THC-300 not working

[bad-rat-57]

Looking for some help with the start-up of my THC-300. I am unable to get an ARC OK signal from the board. The FAULT light on the unit has never gone out. I have applied 12VDC to the J12,J13 terminals and the instructions indicate I should hear a relay click - nothing.

If I cut with the THC off, my system works OK. With the THC on, the torch moves to the start, lights, and pauses (I assume it is waiting for the ARC OK signal) then shuts off.

I have adjusted the pot for the ARC OK signal from end to end with no luck.

Anybody have any thoughts ?

Thanks.

[Torchhead]

If you put 12VDC on the Arc Ok Volts terminal and got no relay click or arc okay indication then its possible that circuit is not working.

There are "dry contact" (switch) inputs on that same card for using a switch output (like from a Hypertherm 1000 series Arc Xfr output with no jumper mod). If you cannot get Arc Ok indication when you short across these contacts then either the input (opto isolator) is blown (you can't put voltage on those pins) or Mach is not setup correctly to monitor the pins.

Contact your THC300 vendor and get another Sensor card. Before hooking it up to your plasma test it with your THC300 for proper operation. Be sure not to get the Arc OK volts input (that takes AC or DC voltage from a Current transformer or a plasma unit the outputs voltage) with the Arc Okay switch inputs that operate with just a switch closure.

TOM CAUDLE
www.CandCNC.com