The 230 VAC Live input to the PCB is on pin A2, Neutral is pin A3. The Live on A2 also goes to the fixed contact ( 2 ) of the relay.
When energised, the moving contact of the relay ( 1 ) feeds the Live out on pin A1, which send power to the main transformer.
The resistance of the primary of this very small low-wattage transformer should be a few hundred Ohms, the 12v secondary a few tens of Ohms. There should be no continuity between the primary and the secondary. The circuit diagram shows only 4 pins - 2 primary, 2 secondary. Maybe the 5th pin is not used, or it could be a centre-tap on the primary for a possible 110v input version.
[ This transformer only runs the relay coil, and the yellow overtemperature LED. The power for the wirefeed motor comes from the rectified output of the main welding transformer.]
These small 12v transformers are available; search for "12v PCB transformer" or "12v encapsulated transformer". For example:
https://www.ebay.co.uk/itm/Transfor...1-5va-230v-AC-125ma-Piece-Housed/192100761297
https://www.ebay.co.uk/itm/Encapsul...hash=item2a1b163b77:m:mpFybSmUGjedKeMwvxSIPeQ
https://www.ebay.co.uk/itm/Encapsul...076606?hash=item1c41167afe:g:rj4AAOxyrrpThbi4
A new transformer may not have exactly the same pin layout and spacing as the original, you would have to adapt it with short extra wires.
When energised, the moving contact of the relay ( 1 ) feeds the Live out on pin A1, which send power to the main transformer.
The resistance of the primary of this very small low-wattage transformer should be a few hundred Ohms, the 12v secondary a few tens of Ohms. There should be no continuity between the primary and the secondary. The circuit diagram shows only 4 pins - 2 primary, 2 secondary. Maybe the 5th pin is not used, or it could be a centre-tap on the primary for a possible 110v input version.
[ This transformer only runs the relay coil, and the yellow overtemperature LED. The power for the wirefeed motor comes from the rectified output of the main welding transformer.]
These small 12v transformers are available; search for "12v PCB transformer" or "12v encapsulated transformer". For example:
https://www.ebay.co.uk/itm/Transfor...1-5va-230v-AC-125ma-Piece-Housed/192100761297
https://www.ebay.co.uk/itm/Encapsul...hash=item2a1b163b77:m:mpFybSmUGjedKeMwvxSIPeQ
https://www.ebay.co.uk/itm/Encapsul...076606?hash=item1c41167afe:g:rj4AAOxyrrpThbi4
A new transformer may not have exactly the same pin layout and spacing as the original, you would have to adapt it with short extra wires.
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