Miller bobcat

[randy483]

I have a miller bobcat 225g that will only weld on the lowest voltage setting. Have power to the outlets. Checked fuses. Have voltage on only one brush.checked brushes. Their good. Not stuck. Any ideas what is wrong? How do i check the slip rings?

[Bls repair]

Check contacts on switch?

[randy483]

Yes

[randy483]

Cleaned slip rings also

[randy483]

Should there b voltage on both brushes?

[randy483]

Any ideas?

[Aeronca41]

Only one brush should have voltage-the other one is grounded, at least on the randomly chosen manual I looked at. Please post your Ser no. so we can look up the right diagrams.

[Aeronca41]

Was it working for you before or did you just acquire the machine? By "power to the outlets" do you mean you can plug in a grinder and it works, or only that you measured voltage there? Have you tried both AC & DC welding on various positions of the current selector switch and fine current adjust control? Checked contacts on both current range and polarity switches? Assume you are attempting to stick weld. Output cables connected to the left and middle terminals? What is your level of skill and comfort with measuring voltages for further troubleshooting with the machine running? Safety is paramount. If so, does the voltage at the brush change when you vary the fine current control? If one of the gurus sees this thread they may have knowledge of a common problem with this machine-I am not a welder expert but generally can fix most things electrical.

Don't know your level of expertise, not trying to question your intellect, just trying to cover as many bases as my limited knowledge can think of to start.

[1997CST]

The big corn cob resistor along the top with the band on it. Take the band off. Clean the rust off both connections. your problem is solved.

[randy483]

Thanks 1997cst i will try that

[randy483]

Will get serial # asap