Red Screen AVHC Troubleshooting

[BrayD]

I recently acquired an old Torchmate 2 system running a Miller Spectrum 2050. I have everything set up and functional, but the plasma cutter isn’t firing.

Plasma cutter works as expected with the hand torch. Automated controls of the THC seem to be working. Air comes on, torch does not. Same results on auto or manual.

I’ve checked all fuses and continuity through the ‘start output’ cables. My guess now is that the torch start signal is bad. Not sure how to check it.

AVHC reading shows slightly negative voltage (single digit) initially, zeros when the torch touches off of the material, then reads negative again (-40V) when it’s supposed to be cutting.

All wires were labeled before disassembly and installed properly upon reassembly at my shop. Slim chance I have this set up any different than the prior owner. He sold it to me when the torch start failed. He was moving and didn’t want to troubleshoot it.

I put a multimeter on the start output posts and tried to measure a signal reading when it should fire, but I don’t have confidence in what I was seeing. Where do I go from here? Any chance the machine torch is bad? How do I check that?

Edit: studied some schematics and determined the start output should just be acting like a switch. Confirmed as I have continuity across the posts when it’s attempting to cut. Traced the wires all the way to the splice inside the machine and I have continuity everywhere. I’m down to the machine torch itself having issues.

[BrayD]

I’m makin sparks! It was the torch. Not 100% sure what I did, but I disassembled everything including the machine plug. Reassembled and it worked. Mystery solution, but that works for me!

[weldguy]

Great to hear, always a good idea tear things down, clean, lube, etc. and reassemble anyway. Post of pics of what your cutting if you get the chance