Welding Tips and Tricks

Gday. Folks, as ive been building a new house the tools have been in storage for a few months.my mig has developed an intermittent problem where the gas would continue to flow after the trigger was released until the bottle was closed or the machine was turned off.....the torch itself also remained “live” arcing when ever in contact with the work piece....i fitted a new gas solenoid (tested it first!!) and still no joy. I thought it may be the gun, but when gun is removed from the machine, and gas is on along with power, gas still flows.....I’m no sparky so was after any ideas before i send it off for service. Could it be the power switch itself? Cheers for reading.

Darrin.

How about maybe you give us a chance to find the machine's schematics by providing manufacture & model?

Definitely odd to have power & gas flowing without wire moving as well.

The contactor and solenoid may be on a different circuit than the feeder motor.

If I were to guess, I'd say your contactor is sticking in the on position.

Or, again just a guess, the board is still sending signal to them after the switch is released.

Also possible that it’s a multi pole contractor and only some of them are stuck.

Franz© wrote:How about maybe you give us a chance to find the machine's schematics by providing manufacture & model?

Definitely odd to have power & gas flowing without wire moving as well.

Uni mig mini mig 180 KMM180.
Pretty generic model I’m guessing put out under numerous brands?? I cant find a schematic of the electrical system.....but even if i could i would not know what i was looking at!!!!!

Thanks for the replies Franz, Josh and Dave. It started doing it when the brother in law borrowed it, at the start I’m sure he said it was feeding wire as well when the trigger was not pulled, but now just gas and live torch.......still welds but freaking annoying.

does it have a 4t setting ?

tweake wrote:does it have a 4t setting ?

No, pretty basic unit mate.

Basic tapped transformer machine
http://www.metalworkingadvisor.com.au/r ... ig-welder/

https://www.manualslib.com/manual/78394 ... e=3#manual

PLAN B-
have you got a voltmeter and a mate who can fly safety man in case you get electrically connected?

If you do,
Put a voltmeter across the gas solonoid and see if it's energised or hung up .

While you're in there, turn the wire speed up and see if that motor's getting voltage too.

Post up pics of the inside of the machine so I can see what they built.

Plan C- call vendors in Oz who appear to be plentiful and ask for a wiring diagram.
Before you do, see if they glued one on the inside of the case.

Franz© wrote:Basic tapped transformer machine
http://www.metalworkingadvisor.com.au/r ... ig-welder/

https://www.manualslib.com/manual/78394 ... e=3#manual

PLAN B-
have you got a voltmeter and a mate who can fly safety man in case you get electrically connected?

If you do,
Put a voltmeter across the gas solonoid and see if it's energised or hung up .

While you're in there, turn the wire speed up and see if that motor's getting voltage too.

Post up pics of the inside of the machine so I can see what they built.

Plan C- call vendors in Oz who appear to be plentiful and ask for a wiring diagram.
Before you do, see if they glued one on the inside of the case.

Ill drag a voltmeter home from work tomorrow and check, this is the inside pics. Cheers.

Looks like it's built similar to an Ltec, current switching is on the primary side of the power transformer, so just for the hell of it, completely unplug the gun from the machine and turn the machine on to see if gas flows and the wire drive runs.
We'll call that Plan A - 1

Franz© wrote:Looks like it's built similar to an Ltec, current switching is on the primary side of the power transformer, so just for the hell of it, completely unplug the gun from the machine and turn the machine on to see if gas flows and the wire drive runs.
We'll call that Plan A - 1

Yep, gas still runs, no wire feeding, pretty sure when i switched it on a spark arc from the torch socket to the surrounding body of the welder......

At least we know the problem is not the gun or trigger switch.

Unplug the machine and closely examine the gun cable connector and wires running to it.
The big lump of brass should have 1 heavy wire and 2 light wires running to it.

I think the light wires plug into the machine wiring but I'm running from memory. They might be short pigtails from the brass going to the machine wiring, but I'm fairly sure they plug together.

You need to find those plugs and seperate them. Then plug the machine back in and see what happens.

Franz© wrote:At least we know the problem is not the gun or trigger switch.

Unplug the machine and closely examine the gun cable connector and wires running to it.
The big lump of brass should have 1 heavy wire and 2 light wires running to it.

I think the light wires plug into the machine wiring but I'm running from memory. They might be short pigtails from the brass going to the machine wiring, but I'm fairly sure they plug together.

You need to find those plugs and seperate them. Then plug the machine back in and see what happens.

Holy crap Franz, sounds like you’re talking me through disarming a bomb!!!!! These the two small wires you’re talking about mate??

Darrin wrote: this is the inside pics. Cheers.

to state the obvious is the dodgy spade terminal with two wires almost pulled out of it.
plus the joiner on the far right.
looks like its been played with at some stage.

i would just check where those wires go to.

also check the fuse on that sub board, can't tell in the pic if its a blown fuse or just a wound slow blow fuse.

tweake wrote:

Darrin wrote: this is the inside pics. Cheers.

to state the obvious is the dodgy spade terminal with two wires almost pulled out of it.
plus the joiner on the far right.
looks like its been played with at some stage.

i would just check where those wires go to.

also check the fuse on that sub board, can't tell in the pic if its a blown fuse or just a wound slow blow fuse.

Can I get translation on the BOLD text please?

Franz© wrote:

tweake wrote:

Darrin wrote: this is the inside pics. Cheers.

to state the obvious is the dodgy spade terminal with two wires almost pulled out of it.
plus the joiner on the far right.
looks like its been played with at some stage.

i would just check where those wires go to.

also check the fuse on that sub board, can't tell in the pic if its a blown fuse or just a wound slow blow fuse.

Can I get translation on the BOLD text please?

Ha!! Dodgy is “poor quality” and joiner would be “connector” i think Tweake’s. Talking about the crimp connector i used to fit the new solenoid, didn’t want to solder anything until i was sure. My electrical knowledge is pretty average and my electrical ability would be considered “dodgy” at best!!!

tweake wrote:

Darrin wrote: this is the inside pics. Cheers.

to state the obvious is the dodgy spade terminal with two wires almost pulled out of it.
plus the joiner on the far right.
looks like its been played with at some stage.

i would just check where those wires go to.

also check the fuse on that sub board, can't tell in the pic if its a blown fuse or just a wound slow blow fuse.

Spade terminal was me, i pulled the wires and made sure they were contacting, the red joiner on the wire to the right was for the new solenoid valve that ended up not being the issue....!!! The fuse is good, but pic makes it look like its blown.....

Check your gas pressure at the reg. If it is too high, it can force the solenoid to stay open. Possibly it got messed with during your move.

Mick

weldin mike 27 wrote:Check your gas pressure at the reg. If it is too high, it can force the solenoid to stay open. Possibly it got messed with during your move.

Mick

Cheers mate, even put on another reg and bottle, this thing is doing my head in!!!!

Darrin, just a thought, it will probably turn out to be useless, but I'm wondering 2 things.

Can you for experimental purpose substitute the original solonoid back into the machine (electrically only) and power it back up to see what happens?

Second thought, might try it first, swap the wires going to the solonoid A for B and see what happens when you power on.

Send it to me. It's clearly stuffed and I'll be happy to dispose of it for you

Franz© wrote:Darrin, just a thought, it will probably turn out to be useless, but I'm wondering 2 things.

Can you for experimental purpose substitute the original solonoid back into the machine (electrically only) and power it back up to see what happens?

Second thought, might try it first, swap the wires going to the solonoid A for B and see what happens when you power on.

Ill give that ago tomorrow mate, hospital day with the eldest child today so ill check it soon mate. Cheers.

weldin mike 27 wrote:Send it to me. It's clearly stuffed and I'll be happy to dispose of it for you

Ill give it a few more days then i may just douse it in petrol and throw a match to it!!!!

Oddly enough, I hear that a lot from the members of my facebook page.