miller thunderbolt noise?

[65-408]

I have an old miller thunderbolt AC/DC machine. It is considerably more noisy when running on AC than on DC, is this normal?

thanks

[cruizer]

Its just a noisy machine. you can and should grease the internal shunts and center screw though.

[wayne50]

I have a 5+ year old Hobart AC/DC. If I remember correctly, the manual says you may need to adjust the shunt screws for too much vibration and noise. I had the opposite problem. My crank was too hard to turn and I loosened each shunt adj. screw about a quarter turn. If your machine has the crank adjustment and it seems real easy to turn, you may need to tighten the shunt screws just a fraction.