I have a problem in that the PC running on Windows XP does not communicate with the CNC machine.
I want to eliminate the possibility of the wrong port 1 address.

The address found via the PC control panel is 0378-037F
The Mach 3 config setting screen shows 0x378
When I try to change the setting and "apply it" it just seems to default to the 0x378 setting.

Any help appreciated.

That is fine.
Hood

Thanks.
 Are you saying that the two addresses are effectively the same ?

Yes.

Hood

As it doesnt sound like a port address, not sure what controller you are using but check out the following:
Must have at least one axis is set correctly on the Step and Dir don't forget the port setting for each.
Check:
The EStop is on the correct pin and port
The Card Enable is on the correct pin and port

The best way is to disable the Estop and make sure the card is active by using the jog controls.

What controller or breakout board are you using?

LP

That is the default onboard parallel port address.
Hood

Thanks for your comments.
I have just checked the parallel port cable for continuity on all pins and it's OK

The stepper motor driver is from Routout in UK. I bought it around 10 years ago and it has been fine. My trouble started a few months ago when I suspected a PC problem, but this has been checked out OK but I reloaded the Mach3 software.

There is power to the driver box and I can set limit switches using the auto set facility so the PC is connecting to Mach 3.

I think I must have a setting in the config area wrong.

The e stop is port 1 pin 10.
The X,Y & Z axes are set as specified by Routout.Could you explain the comment ref. the card enable - where is this option located ?

Any help appreciated

I think what is meant regards the Enable is some breakouts require an enable signal, yours mayor may not but should be in the documentation for it.
Hood

Still going thro checks.
It has been suggested that I check the output on the PC parallel port.
When I remove the parallel port cable from the driver box to access the pins I cannot operate the reset button in Mach 3.

In the config. set up for inputs it does not seem possible to de activate the e stop. I guess a safety default.
I get the message "external e stop requested" How do I override this ?

My next step would be to check the X direction pin to ground voltage whilst requesting X axis motion.

Any comments appreciated.

Change the active state of the E-Stop instead of trying to disable it.
Hood