Hello Solderer,
I’ve had this issue a number of times on my Smashweld 185. The welder remains still alive and humming but there is no wire feed. Remove the plug from the socket. Bear in mind that capacitors can retain charge despite the machine being switched off. There is a small circuit board behind the wire speed knob. Remove the right side panel for access. Slide out the circuit board, you don’t need to undo anything, carefully use pliers on a section of unprinted board if necessary. Take a pic of the board to ensure that you can replace wires in the correct positions later. Pull the two clips from the connector on the left and it will come apart easily (the shapes of the upper and lower sections indicate the orientation, use pliers when replacing to keep the clips pointing the right way - almost impossible with fingers). Remove the red, green and two black wires from the top. On reassembly it doesn’t matter which way the two black ones go on. Undo the small screws to remove the red, white and green wires. The circuit board is now free.
I have experienced three issues with this board, all easily fixed. Your user name suggests some expertise here.
1. Diodes: There are four. Just replace the lot. They’re about $2 each AUD. Make sure you orient them the same way - they’re one directional! Markings on the circuit board match the band on the diode for orientation.
2. Transistor: This is centrally located. Despite appearances, it also only mounts in one way. Undo both screws before desoldering. Also only a few $.
3. Relays: If the circuit board rattles, it is likely that one of the two relays has fallen apart. It may also show some physical damage. These are around $9 AUD. Replace both if these are the issue and keep the good one for an emergency spare.
Do the rattle test first. Otherwise replace the diodes and check if it functions before replacing the transistor or relays. I keep spares of all these components now. It is much easier than having to wander off to your electrical components store in the middle of a job, especially if it an 80 km trip! It is worth taking the board with you when sourcing components to ensure that replacement parts are correctly identified.
Simply restore the wiring, check against the pic you took and slide the board back in, ensuring that no wiring will be trapped when reattaching the side panel. Voila! Think about what you were doing when the wire feed stopped. Was the tension adjustment on the feeder screwed down too much? Is the tip correct/not worn too much? If the wire is melting onto the tip it could be low feed rate / excessive voltage, tip wear, junk or wear in the core of the trigger line, etc. if the wire jams excessively it will overload the circuit board described eventually. Make sure you don’t keep pressing the trigger, hoping it will somehow fix itself. Address any feed issues promptly. My MIG gets a fair bit of work and I’ve had to effect these repairs 4-5 times since buying it 15+ years ago. Doing it yourself is far cheaper and quicker, but be cognisant of the potential risks of working on electrical equipment and only do this if you can do so safely.
