mega arc 400 amp help!

[rupp_centaur]

Hi I am looking at a "mega arc" 400 amp ( as far as I can tell from the adjustment dial) and has a four cylinder ford engine and is trailer mounted. The engine runs great but the welder will not work. It will barley arc on the "idle" setting and at fast engine speed won't do anything at all. Amp and voltage guages are on zero and don't move. AC output/ oulet works ( just tried some power tools and a shop light on it, didn't check it with a meter to see if it is right on ). Fuses looked good behind panel. What could be wrong with it?

Thanks
Don

[calweld]

First thing always, I check, is the brushes. Easiest way to get to them is to pull the lower front panel off (under the gauges and controls). Since you still have 120v output, though, I kinda doubt that's your problem.

Hobart (pre- ITW) generally created the model numbers, based on amperage at 60% duty cycle ..... I have a MA200, adjustment dial goes up to 325 amps, I have pegged the amp gauge well over 350 amps. I'd suspect, what you have is actually the MA250, just a guess.

Thermal arc acquired most of the heavy stuff, after ITW bought Hobart, you might check with them. Also, there is a shop somewhere, come up on this board several times in the past, I THINK maybe in New Jersey???? Apparently they have all the old owners manuals and service manuals, maybe even some parts. Try the search function, maybe it will come up, have no idea what terms to use ......

You could also fold the front panel down, take a quick look-see at the pc boards, see if anything looks obviously burnt. There are a couple places that specialize in pc board repair on welders, again, do a search.

I can tell you, based on my own experience with the MA200, same Ford engine, this machine has one of the sweetest CC arcs around, even the Millers of the time couldn't beat it, that's probably why ITW bought them out. But unless you can get it cheap enough, may not be worth messing with. Still a 25 year old machine .... with no factory support to speak of.

[lars66]

Yes check all the brushes to be sure they are free in the holders. Try C&Mwelding services in Celina Ohio for parts 419-584-0008.