lincoln welder can't turn knob

   / lincoln welder can't turn knob #1  

buckeyefarmer

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Years ago I bought a Lincoln AC welder for my dad. Last time he was using it he told me he can't turn the Voltage adjust knob, it's like it's seized up. Anyone have this happen? I figure for repair cost it's probably better to just get a new welder. He uses this a good bit to repair farm equipment.
 

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   / lincoln welder can't turn knob #2  
I'm experienced and trained in electronics and I wouldn't want to have to wire in a new "heat" switch in a Lincoln Tombstone. I'd be opening that puppy up and trying to figure what has happened to freeze up the switch and try to free it up.

I'm talking about the amperage switch. If you have smaller hands, patience, soldering skill and time on your hands then why not give it a whorl. Those welders are pretty bullet proof and if it could be repaired for half or less the price of a new one it would certainly be worth it to have it fixed at an authorized Lincoln service center if you aren't up to it.

My Lincoln Weld Pak 100 MIG is down with fried diodes and I will replace them my self for about $150 in parts. I'd still do it if it cost $300 in parts but that would be about the limit. I abused the dickens out of that MIG, ignoring duty cycle and welding till it went into thermal shut down again and again and again. It has lasted over 15 years before anything went wrong. So, a little of my time and $150 and I'll be making sparks again.

Pat
 
   / lincoln welder can't turn knob #3  
Heck, take it apart first. I tore my new (used) one down to clean it up and get the power cord secured properly so it wouldn't chafe on the sheet metal (anymore...). It's only a few screws. You'll figure it out.

-Dave
 
   / lincoln welder can't turn knob #4  
Get the code number off of the welder and see if you can get an exploded parts view from a distributor, or Lincoln's website. It may just be a bolt on tapped switch that's easier to replace than you think.
 
   / lincoln welder can't turn knob #5  
I had one that did the very same thing. Got harder and harder to turn the knob in certain positions. I attributed it to using some of the voltage settings much more often than others, the cheaper design of using a switch in the first place vs. the old rotary windings which gave you a more infinite amperage selection and the use of aluminum instead of copper in the construction. I sold mine after I found an older unit at an auction and have been happy ever since.
 
   / lincoln welder can't turn knob #6  
I realize this is a welder your father has had for some time but maybe hasn't used in a while. I had an older friend describe similar symptoms with his old DC Lincoln and wanted me to look at it for him. Turned out he was forgetting that the knob had to be pulled out then turned. The knob was really hard to turn even doing that and I cleaned the contacts and that helped as well. I don't know if the AC units have the same type knob or if this could be the problem but felt it may be worth mentioning.
 
   / lincoln welder can't turn knob #7  
Both of my Lincoln AC, AC/DC welder have the same issue of the hard to turn knob. I ended up turning it with pliers and it didn't break the plastic knob - can't guarantee that yours won't break.

Anyway, the knob is still hard to turn. It would seem that it would loosen up with a few wrench-aided turns but no.

Taking it apart to see what is up as others have said is the best solution. Please share your fix with this lazy poster.
 
   / lincoln welder can't turn knob #8  
Buckeyefarmer:

I have a 30 plus year old 180amp tombstone that had exactly the same problem. Switch was really sticky to turn, in fact all but froze up.
I took it the cover off and checked the switch. A little WD40, and patience working the switch and the contacts but particularly the shaft. The switch uses plastic moving parts and they get gummed up over the years. It causes excesive wear.
The WD40 cleans the gum away, make sure to clean it off the contacts after you spray.
I've been in the electronics business for 40 plus years. Fixed everything from big electrical contactors and motors to microwave gear, so I'm not intimiadated by anything electrical.
As far as a permanent fix, the switch will disassemble so you can replace the worn parts causing you the problem. You won't have to rewire a new switch. The only down side is that you won't be able to get the parts you need separately, you'll have to buy a new switch.
Sorry I didn't take any pictures when I did this, I was needing the welder for a project and was in a bit of a hurry. Just remember this ain't rocket science.
Hope this helps, take pictures so others can see as well.

Cheers.
Glenn.
 
   / lincoln welder can't turn knob #9  
As long as you of he did not turn the switch while welding, You can free it up. Just take a Scotchbrite pad to the inside conductor plates and finnish with a little dab of grease. Should last another 20 yrs. It does suck to replace the giant sized voltage adjustment on that unit but it's not too expensive. good luck.
 
   / lincoln welder can't turn knob
  • Thread Starter
#10  
thanks, will take a look at it when I can. not something you want to do when it's 100 degrees outside.
 
 
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