Technical Wft is wrong with my mig welder?

I've been welding since the late 70's. Covered all the external basics.
I know how to run them but I'm not a fixer of machines, but maybe I can get this one to work well again with some guidance.

It's a Lincoln weld pak 155 that I've had since around 1998 or 2000. I weld with it at least alittle bit almost every day, some days it runs all day. I figure it's ran at close to 2000 lbs of wire thru it in those 20 some odd years. It really doesn't owe me anything.

The best way to describe it is the machine sounds like it has something inside of it and it wants out bad when welding. The machine randomly makes internal pounding noises and won't weld for shit, at least not consistently. Tacks sometimes bite in well and other times they get no grab at all, looks like a tack but falls right off.

It might be an easy fix, it might just be slap wore out.
Any help would be greatly appreciated.

 

Sometimes my temp dial ‘sticks’ between temp settings, turn dial back and forth and make sure it ‘clicks’ into the one you want.
Just a thought..

 

Take a look at the contactor. They can make pounding rattling vibrating noises when they are unhappy.

 

My old mig welder acted similar to what yours is doing and after talking with the local welding supply they convinced me the expense of repairing my 18 year old machine I would be better off replacing it. HRP

 

take it apart, look for the area that is getting hot, see if you can fix it or not.

 

A rodent is living in there and gets lit up every time you hit the trigger.

 

Diode would be my first check


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They can make noise when the wire advances because of a worn out liner.

 

I had similar problems with my machine. Took it apart to look at it. All big windings! I know nothing about that kind of electrical stuff. As Squirrel stated I saw things that looked like they got hot. Mostly at the connectors. Most were loose when I checked them. Tightened them up and it has been fine for quite a while now.
As with all electrical unplug it first. With all the windings in it be careful. They may store power even if unplugged. As I said above, I know nothing about that stuff.
Some time later while getting tips and liner at the welding supply. I mentioned what happened. They said that is a big percentage of the problems they encounter.

 

Please post what you find.

 

Sounds stupid, but have you checked the basics? How's the liner, and how old is the tip? I ask because I suffered through poor performance with mine till the tip finally froze up and I had to change it only to discover I had a new welder on my hands that actually welded again.
I ask because.....years ago a neighbour brought me a ford pickup with all the lights on the right side not working. After a day of troubleshooting and frustration, another neighbour who knows nothing about cars asked if I'd checked the bulbs...........and......you guessed it.

 

Open access panels and observe and listen to the "works" while triggering the torch on a test panel and while triggering and just running wire out. You may be able to see or hear where the problem is.

 

Guys when using a MIG welder , do not let the machine its self come in contact with what your welding ! Keep machine off a fender , floor etc.

 

Look at your contractors , could have a coil or connection that’s loose and movescwhen amps are going through it
Open it up and have a look see

 

Your machine does not have any mechanical contactors. Current is controlled by S. C. R. on your pc board, the clicking noise you hear is the gas solenoid . Take it apart look at the gas solenoid and make sure nothing is hitting the fan motor , and the drive motor is the only other moving part in that machine. You got your moneys worth from it just buy a new one . This time get a SP125. PS I worked for Lincoln for almost 40 years. keep what you can for parts gun, regulator, gas hose ext

 

there ya go^^^^^^^^good advise

 

Get on the phone and talk to these guys, they repair welders as well as PC boards. The board went out on my Miller xmt 304 and the cost of a new board was about $800. They fixed my old board for around $200 with a year warranty. No cost if your board doesn't need any work.
http://industrialelectronics.com

 

I opened it up and started at the beginning,
There wasn't much dust inside, a little but not much.
The voltage dial is ABCDE and when welding on the E setting is when the machine causes the most racket. I'm not sure this is the only proble but the E post is showing the most wear.
The heavy cable (top center) attaches directly to the E Post and you can see the itty bitty silver or tungsten contact on selector in position D.
Second pic shows the worn/dirty/burnt spot on the E post.
Now to figure out how to get it out and clean it.



Oh and today while my wife was giving me that "what's yours is mine" business today, I told her to keep it up because SHE needs a new welder too.

 

HRP said it best!

 

Well, you missed your opportunity to get her a new welder for Valentines day.

 

Nope, we do "Valentine's Day" all month!!
It's pretty nice.

Yep, I hear you.
Easier said than done sometimes. Especially times right after the holidays.
If I can get this one to do its job for a few more months it will be easy to do mid spring.

 

Now that you have the hood open, weld with it and have someone watch the welder. You might see sparks, or a puff of smoke to give you a clue. That is what I did.

 

Same welder about 20 years old had to replace the liner once from getting kinked, then replaced the whole gun and cable from just being worn out. The only problem I have had with mine is the tension arm for the feed rollers needed to have some modification to add more pressure.

 

I had a similar problem with my Miller Mig Welder, my problem we with the switch in the whip. The original switch was an open contact switch that started getting enough dust in it, the contacts were not always making or keeping the connection. The open switch could be cleaned, but within a couple of years of the first time, the contacts were shot. A new switch was around $20, but the new switches are now all sealed switches. The first new switch lasted about 3 months, and Miller replaced it with a new one. The replacement sealed switch lasted just over a year, so I bought 2 new switches. Installed one, and the other has been in the desk drawer for somewhere around 5 years now.

If you found a loose connection, file everything flat and tighten everything back up, it may work just fine. Gene

 

I have a Miller 140 thats 110 volt .At some point in time I ran a lead out of my garage and lit up the chicken house. The chickies water dish is heated , the golf cart charger was added later. I was having trouble sometimes welding ,other times it was fine. Took it local Miller dealer ,they plugged it in and said it was perfect . then they ask about power. When I told them about adding my Chicken Condo I had added to the garage circuit they said thats it .They were right ,

 

That's a good point - "dirty power" input.

I have been welding with it plugged into a new out let and new branch line.
It's single phase 220 but ran off a 3 phase panel. Could be not balanced on the phases.


I've tested it after cleaning the voltage selectors and it's much better.
The wire feed got total service too. The pressure tension arm is in need of replacement, but a small clamp is serving duty now. I also spotted the plastic wire roll's thickness was a bit smaller than the other rolls, a bit over 1/8". That would let it catch on the back pressure tension but not positive enough that it wouldn't bounce there every once in a while. So made a washer with holes away to take up the slop. While I was messing around I busted the ipm wire feed control so I put in a new potentiometer too.

So I guess I need to test it again on that new outlet and see if there's a dirty power problem.
In a little bit.

 

it may be a bad power transistor for the drive circuit board. the power transistor is remotely mounted in the cooling fan shroud. these power transistor are cheap.

 

You might look for a nut loose behind the trigger. When mine messes up this is often to blame.

 

Just for completeness and accuracy... they do not. However, capacitors do, and they are often "in circuit" with inductors (the coil windings you mentioned). So... still, be careful. Putting yourself in a circuit where a cap is still charged can be VERY dangerous, depending on the cap's ratings (capacitance in uF-- higher number is more energy storage in the cap; and voltage.)

/back to the welder repair portion of this thread

 

And as we all know ya gotta have a good ground not just at the work surface, but also look over the wire connection at the machine and at the clamp. Can't hurt while you're going over it all.