need help with a welder feed problem

[BTL-A4]

I have a Chicago Electric Dual MIG welder 151 #55250 (or #06271 depending on what you read on the label).
I tried using it and the wire feed stays on when the power switch is flipped. In other words, I can't control the feed; it just feeds the wire. I can control the speed, though.

I thought it might be the trigger, but there doesn't seem to be any contact there when I close the case up.

Any ideas what could be wrong?

Pictures for your viewing pleasure:

 

[Jswain]

Does the MIG gun have a connector you can unplug and see if that stops the feed?

If it does then your trigger is definitely stuck and or shorted. If you have a multimeter it should be an easy fix to walk you through.

 

[BTL-A4]

Does the MIG gun have a connector you can unplug and see if that stops the feed?

If it does then your trigger is definitely stuck and or shorted. If you have a multimeter it should be an easy fix to walk you through.

It might. Is that the wire connected to the plate at the bottom? The 2 metal pieces shown are the plates that connect to complete the circuit, I think. They do not appear to make contact with the case closed.


I do have a multimeter.

I thought it could also be the switch on the machine. It's 240V, so I aint messin' with it plugged in.

 

[Jswain]

I mean at the welder end, is it hard wired or can you simply disconnect the connector?

If you can, disconnect the electrical connector from the MIG gun to the welder, set your multimeter on OHMs and touch the red lead from the connector to one of the pins from the MIG gun, and the black to the other.

Ideally it should read nothing (OL on most meters) and then when you hold the trigger on the gun it should go down to ~0.1-0.3 something around there.

If it is always reading ~0.1-0.3 then your switch is always making contact or the wiring inside the lead is shorted together. At that point I would remove the switch from the MIG gun & retest, then either replace the switch or run new wires from the switch to the plug

 

[ching0n]

can you jump the switch contact to rule out a sticking switch? If I recall this is 24DC circuit but would confirm w/volt meter if you don't want to chance it.

 

[BTL-A4]

It looks like it goes directly from the gun to the switches.


Could you clarify what I'm supposed to connect to what? Connect one probe to one wire from the gun and the other probe to the other wire from the gun? I should get nothing because they aren't supposed to be connected, right? If I pull the trigger, they connect and create resistance, correct?

The next step would be to check at the gun end, correct? Remove the switch and test both leads same as above?

After that, check the switch. See if the wires are touching or otherwise not connected correctly?

Electrical is not my strong suit, so forgive my ignorance.

 

[Jswain]

Yes, pretty much. Disconnect them from welder & hook your multimeter leads into the 2 wires for the MIG gun trigger.

As you said, you should get nothing(normally open) then when you pull the trigger it should read ~.02.

If that test is good you have another issue, if it is bad then you know the problem is either the wires in the gun or the switch. So isolated again by removing the switch and check them both individually

 

[The Cobbler]

something is closing the circuit to the wire feed . my Princess Auto mig welder has a piss poor set up for trigger switch. I'd look there first .

 

[BTL-A4]

When I pull the trigger it reads about 2 Ohms. It bounces around all over (0-80) if I hold the leads there longer than a second.

I'm not sure how to check the switch because one of the wires from the gun goes to power and the other goes to the circuit board.

The wires on the switch all look good. How would I check the switch?

 

[BTL-A4]

something is closing the circuit to the wire feed . my Princess Auto mig welder has a piss poor set up for trigger switch. I'd look there first .

I checked it again. Nothing seems to be connecting when I close up the case.

 

[The Cobbler]

can you take off the wires from the switch and check

 

[Old Man Roger]

Basically if you unplug the wires in the red circle and it stops the feed, then your trigger is likely the problem.

Make sure the trigger isn’t being activate by the case itself.

 

[BTL-A4]

can you take off the wires from the switch and check

Yes. What should I check?

 

[The Cobbler]

check if theres continuous continuity with the switch depressed and released

 

[BTL-A4]

check if theres continuous continuity with the switch depressed and released

Continuity between what? I checked between the two wires from the trigger switch and there's continuity when the trigger is pushed and none when released.

 

[The Cobbler]

between the 2 switch contact . this will tell you if the switch is stuck closed or not.

 

[BTL-A4]

between the 2 switch contact . this will tell you if the switch is stuck closed or not.

You don't mean the power switch, do you? I edited my answer in post #15.

 

[The Cobbler]

I mean the switch in the gun that turns on the feed for the wire. I just re read your post #15 and you've already done that

 

[BTL-A4]

I looked at the wiring diagram and could switching the wires from the trigger work? My wires might be switched. One from the gun goes to the rectifier, the other goes to the circuit board, but it might be that they need to be reversed. Does it matter which wire is connected to what?

 

[The Cobbler]

doubtful. all the switch is doing is closing the circuit

 

[BTL-A4]

That's what I thought. It might be something on the circuit board, but I can't figure out how to get it off and I can't see the back of it; it has a cover over the board. From what I CAN see, there doesn't appear to be any damage.

 

[The Cobbler]

my electronics buddy would be looking for leaking and bulged capacitors. sometimes components will leak onto the board & be conductive enough to basically short circuit

 

[Jswain]

If you disconnect the wires from the trigger and turn on the unit then I'm guessing it starts feeding wire then eh?

Perhaps the drive motor itself for the wire feed is hooped

 

[whateg01]

It's 240V, so I aint messin' with it plugged in.

If you are in the States, that's really only 120 to ground

 

[whateg01]

If you disconnect the wires from the trigger and turn on the unit then I'm guessing it starts feeding wire then eh?

Perhaps the drive motor itself for the wire feed is hooped

The motor only spins if it's getting voltage

 

[Old Man Roger]

Basically if you unplug the wires in the red circle and it stops the feed, then your trigger is likely the problem.

Make sure the trigger isn’t being activate by the case itself.

If you’ve done this and the feed is still going, disconnect those same two wires from the other end. If the feed stops, then you might have a short between there and the trigger.

If it continues to feed, then the problem is in between the feed motor and the power source. Process of elimination.

 

[seber]

I'm not familiar with that particular unit but I am going to make an assumption that there is a relay involved. Relays tend to stick when they get old.

 

[jonesg]

I'm not familiar with that particular unit but I am going to make an assumption that there is a relay involved. Relays tend to stick when they get old.

theres a relay for the gas valve, it might also power the spool motor.

with the newer welder technology being so much better I'd drop kick this one, any excuse for a new one.

 

[BTL-A4]

UPDATE:

I gave it back to my buddy. I'm tired of wasting time on this POS. I'm looking at an Eastwood welder (#33980, $550). It should suit my needs. Does anyone know if they ever go on sale?