MTS 275 problem

[Fallen Tree]

I recently purchased a MTS 275 that has an intermittent problem, it does seem to be becoming more frequent. I'm welding 14ga 1 1/4" tubing with .030 wire 290 WS and 17.5 to 18 V . It will weld perfectly and then with making no changes will not weld. It stutters and has a hard time establishing the puddle and maintaining an arc. As I said nothing changed ground still in the same place and on clean metal. I did find the grounding strap loose from one side of the cable clamp and fixed that and thought I had found the problem however it came back after just a couple 1" welds. Replaced the ground clamp and cable with one I had on a stick welder this clamp was a hobart t-style and did not fix. Mark has suggested that I could have a bad roll of wire or may need to change the liner, running the yellow liner that came with the 10' MB36 gun. It does not seem to me to be the problem I can immediately pick up the mig gun and wire feeds fine very smooth and no jerking of the wire roll. I set the wire speed to 300 and pulled the trigger and ran out 29" of wire in 6 seconds which is 290ipm really close to setting considering lag in pre-flow setting. I videoed the weld and will try to attach the camera didn't pick up what was going on with the wire but you can tell more about the sound. Also videoed the control panel and WFS/A is jumping all over the place. I have not tried the stick or tig function yet. Video will not load will link a YouTube file.

Video of the weld: https://youtube.com/shorts/KrUMZ6s7TBI?feature=share
Video of the control panel: https://youtube.com/shorts/golqiN5KczY?feature=share

[performance]

Seeing the video, it looks like you are an 1 or more away. It definitely is too far off now.
If you have an extra hand, have someone take a look at the wire feeder while you are welding to see if there is any discontinuity in feed. Also make sure the wire spool isn't too tight.

[Fallen Tree]

Seeing the video, it looks like you are an 1 or more away. It definitely is too far off now.
If you have an extra hand, have someone take a look at the wire feeder while you are welding to see if there is any discontinuity in feed. Also make sure the wire spool isn't too tight.

I think the video is misleading at times the cup was almost touching the plate and generally not over 1/2" away. I was trying to walk the cup more than normal just trying to maintain an arc. Did the control panel video tell you anything?
I am going to get the correct liner or a different gun. I just can't figure why it weld so good at times and then with no changes starts doing this.

[Fallen Tree]

Seeing the video, it looks like you are an 1 or more away. It definitely is too far off now.
If you have an extra hand, have someone take a look at the wire feeder while you are welding to see if there is any discontinuity in feed. Also make sure the wire spool isn't too tight.

I found the problem, the guard that covers the bottom drive gear was rubbing on the drive rolls. I was changing to an 0.45 wire and when changing the drive rolls noticed the paint rubbed off on the edge of the guard. I left it off and it welded the 0.45 wire perfectly. Changed back to 0.30 and has welded fine all day. I still plan on getting the correct liner.

I have some concerns about the yellow liner that came with the gun, I think it may have been cut to short. When you unscrew the tip holder the liner is recessed back in the neck about 1/4" you can't screw the tip holder back on and be sure the liner goes into the recess of the holder. If you have wire in you can pull on it and the liner will come out past the neck 1/2" you can also push the liner back in the neck until it is recessed 3/4" this make me wonder if the liner is staying in the tip holder.
Please let me know if you think the liner should be longer.