Murex 240 popping 1amp fuse

[Wiseweld]

My old but reliable murex 240 mig welder started up with fan whirring and then fan slowly died. Located two fuses 1 1amp and 1 3.5amp 1amp keeps blowing as soon as plugged in. What can I start disconnecting to isolate what is causing the short? Wire feed off main board unplugged still blowing. How do I test the windings. Maybe they finally given up.
Many thanks Paul

 

[TryingToWeld]

The 1 amp fuse won't be protecting anything high current! So ignore the heavy current stuff and have a poke around the pcb. Look for burnt components etc.

If you have meter, WITH THE WELDER UNPLUGGED, measure the resistance from the fuse holder to ground/earth. If it's very low (less than 250 ohms) try unplugging things an see it if it suddenly jumps up.

 

[Dave-sparks]

Have you checked the fan? If it made a noise and slowly died it suggests it's probably broken, and it is the kind of thing you might expect to be fused at 1Amp.

If not then fan then trace the wire outgoing from the fuse goes, it looks like the wires are numbered at their ends so you should be relatively easy to trace.

 

[Wiseweld]

The 1 amp fuse won't be protecting anything high current! So ignore the heavy current stuff and have a poke around the pcb. Look for burnt components etc.

If you have meter, WITH THE WELDER UNPLUGGED, measure the resistance from the fuse holder to ground/earth. If it's very low (less than 250 ohms) try unplugging things an see it if it suddenly jumps up.

Thank you. will play around in the daylight tomorrow.

 

[Wiseweld]

Have you checked the fan? If it made a noise and slowly died it suggests it's probably broken, and it is the kind of thing you might expect to be fused at 1Amp.

If not then fan then trace the wire outgoing from the fuse goes, it looks like the wires are numbered at their ends so you should be relatively easy to trace.

Yes they have little bird rings on them. Fifty years of dust but I was. Gonna disconnect fan next. That would be an easy fix. Machine has. Been like an old Toyota just keeps going. Sad to have to strip for parts. So smooth and powerful for a single phase.