Axcess e feed issue

[roboweldr]

Had an issue with an Axcess e power supply/feeder yesterday. Operator was welding and the wire feed rate would slow down and speed up. Sometimes it would slow and then quit feeding wire completely.
Maintenance changed out the e feeder before I got there. With the feed rolls disengaged, we would press the jog and watch the bottom set of rollers. They would start slow, go slower, and then speed up. Checked wire pull through liner to the feeder - good. Checked roller size and wire size - correct. Inserted a new liner in the stinger/gun - even though the wire pulled through fine. Switched the cable that connects the feeder to the power supply with one from a station we knew the welder was running correctly. Still wouldn't run correctly. Swapped out the power supply - which a Miller tech from hotline told me to try. Nope. I checked program set up on the feeder - correct. Lots of head scratching going on the whole time. Finally decided the only thing we hadn't changed was the stinger/gun itself. Got a brand new one hooked up. Welds better than it did before.
Any thoughts on why this would be the gun? Anybody else ever see this and how did you fix it? What bothers me is that it took us 2 hours to get the op welding product again. Need more training so I can diagnose issues faster.
Thanks.

[cruizer]

Well, could have told you that it was the gun immediately, Tech support should have said the same.

What happens is that one or both of the trigger wires that go through the gun conduit tend to scrape against the copper conduit then short out. This causes the wire feeder to go wonky as was shown.

When you meter it out, merely find the bad trigger wire, and replace it with a spare on both sides. The spare is there for this reason.

You could have easily determined whether or not it was the gun or feeder by paper clipping the feeder to gun trigger terminals. Trouble with this is the Axcess and several other machines will go to jog mode and then error out as there is no weld being done, or merely go to jog mode.

If you had posted the problem here, I would have merely said " Mig gun is pooched" and not much else.

[roboweldr]

Appreciate the response and explanation. Hopefully I retain the knowledge gained and can apply it the next time I see this.