Welder Problem

I have a 110v Lincoln Weldpak HD flux core welder that has served me well for years. Just now I was welding a bracket and had it on for too long and the heat protection kicked on. This has happened before and once it cools off, it works fine.

This time though, when the thermo protection turned off, I have no wire feed. Both relays inside still click, but when I test the voltage where the wire feed motor plugs in, I get 0 volts.

Does anyone know a fix for this? Or at least a way to jump power to the feed motor to make sure the motor is still good?

THANKS!!

 

Is the cooling fan still running? I know on small millers the fan relay and gun are one and the same. I had to replace my fan awhile back just to get the welder to work again.

There is also a small fuse in most of the 110 units

 

The fan is running, and I think it will still strike an arc, though I havent actually tried. Seems to be a problem in the circuit board that the motor plugs into, but I would like to test that theory before I buy replacement parts.

 

I just went and checked and it will not strike an arc.

So at this point, the fan comes on, and the relays click when you pull the trigger, but thats it.

 

There is a white button on the back of the machine I believe, if not it was near the wire feed mechanism. It is a circuit breaker, it likely needs reset by pushing it in. I just got rid of mine, but I think that is what I had to do.

 

Like Willy301 said, check the white breaker next to the drive rolls. I am probably too new to this forum to make smart a$$ comments, but I am a welder by trade and have found that the easiest way to fix a Lincoln is to buy a Miller.

 

Well that made me laugh. Naw you fit in around here just fine.

 

I always thought that too but Miller has started selling some stuff that's almost as bad as Lincoln. They put circuit boards in that fail and they blame it on metallic dust like a welder is used in a hospital operating room. Then they don't sell parts for a 4 year old machine.

Everybody's trying to make things cheaper to increase profit margins as accountants take over businesses.

 

No circuit breaker on this one. Besides the fan works, I would think a breaker would shut the whole thing down.

 

Not sure if this is your model but way be close enough to help. On page 43 is a wiring diagram and it shows a thermal switch on the trigger circuit.

http://www.lincolnelectric.com/assets/ServiceNavigator/LINCOLN3/im759.pdf

 

Here is my welder http://www.lincolnelectric.com/assets/en_us/products/k2188-1/e7349.pdf

I know it has a thermoswitch, because I have had it shut off several times before. usually when this happens the relays wont click till it cools down. Currently the relays click, but thats about it.

 

Does anybody know where to get parts for these welders? Even the Lincoln site isnt very helpful. I would go get a Miller, but with $$$ being the way it is, I could only afford a HF welder, and that isnt going to happen!

 

Whereabouts in So-Cal are you? The shop I worked for (before retiring) services Lincoln, and I can find a local dealer for you if I knew where you're at.
Or go here and punch in your zip code for the nearest dealer:
http://www.lincolnelectric.com/en-us/Support/Locator/pages/locator.aspx?Country=US

 

Thanks for the link. I went and bought a new contactor for it since the one I had was pretty ugly. But it still doesnt work.

I checked the continuity of the switch, and it is good. Any other ideas guys?

 

I don't know anything about that welder..

On my early 1970s Miller, there is a relay bank of contact points made of silver. When you pull the trigger, these points all close to complete the circuit to get the arc. On mine, one pair of these points were used up, so I rebuilt the point surfaces with silver solder. Still works fine.

If you can see what's going on in there when you pull the trigger, maybe you can understand a bit on how it works, and what might be the problem....but it could be all electronic or hidden, etc

 

This is not a smart ass comment, but there is a thread right now just put up , that Grainger has NEW Millermatics 140's for like $332. This is the best welder in its class hands down, and used ones sell for a hundred dollars more than that, just a suggestion. They also have the best customer service in the world. maybe its time to upgrade. You can easily spend $300 fixing your old unit, and still have a Lincoln Weldpak. TR

 

You might have a wire tangle between the rolls and the gun liner, I had that mess up the feed before as well.

 

Thanks for the replies guys. I really dont have alot of $$$ to put into this one. I was hoping to fix it with the contactor, but that didnt work.

F&J - the bank of contacts is the contactor, I replaced that.

Also I bypassed the thermoswitch, but that didnt help. I checked continuity on the switches and they are all good too.

That leaves me with the circuit board. I dont know much about electronics, but other than the transformers, thats about all it could be.

Here is a wiring diagram on page F-1. Does anybody see a way to bypass the board? Even if I don't have wire speed control, that will do me for a while...

http://www.lincolnelectric.com/assets/servicenavigator-public/lincoln3/imt768.pdf

 

I do a lot of grinding in the garage and the dust did screw up my welder. I blew the thing out real good and it works now. Try cleaning it before you spend more money.

 

I will try blowing it out, hopefully that will do something. I found a part number for the circuit board, but I cant find a price on it.

Part number is S25351-21

 

I tried blowing it out with compressed air just to see if it would do anything, it didnt help. At this point I am just going to try to delete the circuit board.

I figure if I can get the trigger to engage the contactor, then get the contactor to turn on the wire feed and the transformer, then I can probably work with what I have. If that doesnt work, then I am just going to get another one. I will probably end up buying the same one I have, since its only $269 and has worked well for 10 years.

 

It really doesn't look like the internals are too awful complicated.

I would grab a multimeter and just chase it point by point. However it may be worthwhile to pull the board out and look for any popped capacitors or other burns. It may be just a single component on the board. It may be be something earlier on in the circuit causing trouble. If you can get to the components and probe it step by step, you should be able to narrow down where the break is.

 

I already pulled the board and checked for burns, etc. I traced all the wiring the best I could and it is all fine too. Thats why I think its part of the board. The problem is that I have no idea what I am looking at on the board. Wiring is easy, circuitry isnt...

 

Did you check the relay to make sure the contacts weren't burned out? If it's clicking that means the coil is good, but do you have power into the relay but not out to the feed motor?

 

That's too bad. It's always worth hoping for an obvious fix.

I didn't see your part number listed, but here is a site I found that does PCB fixes. Perhaps they will either be able to repair ( alot were under a 100 bucks) or can cross-reference it for you .

http://www.yorkelectronics.com/index.html

Unfortunately I had zero luck on the part number itself.

 

I found a place that had the board for $109. But thats half the cost of a new machine. So thats why I will probably go that way.

RickG - Ya I replaced the relay.

 

I'll take the broke one off your hands in that case...