hypertherm 900 internal thcad

wiring up my hypertherm and would like to check that I'm on the right track. I've hooked up my thcad-300 and a 5volt switching PS internally in the 900 mounting them up where the normal divider board and I believe the pilot-arc board would sit. I'm running 6 wires into the machine from the controller. 2 of them are hooked to J3, a 4 pin connector which has the torch switch connections on it. 2 wires will goto a reed switch which will be wrapped up in the "ground" lead. and 2 more will connect to the freq +/- on the thcad. Wiring of the high voltage to the thcad, is done with silicon wire. One end "ground", is connected just before the current sensor on the main board. This also could have been done on the bridge rectifier positive terminals. The other end is connected to the negative terminals on the bridge rectifier since I couldn't find another location. This is before the large choke going to the torch.

One issue I'm concerned about is HV leaking back into the thcad-300. I am certain my 900 does not have pilot-arc since the connector which would be used for it is bare. That would be J1 on the main cpu board.

Installation of the THCAD-300 and 5v PS


Ground clamp possible torch lead hookup


Torch lead hookup on bridge rectifier.


Here I show J1 which is disconnected, J3 which I used for torch control and a question on the shield for the high voltage side of the thcad300. Do I connect it to the chassis or leave it unconnected?