Junk Lincoln 140 C ??

[jjeff]

So I have a Lincoln 140 c has infinite amp and wire speed adjustment about 10 yrs old. Never worked correctly like my old Lincoln 100 or 125 amp with infinite settings. Tried big and small rolls of various brands mig/ and flux core wire, currently have .035 flux core in it. Changed out feed rollers multiple times, they are the knurled ones currently, cleaned out liner played with all settings infinite number of times. I'm at a loss. It will produce a decent arc initially than seems like it's cutting out or cuts back almost like I'm trying to weld rusty or non prepped steel. Yeah my old smaller Lincoln ran and worked flawless forever and I'd hit the auto shutoff for duty cycle frequently, unfortunately gave it to a buddy. Suggestions what to test and look at are appreciated at this point I'm all ears.

 

[TripleS]

Try flipping the polarity on it. I had a lincoln once that you had to flip the polarity one way for fluxcore or the other without flux. It is the two connections in the picture under the tensioner

 

[CliffordK]

Number 1... make sure that if you are not using gas, you are using a flux core wire. It should be obvious, but wasn't obvious to me 40 years ago. With non flux wire it will sputter all over the place.

As far as wire feeding, I had difficulties with an old Harbor Freight welder. The issue was that the upper tensioner housing was plastic, and cranking it down tight enough to feed and it bottomed out. Some careful filing and I gave it clearance. But, I also liked to back off the tension when not in use as the plastic housing seemed to deform with a memory effect.

Anyway, get the right wire and it should work OK, although I have seen complaints that the lower powered machines can't maintain a constant power very well.

 

[jjeff]

Thanks for the input, tensioner is cast aluminum I believe, liner is steel it's definitely not the lesser caliber of a HF welder. No gas, and polarity is correct. It's a heavier transformer welder with limited use cuz it never worked like im used to unfortunately it was purchased new at a charity auction or would have been returned yrs ago. Finally tired of looking at it and feel the need to do something with it.

 

[California]

Could a bad capacitor cause that, a good start then worse?

 

[jjeff]

Try flipping the polarity on it. I had a lincoln once that you had to flip the polarity one way for fluxcore or the other without flux. It is the two connections in the picture under the tensioner

So run it like I'm mig welding? Always thought flux core is reverse polarity, which it's set at currently. I did double check after your post including the connections all are tight and corrosion free with no signs of arcing. Darn thing still looks new in there lol. Btw I've tried mig on it with a tank and polarity changed to normal does the same thing.

 

[jjeff]

Could a bad capacitor cause that, a good start then worse?

Unsure? , next step is to pull the cover. Definitely been missing the convenience of flux core welding on thinner metals over the years. Apprehensive of throwing new or used parts at it unless I can figure out what's bad. Almost done with a big spool of mig wire on my 210 plus the tanks low might just convert it to fluxcore to use the spool in the Lincoln.

 

[jjeff]

Could a bad capacitor cause that, a good start then worse?

Any chance you know what values it should have? Do capacitors get worse over time meaning the length of time it functions somewhat ok consistently gets shorter? I think I have a multimeter that can test capacitance. However haven't done much electrical testing for almost 15 yrs though and then I wasn't very good or did testing on stuff consistently, I know enough to get me in trouble or keep me out of it. lol. Currently hoping it's not a circuit board.

 

[California]

I don't know enough about welder circuits to know if a failing capacitor could do as you describe. But that and the rectifiers are the only things in there, that might gradually fail as the welder warms up. Just an uninformed guess on my part.

Anybody know more about this?

 

[yomax4]

Flux core needs to be Straight Polarity or electrode negative. Also if the liner is cut to the wrong length or is getting used up you can cause it to sputter just by over bending your wrist. That can happen if the feed rolls are too loose as well. I like an oversized liner too. If you are running 035 FC, see if they have an 045 liner. Good luck!

 

[jjeff]

Flux core needs to be Straight Polarity or electrode negative. Also if the liner is cut to the wrong length or is getting used up you can cause it to sputter just by over bending your wrist. That can happen if the feed rolls are too loose as well. I like an oversized liner too. If you are running 035 FC, see if they have an 045 liner. Good luck

Yeah I need luck with this one, I was running 025 mig wire then 030 fc, before hand always does the same darn sputtering thing will check liner again if it's short crimped or short, didn't appear to be though if I looked at it right. I've changed out feed rollers and blocks to the specific wire I was using everytime.

 

[jjeff]

Since this non functional welder is currently driving me nuts, I put a hold to all my other hairbrain projects and pulled the cover on this Lincoln. All connections look pretty good and are secure with no corrosion or signs of arcing including the circuit board, capacitor, and transformer, visually inspected. Went to test the capacitor even though I'm unsure what it should read in terms of tolerances and my old multi meter batteries I left in it corroded everything in the meter. So spent some time trying to make it function again with electronic cleaner and emory paper to no avail. Was pretty pleased the 10lb roll of 035 FC was Lincoln brand inner shield and will use it in my mvp 210 soon. Also found a small roll of Hobart .030 FC wire I'll use it to test my Lincoln if i ever get to the root of the problem. Question for more knowledgeable folks, does that capacitor need to be discharged before hand? If so how? Yes it's unplugged. Thanks.

 

[CliffordK]

Any chance you know what values it should have? Do capacitors get worse over time meaning the length of time it functions somewhat ok consistently gets shorter? I think I have a multimeter that can test capacitance. However haven't done much electrical testing for almost 15 yrs though and then I wasn't very good or did testing on stuff consistently, I know enough to get me in trouble or keep me out of it. lol. Currently hoping it's not a circuit board.

Look for small capacitors that have a domed top (bad)
Large ones tend to spit out brown goop when they go bad.

My Powcon welder has one capacitor on the bottom with screw on terminals that like to come loose, generally causing it to stop welding and to be hard to turn it on and make it work.

Anyway, make sure connections are tight.

 

[jjeff]

Look for small capacitors that have a domed top (bad)
Large ones tend to spit out brown goop when they go bad.

My Powcon welder has one capacitor on the bottom with screw on terminals that like to come loose, generally causing it to stop welding and to be hard to turn it on and make it work.

Anyway, make sure connections are tight.

Thanks, it's a pretty big stand alone main capacitor, one thing Lincoln did on the circuit board is fully insulate and protect the circuits in it so fully testing every circuit is out of my wheel house. Im also thinking because of how this welder currently performs, heat is causing something to not work correctly. I'll look again for deformity and or electrolyte leaking from the main standalone capacitor. Im also aware if that capacitor is charged and if I'm not overly cautious I could receive a pretty serious shock so this is not one of my bull in a china shop projects. Finally curious if the transformer itself could cause these problems? Currently reading my 15 yr old industrial maintenance text book to figure out transformer testing procedures. Might end up acquiring a decent new multimeter cuz if I can figure out the problem of this welder with it it will pay for itself and then some.

 

[jjeff]

Brief update, visually re inspected capacitor, transformer, and circuit board all visually still look new. However after removing a ten pound spool of FC wire it appears after running welder at various wire feed speeds it visually appears the electric electrode drive motor only operates at one speed unloaded without it pulling wire off the spool. Going off memory on other welders on full wire speed that motor should be rotating much faster and it seems visually to be on one speed. So possibly the circuit board, wire feed rheostat, or maybe the wire drive motor? More testing to follow after I purchase a decent new multimeter.

 

[jjeff]

Lol said a few stern 4 letter words to this welder and all of a sudden the wire feed motor started working somewhat properly rotating at a much faster speed than previously, makes sense with how it was operating previously. I think I bought a lemon at least it was for a good cause, 10 yrs ago anyway.

 

[TripleS]

It may work better with the small spools of wire, the big roll may be to much on the spool motor.

 

[jjeff]

It may work better with the small spools of wire, the big roll may be to much on the spool motor.

Yeah I've tried 2-10 lb spools same thing every time. I now strongly feel there's something wrong with the wire feed mechanism either the rheostat, motor, or the circuit board, it was stuck on the same speed without pulling wire than it started working properly. I'll look into testing some of the wire feed components. Problem is wire feed issue is intermittent as I just recently discovered.

 

[5030]

Question for more knowledgeable folks, does that capacitor need to be discharged before hand? If so how? Yes it's unplugged. Thanks.

Sure does if it don't have a dropping resistor across the output terminals. Easiest way is to turn off the welder and disconnect the power plug and short across the terminals with a metal screwdriver.

You never want to fool with a charged (or it appears to be charged cap). I short all mine, resistor or not. A charged cap can burn you or even kill you if it's discharged in the wrong place on your body. They certainly go bad. Easiest way to tell is look at the metal can. If it's bulged or the top is bulged, it's shot. You can get a new one cheap on Amazonian. Just input the cap number in the Amazonian search bar. Lots of them on there and mostly oriential.

 

[jjeff]

Ok so I figured out what I'm going to do cuz I don't trust my welder troubleshooting skills or have adequate testing equipment i know how to use proficiently anyway, nor do I want to throw hundreds of dollars in parts at it hoping one will fix it. I can still put down an ok tack with it that's strong enough, so I'm going to swap it out for my newer Hobart 125 FC I have 500 miles away up north and don't use it much besides occasional thin sheet metal repairs. I will say after semi pulling that Lincoln welder apart it looks well made and when they function, work well and take abuse from previous experiences with that brand. I'm certain I got a fluke lemon one, and should have pursued professional repairs ten yrs ago when I won it at a charity auction, when I initially thought something wasn't quite right with it. I apologize for wasting some of your time with this thread cuz I was hoping someone had a backwoods hack to fix or troubleshoot it. Thanks for your insight.