Jasic 250F Mig, OC light on, now no power, only fan going.

The welding rod lead has to go into the +ve while the current return which looks like a big alligator clip goes into -ve and is clipped to the metal object you wish to weld.
if you are using mig then check the little black switch under the left zero has been switched to mig.
there is a orange power switch thing on the back of the welder that needs to be checked also .

Nevada MIG-220BZ MIG TIG MMA ARC DC Inverter Welder ...

www.ebay.com.au > Industrial > Welding > Welders

eBayNevada MIG-220BZ MIG TIG MMA ARC DC Inverter Welder Welding ... Nevada Welding machine; MIG Torch; Earth Clamp; Electrode Holder; Safety Mask ..

It looks as though previously you have been depending upon serendipitous earth (a happy accident). Electric welders are designed for the substrate to be earthed.

welder drawing high current.sounds like a earth problem with the house or the unit.

bad computer-its an authorized dealer thing-you can pay 1-200 to get it figured out or buy a HF flux core welder for same price.

yeah-Im all blue in my shop and I said HF...

i would pay the miller dealer to get it fixed.

The Rossi 220bz mig welder comes set up to use gas welding, that is with the Mig electrode connected to the positive terminal, inside the machine.
To use gasless mig wleding, the mig wire must be disconnected from the positive terminal inside the machine and reconnected to the Negative terminal - inside the machine. Open both the side coveres of the welder using a phillips screwdriver. Use a 13mm spanner to undo the hex nut holding the thick copper Mig lead to the terminal named positive, then lead it through the machine to the terminal on the oppisite side of the machine, labelled negative and screw it in place there with a 13mm hex screw. Be carefull not to bump any of the many electric parts inside the machine.
If you run the Mig welder in gasless mode with positive earth and positive elecrode it will blow the household electric fuse.
If you run the Mig welder in gasless mode with negative earth and positive electrode it will work, but the end of the Mig gun tip will get very very hot and start smoking abnormally from excessive heat.
But if you take the side covers off and rewire it (takes about 10 minutes) to negative Mig Electrode, the Mig gun tip remains cool and does not overheat. You will have to cut just one white cable tie, to get an extra inch or so of free Mig cable, so the thick copper Mig lead will reach accross to the terminal on the other side of the machine named negative. Stick the earth lead at the front in the positive terminal.
I did this on my Rossi 220bz mig welder.
http://www.weldequip.com/gasless-mig-wire.htm

make sure your work-piece has a proper ground. and maybe check your gas connection. no leaks. maybe turn gas down.

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

go to your local welding store,sells only welding supplies.like praxair,midwest airgas,they can order you parts.

The contact tip is the main source of power, if the tip is bigger than the wire then you will not get a proper conection, the earth clamp is a essential part of the system make sure you have a good earth and all the conections are tight