The old Integra 7766 is still supported. Since we released a better plasma screen using tip voltage sensor, we stopped updating the plasma screen that use up/down signal from external THC unit. We have many user who installed the old screen that you are unable to use. See example here
https://youtu.be/rNXNdOduXRoI have attached the manual and the screen.
There is a section to test THC logic using emulated up/down/arcok signals so you can verify mach, plugin and controller are working properly without firing the torch, similar to dry run.
It may be your external THC device you are using is not turning on the ARC OK signal at the right time.
The other option is if you like to use the latest screen
http://www.vitalsystem.com/arcpro and get all the high-end features in the new screen, you can purchase the tip voltage sensor adapter board and we will replace your old Integra 7766 with the newer model 7866 at no extra charge. You can still use the $350 activation you purchased on the new controller. Please email to support at vital if you like to pursue this option.
regards
VSI Support Team