I have aquired an old Lincoln AC-225-S stick welder. It looks like it's in good shape on the inside and the fan runs but I have no arc at the stick. Does anyone have a good procedure for troubleshooting the electrical circuits? I am a beginner welder but have basic electrical knowledge. Any suggestions would be appreciated.
Without some background on electrical circuits/components I would not recommend troubleshooting much inside the unit. Are the electrode holders and cable in good condition? Checking for good connections and ground here is where I'd start. Won't even need to take anything apart to do that. Could be as simple as an electrode holder with a bad connection. They're not really complicated inside, but it is 240 volts/high amps, so if you don't know-don't go! If it's an old unit, could just be corroded connections somewhere. Or possibly an overload stuck open inside the transformer coils. The fact that the fan is running probably means power is made to the transformer. Check them cables out thouroughly. Are there any aluminum connections on the unit? If so, these are real trouble when it comes to corrosion. Put a voltmeter on the welding leads at the power supply and see if there is any voltage. If not you've obviously a problem inside the unit. If yes you still could have something stopping enough amps to establish an arc. Do you have zero arc or is there a "hint" of electrical activity at rod.
Last edited by Thomas Harris; 02-22-2004 at 09:31 AM.
Thanks to all that replied. No, I never take anything for granted. I appreciate all of your ideas. Well I checked the ground clamp and electrode holder and wire brushed the contact areas. I just replaced the switch shaft so I know I'm getting good contact on the switch. I also went out and bought some new rods to eliminate that possibility, but to no avail. It sounds like it powers up when you throw the switch, so I'm hoping it's not burned out. I know how to check back through an AC circuit to see where there is or isn't voltage; is there a safe way to do this with the output from a welder? The local welding supply shop says they have to send it out to be fixed and it'll cost $60/hour! If it's the transformer blown, I'd be better off buying a new welder. If it's just a ground cable, I'd hate to spend a bunch of money and time sending it off. Any other suggestions?
well since you have gone through the machice and its still not working i would just bite the bullet and repalce it that machine new is only 300.00 and you will know that you are the only one who has used it and you most likely will have that machine for the rest of your life....
if the shop is going to charge you 60.00 an hour you know that they will BONE you for at least 2 HOURS plus parts then tax on top.....
so do the math a possible 200.00 to FIX a old machine or throw another 100.00 and get a brand new machine ?
good luck either way...........
Use your eyes ,nose and hands to locate the problem. First Turn the machine on. Can you hear the transformer hum? if you can the problem is in the secondary wiring . IF you can not hear the transformer hum the problem is in the primary power side. Unplug the welder and open it up so that you can see the guts. look for problems at each connection in the apropriate section of the transformer or evidence of a burned out transformer or switch. gently try to move each connection you should find the problem pretty easily as it should be obvious. If you can't find it you must guestimate how much you want to pay for repairs and decide from that I fixed welders for a living and 99% of the problems with the simple ac buzz boxes are obvious. HTH Terry
Last edited by Terry Lingle; 02-23-2004 at 07:59 PM.
Problem solved! First, I gotta say you guys are great. I listened; I learned. Took the back off again. After I looked it over real good, the first thing I checked was continuity across the selector switch. Guess what, there was none! The copper lug that swivels with the switch shaft was caked with crud. After polishing all the contacts up, I put it back together and it works like new. Thanks again!
Originally posted by jgmotto Problem solved! First, I gotta say you guys are great. I listened; I learned. Took the back off again. After I looked it over real good, the first thing I checked was continuity across the selector switch. Guess what, there was none! The copper lug that swivels with the switch shaft was caked with crud. After polishing all the contacts up, I put it back together and it works like new. Thanks again!