I just thought I'd post this to see if anyone has any tips, suggestions or related MIG welder experiences. I have an Airco Mini-Pro 125 MIG welder (115V). The machine is about 20 years old. It was a local dealers demo unit that I bought when I moved here to Michigan so I could work on my cars. It's been a good machine so far. No problems. I did 90% of the needed welding in the Charger with it, also snowmobile trailer, several snowmobile repairs, several side jobs (car builds) room mates had over the years, made my factory-look dual snorkel air cleaner, and it went on the road to a friends house for a year or so to hang new quarters and do other sheet metal work on his '70 El Camino. As of this month, it's on loan to another friend to do some work on his '65 Mustang. Sadly though, when he went to use it, it did not work. The machine has been sitting for several years not being used. He said he pulled the trigger & got a very weak, sputtery weld. He turned up the amperage and wire feed, pulled the trigger, and nothing. No current flow, no wire feed. There is a still a "clunk", which we initially thought was a relay for the wire feed motor (which is not turning), but have since learned is probably the gas valve solenoid opening/closing. A read through the owner manual shows no fuses or circuit breakers internal to the machine, but another friend who's spent a lot of years in the fabrication and heavy repair business says he's never seen a unit without a breaker in it somewhere. 20 years later, the dealer that sold it to me is long gone. Airco was bought up some years back by another manufacturer, and they have turned over parts and service to a 3rd party. So there is a source for parts, but no guarantee of what they will stock for an older out of production unit. I have 0 experience at repairs of this type, in this field. I don't know if any welder dealer will work on it, or how much money I should think about putting into it if I do seek a repair. I don't know if shops that work on welders work on all makes and models, or if I'm s.o.l. because Airco is gone. My friend is on a tight time line to get his Mustang finished, and has already shopped for a replacement. A new Lincoln, that's a little better machine than mine on output amperage, can be had from Home Depot for $360. That's about what I paid for mine 20 years ago. Seems like a pretty good deal to me. For myself, I have my eye on a Hobart 220V unit at Tractor Supply Company, if I can't fix the Airco. Any thoughts?
If you can afford to upgrade now is the time.If your not in a hurry though check out the millermatic 140 as a replacement.I think they are top of the line...(ask anyone that has used one) ...Welders have came a long ways in the last 15 -20 years.. As for your old welder any one that repairs them should be able to fix it.They all are kinda the same on the inside even after 20 years.... Good luck, Steve
Thanks guys. xdrag - If this unit is not salvagable, I'll check out that Miller. jack&dueces - Thanks for the tip. I scoured the wiring schematic for a circuit breaker, but found now. Relays it has...and I'll pull them and clean them up.
A couple of things that was not mentioned was did he use a long extension cord and the outlet he used what size breaker is in it?
Most areas have at least one guy who is good at checking out and repairing welders. I kinda with Jackanddeuces in that it may be a corroded contact or connection that is causing the problem. Plus these units don't like long extension cords very well.
A good thought. But there was no extension cord used that I know of (shouldn't have been needed, was in a 2 car garage, but I'll double check), and it was on a new, dedicated 20A circuit (info. with machine says it needs 15A circuit).
I would take the cover of the welder and clean it up with a blow gun and then clean your contacts. If it is a house garage the outlet might have other items connected to it since most house outlet are jumped from one to the other. Have you taken to your place to try and see if it works?
sometimes the transformers, capacitors etc. can go bad when not used for so long, takes on mositure during the long idle time. just bought a lincoln 140hd awasome welder!!! (from the welding store not a home dopet)
OK all...here's what we've learned. The good news....my buddy finished his Mustang! The bad news...there does seem to be some damage to this welder. My friend (with the lions share of the work done by his Dad, a retired IBEW electrician who did equipment maintenance most his life) started digging around inside the welder. I've never had it apart, and did not see it apart. They tried to do a little diagnosis to help me out, took these photos, and put it back together. I may not be getting the technical naming/terminology right, but there are two diode bridges or plates. These diodes all have a copper strap running off of them. You can see there are (I assume) positive (red labeled) and negative (black labeled) diodes. They bare the IR (International Rectifier) label, and a part #. Everything was looking OK, but they couldn't get power to the tip. Then, my friend noticed this.... As you can see, that copper "strap" is broken (not really burnt) on all of these diodes. I've never seen anything like it. Does anyone know what might cause this? Are these meant to fail, to protect other parts of the machine, acting like a fuse? And what are the odds....they failed due to an extarnal cause, and if I replace them, life will be good..........OR.......they failed because of an internal failure in the machine, and if I replace them, I will only fail these parts again becuase they were not the root cause???
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