THC USB issues, 45XP, Dell Tower Windows 10

I am having issues with the THC module dropping out mid-cut. Using the supplied USB cable, SMAKN Digital USB Isolator, Windows 10 running on a new Dell tower, Hypertherm 45XP torch with Langmuir CPC cable. Dry cut completes fine, THC module goes grey shortly into the cut. The PC shows:
Unknown USB Device (Device Descriptor Request Failed) Error Code 43, and Fire Control becomes unresponsive. Our test cut file is the ‘Snap On’ logo from FireShare set at 90 in/min 0.6 pierce. THC test completes fine with 0 volts and 176 volts. I’ve installed and repaired the Fire Control multiple times.


Marc Obenshain

Welcome to the forum…

ok…most likely the file from fireshare is not set for use with the Pro model…in other words it was most likely designed without THC in it.

so open the file in your post processor program and reprocess it…

what post processor are you using?..sheetcam or fusion 360.

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Thank you Toolboy. We are using Fusion 360, I will give this a try.


since your USB device keeps failing, could also be electrical Interference or noise from the cutter that’s messing with the electronics. how close is the cutter to the control box and CPU? if close, separate then as far as possible and try to cut again. Also if the power cord on your desktop has three prongs then use a 3 to 2 prong adapter to eliminate the ground prong. dollar store item.

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Thank you nicaDd,

The cutter is 10’ away from the control box and the PC. There is a tiny amount of resistance between the USB shell and the machine frame, but the THC test process returns reasonable values. Pulling the ground out is an excellent idea. I need to get out and run the post process on my file as well. Thank you guys for the information!


I’d start by using a 3 prong to 2 prong adapter for your desktop pc and any monitors that are connected to it. If that doesnt fix it, pull the electronics box off the leg and try again.

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