Miller 130 sputters

[scooby]

Cannot get a smooth (buzz) arc. Have tried all kinds of wire speed & heat setting combinations. Good electrical connections throughout welding circuit. Metal (mild steel) shiny & clean. Co2 gas with flow set at 20 CFH. Have also tried varying gas flow rate. Does this machine use a full wave rectifier to convert AC to DC? Could one or more diodes be defective? Does anyone have a schematic diagram that shows voltage readings throughout the machine? All comments & suggestions welcome. Tks.............Scoob

[walker]

Generally speaking, the ground clamp connection is always suspect. Feel it after welding for a minute or two of welding, if it is hot it is bad. Disassemble, sand, reassemble. Next biggest fault point is probably the liner. Pull it out and look for kinks, blow it out, or just replace it. Then look at the contact tip, or replace it. Then reset wire drive roll tension. Those few things cure almost all MIG woes.