Help with MigMate 130 Turbo !

[thewalkertron]

Hi everyone, bought a secondhand old welder (as above) middle of last year for welding up my old beetle, worked a treat since I've had it but it's definitely a tired old thing. Had about 2 week off welding and come back to it yesterday, it powers up and the fan kicks in, but when you pull the trigger on the torch not a thing clicks to say anything is working. Had both panels off to see if anything looks blown or loose, gave all the wires a good pull n prod but no luck. Took the torch apart and same thing there everything looks to be in working order, just old lol. I've searched this forum for something similar but I haven't come across anything like this? I'm no electrical expert but more than happy to have a play with it, would anyone know where to start?

 

[eddie49]

Hello and welcome to the Forum.
The most common reason for MigMate welders to suffer the type of failure that you are seeing is that the small auxiliary transformer mounted on the printed circuit board fails with an open-circuit primary.
This transformer has a 230-volt mains primary which is on when the welder is initially switched on, and a 12-volt secondary. The secondary AC voltage is rectified to DC, then switched by the torch trigger to activate a relay, the contacts of which send mains power to the welding transformer.
With power off and the machine unplugged, you could check the continuity of the primary and secondary winding with an Ohmmeter. Expect about 500 Ohms to 3k Ohms for the primary, and 200 Ohms for the secondary.
If you are confident working on live mains equipment, you could check whether there is any secondary output voltage from this small transformer when the welder is powered on.

 

[pedrobedro]

Hi everyone, bought a secondhand old welder (as above) middle of last year for welding up my old beetle, worked a treat since I've had it but it's definitely a tired old thing.

I had an Autoplus 130 and a friend of mine bought the Migmate 130 at the same time. He still uses his it must be 40 years old now Mine didn't take long to trip when it reached the end of the duty cycle, could it be the trip gone on yours ?

 

[thewalkertron]

Hello and welcome to the Forum.
The most common reason for MigMate welders to suffer the type of failure that you are seeing is that the small auxiliary transformer mounted on the printed circuit board fails with an open-circuit primary.
This transformer has a 230-volt mains primary which is on when the welder is initially switched on, and a 12-volt secondary. The secondary AC voltage is rectified to DC, then switched by the torch trigger to activate a relay, the contacts of which send mains power to the welding transformer.
With power off and the machine unplugged, you could check the continuity of the primary and secondary winding with an Ohmmeter. Expect about 500 Ohms to 3k Ohms for the primary, and 200 Ohms for the secondary.
If you are confident working on live mains equipment, you could check whether there is any secondary output voltage from this small transformer when the welder is powered on.

Thanks for the reply Eddie, I'm a bit of a novice with stuff like this, I'm looking at the small circuit board and thinking these 2 metal plate looking things are what you're referring to? Forgive my lack of knowledge, trying my best to figure out if I can keep the old girl going!

 

[thewalkertron]

I had an Autoplus 130 and a friend of mine bought the Migmate 130 at the same time. He still uses his it must be 40 years old now Mine didn't take long to trip when it reached the end of the duty cycle, could it be the trip gone on yours ?

Thanks for the reply, how could I find out if it has tripped? But yes it's an old thing alright, would love to keep it going though, it's lasted this long!

 

[bricol]

My similar machine used to play up due to the connections made to those nice thick red insulated wires from the main transformer - remaking those sorted it.

Bought it when I was 19 . . . in 1989 - and that's the only repair I ever made to it - never even changed the liner, or any tips (after the first 20 odd I welded up learning to attach bits of metal to other bits of metal).

 

[eddie49]

The aluminium fins are a heatsink, to cool the power transistor that is riveted to it. The small transformer is the rectangular black plastic block.
To check the continuity of the transformer windings, you will need a multimeter, set to the 2k or 20k Resistance range. Switch off and unplug the welder. Unplug the green multi-pin plug from the circuit board. You may have to lever it out with a small screwdriver. It will only plug back in one way round.
Then label the three single wires with push-on tags before disconnecting them. The blue wire nearest to the green plug should be labelled "4", the thin black next to it is "3", and the slightly thicker black wire at the top is "7". These numbers correspond to the wiring diagram on Page 31 of the manual here:

https://www.qsl.net/g4usp/SIP%20MIGMATE%20100/Migmate%20100%20120.pdf

The primary winding resistance can be checked between the pins for wires 4 and 3 ( blue and thin - lower - black ). If the transformer is OK, it should be between 500 and 3k Ohms. If the primary has burnt out - a common problem - the meter will show open circuit - infinity Ohms.

 

[mw8]

Hi I had similar problem and turn out was one of the white setting switches was not fully push to to on \ off side

 

[eddie49]

Hi I had similar problem and turn out was one of the white setting switches was not fully push to to on \ off side

Yes, the power selector switches can fail, burn inside or become open-circuit.
I was going for a failed small transformer on the PCB based on the OP saying that he could not hear a click when pressing the trigger.

 

[OldMig130]

I have had the small transformer on the circuit board of my sip 130 migmate fail a couple of times, first time I get a new circuit board, didn't know what it was but the new board fixed it, pretty sure it was the transformer, 2nd time I couldn't get a new board so unsoldered the output terminals of the transformer and put an ohmeter across them to confirm open circuit, which it was. The part number is SIP 11313 TRANSFORMER FOR 10008/20508/109, likely the same one on yours but worth checking. Seems to still be available:

SIP 11313 Transformer FOR 10008/20508/109

SIP 11313 Transformer FOR 10008/20508/109

www.sipuk.co.uk