <profile>.
Have not seen the problem repeat but it's only a short period of time.

Thanx Hood for the guidance.  I'll grab a scope to check it this weekend.