The resistance test with your meter now says that the primary of the small transformer is open-circuit.Just done that with the 20k setting on volt meter. The meter showed 0.L on the display before connection and stayed the same when connecting the J1 and JB .What does that mean now?
What do you think needs to be done now? So looks like it’s not as simple as changing the on/ off switch ?The resistance test with your meter now says that the primary of the small transformer is open-circuit.
The other test that I suggested, using the orange neon light in the On/Off switch, said that it was OK.
It is possible that even the burned-out primary coil, with melted copper and failed insulation, allows enough current to pass to light the neon lamp - which only needs a few microamps, so this method is probably not a reliable test.
I got the welder free.Looks like you need to go shopping…
new mains on off sw….( might need to be a Clark/Machinemart part..)
new transformer with the correct secondary voltage/current rating to fit the pcb
or a replacement pcb…. I think there’s a supplier in York that does replacement boards…around £80-90…( is the welder worth it? )
Could I do this with an electrical tester screwdriver ? Seems a bit riskyA simple test:
Can you gently prise the clear plastic case off the relay?
If not, drill, cut, or file a small hole in the top of the case. Plug the machine in, switch it on, then carefully ( ** AC mains present !! ** ) use a thin insulated screwdriver or a piece of stiff plastic rod or sleeving to push down on the metal plate at the top of the relay. This L-shaped plate will move down, and the leg will swing out to operate the contacts. The welder should then power-up, the wirefeed motor will run, and you should be able to strike an arc with the MIG wire onto a piece of scrap steel held in the "Earth" clamp !
If this works, especially at all 4 of the switched power settings, you'll know it is worth continuing with the troubleshooting and repair.
Better off with something that is insulated….a cocktail stick for example…reduces the risk of you getting shock….but the relay is only switching the transformers secondary so should be lo voltageCould I do this with an electrical tester screwdriver ? Seems a bit risky
Chopstick works really well - not the fancy stainless ones! But yes, that should fire up the welder, the motor's fed off the welding transformer from the look of it (goes via the board though, for wire speed control) so it should feed wire OK.Better off with something that is insulated….a cocktail stick for example…reduces the risk of you getting shock….but the relay is only switching the transformers secondary so should be lo voltage