Hi everybody,

I am in the process of retrofitting a Boxford 125tcl lathe to Mach3.
The lathe is nearly finished, except for a few minor (decorative ) issues.

However, about a week ago, my speed controller failed completely.
Here's the deal:

The lathe uses a 600W / 24 Volt DC Motor.
I bought one of these speed controllers of Ebay:
https://goo.gl/V4reE1

In order not to exceed the amps of the board, I deliberately used a smaller power supply with only 400 watts.

Now the controller worked fine for about 1 month, but within 1 day it completely failed.

What's happening is that the little red fault LED lights up everytime a motor is connected to it.
If I power on the machine without a motor connected to the board, the green LED lights up and denotes everything is normal.
But as soon as any sort of electrical load (no matter if a multimeter or a motor) is connected, the board goes into fault mode.

Now, the seller in China seems to have no interest in any support, I contaced him twice by now.
Coincidentally, I have a PayPal despute with a similar (if not the same) seller over a motion controller.
It seems they do not give a **** about support or returns.

Anyways, my first question is if anyone uses a similar board with a similar problem who could give me some advice.

I still have the old speed controller of the lathe.
This however, uses a potentiometer instead of a PWM signal.

Now there are these things which I can get rather quickly and cheaply from Ebay or Amazon, but I have no idea how you would wire these up:

https://goo.gl/fTnJkv
or
https://goo.gl/3M9qpu


The PWM input seems logic to me, but why are there 2 GND outputs and what does A0 mean?
The old speed controller board only has three pins for a potentiometer.
I am not an electrical guy, far from it, so please excuse my silly questions.


My lathe nears completion and therefore these little bugs annoy me the most, because the rest works pretty well.


Any help would be greatly appreciated!

Thank you in advance,

Jon

P.s.: Attached is the manual of my old speed controller for reference