Hobart Handler 120 welds poorly

[jsee238]

Arc starts fine but voltage jumps in and out intermittently. almost as if some one is fisically turning switch on and off very rapidly. Welder will make a bead that looks like you welded with very low amperage. I have replaced both diods.

[Jake_SS]

Do you have wire speed control, is the gun feeding OK, contact tip, why did you replace diodes, did they test faulty? Only 2? More info needed
Cheers

[Tux_Rules]

I have this problem when I don't take the time to clean the area to be welded. Worked on my car exhaust the other day, just a quick and dirty fix, and it looked horrible. Same thing, starts fine, but cut in and out, bad looking weld. The metal was quite rusty. Clean the weld area good and make sure the ground area is clean as well. Just my .02.

[scribbles]

How long have you used the welder? Were you able to get good weld with it before? Sounds like your contact tip is dirty/two big, or speed two low, or shielding gas is low empty.

[jsee238]

thanks for the replies! yes i do have wire speed control, and its working as it should. The tip in new. I took an ohm meeter reading through both diodes and yes one was bad, so i chnged both to be safe. when i first bought the welder worked fine. i turned it on after it sat for about two weeks and could not get any arch. i replaced both diodes an it started working like i siad before. i checked all wires surronding for shorts to ground or bare places thing the soldering gun hit one. all check ok. everything with the gun is ok. i weld at work with on a daily basis mig/stick, also pipe/structual certified by state of ky. i never weld without wire brushing any area with a wire wheel on a grinder because arch tends to wonder on dirty/rusty metal im welding new steel plate i cut on our band saw at work. thanks guys