Hypertherm hsd130 interface

The ARC OK and Torch ON are there, but there is voltage out at all, and that is a must for THC to function.
Might need to wire stuff inside the plasma, do you have anyone that can do that?

Yeah, somehow i managed to miss this.
When in doubt, more C4 !!!
Use relays as you have in the drawing for ARCOK, do not wire anything to Mesa, do a test cut and check if the relay closes while cutting. Do the same thing for TorchON but reversed, meaning contacts go to plasma and coil on the Mesa side but do not wire to Mesa just use whatever can give 15-24V and trigger the relay with it see if the torch fires. After this, you can wire stuff to Mesa, one at a time, test, wire, test....
As for the Arc Voltage, find the big rectifiers, usually with big aluminium heatsinks and find the positive and negative, wire two short wires to each, wire 2 of 1MOhm/2W resistors to each of those wires, on the other side of the resistors wire two thinner wires prefferably shielded and send those to Mesa THCAD, mind the polarity, although nothing will happen if you do mix the polarity but you will have no voltage reading on screen.
Make positively and ultimately sure you have the power cord and plug under your foot while adding this, i do that always to prevent someone somehow getting the idea that it belongs plugged to the wall...while i have both hands inside!

bentiggin wrote:

Also, do you mean one 1Mohm/2w on each wire for a total of 2 resistors or two 1Mohm/2w on each wire for a total 4 resistors?
 

1 resistor on each wire, two in total.
So my advice on wiring on the rectifier wont work as this seems to be an SCR controlled rectifier, but there is hope, wire resistors to the big terminals on the picture on the left side, use a DVM to find the torch and clamp connections, clamp will be positive and torch will be negative but you have to remove the torch cap to check as the outer torch nozzle is not connected to any of those.
Are the high voltage/high frequency parts on the other side of that metal wall?