millermatic 250 problem

[tribble]

howdy from north ga. i have a millermatic250 i bought new & used around the shop on hotrods & farm equip. i started to use it this week & it is acting up.
i had to replace the "sheath" that the solid wire runs thu. wire was kinking
up at times and could not get voltage to regulate. acts like a stick welder does
when the amperage is turned up WAY WAY to high. it will arc but not matter what i try it is so hot i cannot weld with it. i tried adjusting gas flow,wrte speed
and voltage but cannot change the situation. i pulled side off to b sure a mouse or dirt-dobber had not got inside. everything appears to be intact-not wires off or
signs of problems. any help would be appreciated. retired power co mechanic,
used several welders during the years but love my miller. reccomend them to all my buds. thanks BILL

[cruizer]

IS gas going through, I think you have a failed gun

[kvwall]

I had a similar symptoms a few weeks ago. Turned out someone put a new spool of wire on and they loaded it so it was feeding from the top. After I put the spool on right it fed like a charm. Imagine that.

[tribble]

u can hear gas at the nozzle when u pull trigger. wire is rolling off from the bottom. guage flucuates when trigger is pulled so i'm pretty sure it's working.

[cruizer]

I have a sneeking suspicion that the gas liner in the gun is busted, and your pulling atmospheric into it, to get the welds that your talking about,

[tribble]

problem

i assume you are talking about where the wire comes out of the gun/ i had a new one installed yesterday. i also thougt my wire might be too contaminated as it
has been in machine long time. roll i started with was "spotty" had little places
that looked like rust. put brand new roll of wire in today but no change. thanks
tribble

[tribble]

millermatic 250

i had a new liner put in yesterday. also put new roll of wirein. u can hear gas when u put gun close and pull the trigger. guage flucuates when u pull trigger also

[cruizer]

OK, lets get is straight, your wire speed controls the amperage. You replaced the gun liner (not a sheath). The gun is what the 12' cable is. I'm unsure exactly what your doing.

Now the 250 uses a couple of SCRs for a rectifier.

One may be damaged.

I'd suggest you take the machine in for service.

[tribble]

250 problem

sorry my canadian friend but i dont know what u are talking about. my machine has a wire speed adjustment and a voltage adjustment. neither has any effect
on the problem i am having.

[cruizer]

OK, the wire has a voltage range, for 035 wire, its anywhere from18 to 22 volts.

Wire speed controls both the wire comming out and the actual amperage.

Now 035 needs 185 amps to weld properly

If you had a volt meter we could easily see what was going on. With the wire drive flipped open so it doesn't feed, and your volt meter probs on the neg and the positive terminals on the machine.

Measure from the lowest setting to the highest setting with your trigger depressed.

[tribble]

millermatic

voltage stays around 218volts, cannot adjust. carried to repair shop found a bad
circuit board. new board $600.00, rebuilt board $300.00. having my board
rebuilt. one yr warrenty on new or rebuilt board.