Trouble Shooting XMT 304 CC/CV

[hemogoblin]

Long time lurker - First time poster.

Hi,

Since it's my first post, here's an introduction:
I'm the sole fabricator for a small engineering firm in NH. It's mixed media so I work with everything from metal to carbon fiber to polyethylene to wood to who knows what. I do machining, assembly, electronics, soldering, brazing and of course welding. While I'm not a full time welder, it's becoming more important.

On the metal joining front, I've done OA welding and brazing, wire feed, stick and tig, stud (and screw and glue).

The issue that brings me out of the lurking shadows is my xmt 304 cc/cv.

It was working fine, then one day when I turned it on, the stick mode was not working - small sparks and no way it was going to hold an arc. Turned up the amp control and at around 145 it jumped to 999 and stays there even it the amp control is adjusted. If turn the amp control all the way down it sometimes goes to zero and it will allow me to turn the amps up until 145 or so and then it jumps again to 999. Even though the amp display changes, this has no effect on the amount of arc.

For giggles, I tried it in tig mode with argon. The readings on the display act as they should there, but only small sparks again and no arc. It has enough to stick the electrode if I try and that's about it. The lift arc is also not working. It acts just like the scratch start.

For a little more info, here are the readings when I go through some of the modes with the machine set to "panel" and 0 arc control:

Mode; V ; A

V sense; 87.4; 999
Stick; 87.7; 0-145 then jumps to 999
Pulsed Mig; PP.P; PPP
Tig; _._; 0-400
Liftarc Tig; 7.0; 0-400

The plug is set up for single phase with the red wire insulated, taped back to the outside of the power cord and not connected.

Any help would be much appreciated.

Thanks.

[cruizer]

Front display board is damaged. program and contactor control is on it. Likely find another on :www.miller4less.com

[hemogoblin]

Thanks for the help. I'll look into getting a replacement. Fortunately there's someone at work that are very good with electronics and has offered to help.

Is there anything else with the machine that could have led to this? I guess I'm concerned about putting in a new board and having it go bad because of another issue.

I've read many of your other posts, cruiser. I'll be sure the check the tightness of the nuts that you mention. Having opened it, it looks very clean and nothing stands out as a problem. Caps all look good (for what that's worth). No burns or melted bits.

hope to get it going again soon.

[cruizer]

Might be able to fix it, but I'd just send it to a circuit board repair shop unless your "friend" has the proper rework equipment. And no this board fails all by itself. Only board that does not have error codes, just operation problems.

[Miller Welders]

We recommend taking it in to a qualified repair distributor if you can. You can use the following link to find one near you: https://www.millerwelds.com/where-to-buy?buy=1.

Let us know if you have any questions.