I have a Lincoln 120v wire feed welder, model 140, and while welding, the gun cam unplugged and it arced a little on the plug end, and now, the fan runs, but nothing else will happen, it has been two hours and still nothing, thought it was the thermal overload but, still nothing.. any suggestions? thanks, Andy

There are several things that could cause this:
1. The relay (contactor) that switches on the arc is not closing and it could be bad.
2. The diodes in the power supply are bad.
3. The low voltage transformer is bad.

connect the + lead to the spool gun so that there is power at the end of the wire to make the arc
there should have been a user manual showing how to connect it into the system
try searching -- user manual for ( make and model of ) spool gun

there is no seal at the feed rollers around the wire as it requires the correct gauge wire and feed hole to slow down the loss of gas at that point ( easier for the gas to escape up the wire housing and out the welding end )
the gas is allowed to flow when the welding trigger is operated as that opens a gas solenoid that allows gas to the welding wire tube to exit past the shroud around the welding point

read you user manual well to be acquainted with the machines operation, and if there is a persisting problem talk with your supplier and consider a warranty service check

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Millermatic® 211 MIG Welder - MillerWelds

Make sure the ground clamp has a good connection to both the work piece and to the welder Sometimes the welder connection is overlooked.

Your drive tension is too light. There are rollers that the wire feeds through and they need to be tightened. They should push the wire through the gun but slip if you put the tip against a solid object and pull the trigger. If they do not slip, they will jam your gun. Give the tensioner another turn.

Your Linner of the gun could have a kink in it.

open the area were the role of wire is and check when trigger pulled if any action to feed motor. [wire might be stuck at end, or there usually is a small fuse in that area for feed motor]

You need to have the ground attached to what you'll be welding on. Make sure there isn't anything on the end of your wire. Also, if your voltage is all the way down it won't do anything either. Oh, one more thing, make sure you have a contact tip on the end inside the cone. That will be the copper thing the wire goes through with a really small hole. I know some of this sounds pretty obvious but if I hadn't done these things at least once.....I wouldn't know what to look at either. I also don't know your experience level and want to cover all avenues. Hope you find it!

check main contactor or diode bank.