Snap on Arcos Lincoln mini mig 180c not working

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Just bought this non runner machine for spares for my own which happens to be the Cebora version of it and it’s actually in better condition than mine. I needed a main ‘power selection’ switch as my number seven isn’t working but I’m tempted to get the newly bought Lincoln one working first to see what was wrong with it.

The previous owner said it just stopped so that could be anything. There is nothing happening at the torch end so I’ve tested it manually by pressing the button on the contactor and with that have power in all seven switch positions at the transformer end inc testing the voltage increments but no solenoid click or movement in the ‘contactor’.
The torch is a vintage std Esab one from decades ago and tested as working but the gas solenoid and the wire feed motor are not getting any signal to activate.
Can anyone tell me what the small transformer directly under the multi power switch does and also what voltage does the circuit board run at?

 

[eddie49]

I think this diagram applies:

Snap on minimig 180c won't start - got nothing

Hi, I was hoping for a little enlightenment regading my welder. It's an old (20ish years) Snap On Minimig 180C ( i believe its an acros Lincoln from reading on this forum). Problem: When i turn it on i get nothing, the transformer seems fine, i have tested its output against the wiring...

www.mig-welding.co.uk

and actually the fault description of that thread is similar to yours!

The small transformer has two secondaries. One is 42v AC and it runs the gas valve and the contactor. Rather an odd voltage for a contactor operating coil? You could check if the contactor coil is printed or tagged with that voltage.
The other secondary is 17 volts, it feeds the circuit board, and probably gets rectified and smoothed there, giving about 24v DC. According to the thread linked above, there is a fuse on the PCB, and also two relays. One relay may be to drive or brake the wirefeed motor, and the other will probably switch the 42v to the contactor. I guess that both should operate when you press the torch trigger switch - you could confirm that by looking at your own working Cebora version of the welder.

 

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That’s an informative start to be getting on with. I’ll have a look over the next day or two. Cheers Eddie49

 

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So far I’ve played about cleaning the crap off the wiring to identify what goes where and which printed id it is. It’s been very satisfying just doing that atm. I’m also not getting any power to the circuit board so it’s narrowing down a bit now. I’ve to get my head round that small transformer that feeds the board and the other things as I’m guessing summat ain’t right at that point or earlier on route.