Power MIG 255C Wont Weld

[geezer]

Turned off my 255C evening before last was welding fine, went out yesterday and no soap. Getting power, wire feeding fine, but wont weld. Checked input on back of machine all ok. Any ideas on what to check would be appreciated

[Louie1961]

I would check the work clamp (aka ground) first. I would probably change the contact tip second, and if none of that works, break out the multimeter and see if there is voltage present where the power lead connects to the gun when you press the trigger. After that I would open up the gun and check the trigger switch

[geezer]

I would check the work clamp (aka ground) first. I would probably change the contact tip second, and if none of that works, break out the multimeter and see if there is voltage present where the power lead connects to the gun when you press the trigger. After that I would open up the gun and check the trigger switch

Thanks a ton. First two checks done.

Lets see if I have this correct. To check power lead V I would have to open the gun and see if power present when depress the trigger. Correct?

250L gun here.

Will report back, btw nice bass.

[geezer]

Boy am I confused.

Rechecked ground clamp. Good continuity from machine connection to clamp.

Dismantled gun, took switch out and checked continuity. No problem.

One lead to ground other to tip when switch depressed voltage, bout 28 vdc.

Put work clamp on piece of scrap, welded fine.

My guess is I have an intermittent switch. You agree????

appreciate the reply and post, again, nice bass

[Louie1961]

sure sounds like it. 28 volts seems right. You didn't hit the thermal overload yesterday by any chance did you? Maybe that was stuck. Yeah, nice bass. Caught him in Long Island sound in what is called "the race", an area of narrows between the north fork of Long Island and Fishers Island. I was drifting live eels on the bottom. He was a 40 incher, weighed about 25 lbs IIRC. Biggest I have ever caught, but really a medium sized fish around here. The big ones around here go 50+ inches and 40+ lbs.

[geezer]

don't believe I hit thermal overload but have had allot of birthdays so it is possible.

Thanks again for taking the time to respond

[ccawgc]

If your gun has the open trigger switch. Contacts can get dirty and will work intermittently until cleaned or switch is replaced.

[geezer]

If your gun has the open trigger switch. Contacts can get dirty and will work intermittently until cleaned or switch is replaced.

Thanks for the post, I will try and find a replacement switch on line. Probably go to Harris or Lincoln direct. All still locked down in the mid west