ReplyFind the spark gap assembly and look at it and listen to it as you fire the torch in the air.
First there should be a spark. Double check the HF control switch and make sure it is not set to off.
If no spark in start, switch to continuous. If still no spark get an ohm meter and measure across the spark gap points.
Should read around 6000 ohms. If it read near zero the big square black capacitor is most likely shorted.
Disconnect the cap and the point should fire with a soft buzz. Replace cap and should come back to life.
If points a sparking in all tests. We look for two different types of arcs. One is a soft buzz like a neon sign
and the other is a sharp crackle. Sharp crackle is what we want to hear. The soft buzz is an open capacitor.
If you have a good sounding arc but torch will not fire and will scratch start. use an ohmmeter and measure between the torch
and the welder case. Should see and capacitor. if zero ohms there is a short to the case and the HF is bypassing the torch and going to the case. If we have spark in cont. and no spark in start. you will need to look at CR1 the voltage sensing relay.
It may have failed. It is obsolete from Miller and it will have to be sent to a pcb repair place for repair.
Also one of the control pcbs may have failed also and same problem with it.
Tell us what you find. we will go from there.
