Help Identifying A Problem With My New (old) Welder!

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I recently purchased a Miller Dialarc 250 AC/DC (not the HF version) and after looking up the serial number I know it was manufactured sometime in 1980. I was told it was working, but didn't have a chance to test it out before I bought it. But for the $100 asking price (including leads and 50lb each of Excalibur 7018 and 6010) I figured it was worth the risk.So I took it to the shop I have access to, blew it all out really well, and set up to test it out. This is where things got interesting.I wired it to a standard three prong 220v "range plug" and plugged it in. After throwing the switch, I heard nothing at first. Then, VERY slowly, the fan started to turn. It was so quiet that I had to have my ear within a foot of the fan to be able to hear it at all. Weird, I thought. I was under the impression the welder would be... louder. I'm not sure why, because it is an electric unit and wasn't under any sort of load yet. So I gave it the benefit of the doubt and tried to strike an arc.I just used a rod they had laying around, it was a 3/16 rod, either 7018 or 6010. When I touched it to the steel, the arc was VERY weak. I had the welder set for about 150 amps, and it looked like it was welding with about 20. Cranked it up to 250, and it looked like it was maybe pushing 30. At 250 amps, it should've burned right through the 3/16 steel I was using, but instead it struggled just to deposit a bead on the surface, not burning into the metal at all.So, what the hell is going on? I knew that it had been sitting since at least 2010, but from what I understand it was tested and working then. (Not positive, but he "thinks" he remembers it being tested in 2010.) The copper plates at the terminals of the welder were caked in crud, so I brushed them off really well and brought them back to shiny copper, but haven't been able to test it again. What else can I do to identify the problem? Any ideas where to start? I'm not an electrician by any means, but it seams to me that it may be having a problem drawing sufficient power? I'm going to check the voltage on the receptacle I used tomorrow, just to double check. And I'll check for continuity in the welder, but that should read just fine since I was able to strike an arc, just a weak one.The only other thing I can think to do is placing an ammeter on it to see how much power it's actually putting through the rod, but even then I won't know how to fix it.I'm hesitant to take it to the local welding supply until I've exhausted all other options, because they charge $150 an hour to work on it.I apologize for the long winded question, but if anyone has any ideas I would be very much appreciative. Thanks!
Reply:Hello and welcome.Start with the basics first. Are you 100% sure you have 220-240v power coming into the machine? You don't know how many times we hear the same sort of issues only to find someone wired the plug or outlet wrong and it's getting power from only one leg. Open up the unit and check the actual input voltage right where the wires tie in to the unit. you should have 220-240v between the two hot leads when checked with a meter. if not, solve that issue first. Keep in mind some units were originally set up to be wired single phase/3 phase, so the wires may not be what you expect. Red is always 3 phase with industrial machines, and isn't used with single phase. You want hot to the white and black wires, green is ground, almost all the time. That throws quite a few guys.2nd those machines were often set up so they could be run on several voltages in the industry. There is usually a set of "jumpers" that can be moved to set the unit for things like 208v, 230v and say 480v power. Make sure the jumpers are set up correctly for your incoming voltage. There should be a diagram on the machine panel most times, but it's also in the manual if you down load it from Miller. Note that the same "model" can often have different jumper positions because they made units for all sorts of industrial applications and the jumper positions for the higher voltage units are different than those for machines designed primarily for lower voltage applications. That means the jumper positions for 230v are not always the same from machine to machine. You need to make sure they are right for your individual unit.Check both of these and see it that doesn't solve your problem 1st..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:My money is on what DSW said, jumpers are wrong or only 120 volts coming in.I've hooked 240 volts to a machine with the jumpers on 460 and it did just what you describe.Here is the jumper configuration for my 1979 model.Last edited by MinnesotaDave; 06-09-2014 at 07:03 AM.Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:Make sure you didnt accidently hook it up line to neutral to power the machine and energize the frame with a line wire instead of the ground/neutral wire.I have seen it done.old Miller spectrum 625 Lincoln SP-135 T, CO2+0.025 wireMiller model 250 and WP-18V torchCraftsman 100amp AC/DC and WP-17V torchCentury 115-004 HF arc stabilizerHome made 4 transformer spot welderHome made alternator welder