My initial velocity and acceleration setups were as follows:
X.   500   25
Y   500   25
Z   95   6
A   500   25
I did not vary the z-axis and lowered the velocity to 300 and acceleration to 10 on the remaining axes. The only thing that happened only was noticeably slower movement. The Y axis continued to trip an E stop at the termination of its movement. I lower velocities to 200 to 100 and acceleration to 5 and 1, respectively on all 3 motors ( X, Y & A) with no change in results except slower movement.
There is, however, one notable observational change. Movement of the X and Z directions were accompanied by a low steady hum similar to cat purring. Moment in the Y. direction sounded more like a variable growl, much louder and varying in frequency from low to high to low and resulting in an E stop whenever the Y movement stopped.
I ordered and changed out the parallel printer (db25) cable which I suspected might be faulty. No effect. The Capacitor has not yet arrived.
aahka

Ok can you disable limits in Mach as I mentioned earlier so that we can see if that is where the E-Stop is coming from.
Hood

How do I do that? I went through ports & pins, tried enable limit overload, no change. Can't seem to find a disable limits switch. I'm probably missing something basic, help please.

You simply remove the green tick from them
Hood

I switched off (disabled the limit switches) for all axis. The only Input Signal remaining enabled is the EStop with active low disabled. Still got an EStop when moving in the Y direction only when jogging motion stopped. I noticed that the only Output Signal enabled was the charge pump (port#1 & pin 1). I then disabled the Charge Pump and then jogged in all directions without tripping an estop after multiple attempts to do so. I then turned the Charge Pump back on (enabled) and rejogged in all directions. The Estop returned, again only on Y axis movement and only when jogging stops.  Is it ok to operate with the charge pump disabled? Any other advice?
My 10,000 uf, 50 volt capacitor arrived today. I intend to connect it to my power supply interrupting a short between the positive to negative terminals.  Is that ok or does it need a resistor in series with it?

I have never used the chargepump on any of my machines. Its  purpose was to stop windows toggling the I/O of the parallel port whilst starting. Over the years people have thought of it more of a safety feature in that if Mach crashed the chargepump would stop thus prohibiting the port  being issued with signals, that however may not be the case, if Mach crashed it is just as valid a scenario that the chargepump would continue outputting.




Hood