Lincoln 140c flux core problems.

[jjef]

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 mig and currently have .035 flux core in it. Changed out feed rollers multiple times, 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 cuts back in almost like I'm trying to weld rusty or non prepped steel. Yeah my old Lincoln ran and worked flawless forever unfortunately gave it to a buddy. Suggestions what to test and look at are appreciated.

 

[jjef]

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 I put in it yrs ago was Lincoln brand inner shield and will use it in my mvp 210 soon after i convert it back dc- Cuz my 10lb roll of mig wire is almost gone and so is the tank. 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 I test it and does anyone know what acceptable readings? Yes it's unplugged. Thanks.

 

[SidecarFlip]

Check the capacitors, I believe you have a bad one.

 

[Lowensenf]

does that capacitor need to be discharged

YES
Alert! A good capacitor stores an electrical charge and may remain energized after power is removed. Before touching it or taking a measurement, a) turn all power OFF, b) use your multimeter to confirm that power is OFF and c) carefully discharge the capacitor by connecting a resistor across the leads.

How to Measure Capacitance with a Digital Multimeter | Fluke​

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