You really need to check the diodes and transformer output when your dad's finished using his multimeter.
The motor per-se won't prevent a spark happening. Going by the circuit diagram if the transformer/rectifiers are faulty neither the motor nor the arc will work.
You really need to check the diodes and transformer output when your dad's finished using his multimeter.
............ if the diodes have gone and there is power getting to the main welding transformer it should be buzzing very badly when you pull the trigger,..........
very true, there are lots of possibilities without ant actual testsIf a shorted diode has since burnt itself out to an open circuit the transformer shouldn't buzz.