I have a Miller Big 40 welder, serial # HD71116, that was welding perfectly about a month ago. It isn't used often. I tried to weld with it today and it would not weld or run A/C tools from the outlet. The motor runs fine and the welder/generator seems to be running but produces no current. I have a wiring schematic and physical drawing of the welder. What could be the problem and what should I check first? Thanks for any help you can provide.
Open inspection door,which also the fine tuner knob is ,there's a 2x4 size circut board that snaps out with little force to remove,this is the voltage regulator board,look for 4700 ohm resisitor burnt into,tv tech can fix or order new board at $227.00 what i paid.
Check to make sure that the throttle is reving up. I have the same machine and have had the same problem, the short fix I used was bailing wire on the carb. LOL. Turned out to be my idle solenoid.
My machine did the same thing. Used it on a Friday, no output on a Saturday. Nothing to do with idle speed, engine runs fine, pull throttle manually as its diesel. Would rectifier cause this in both the AC outlet and the welder output, or should I rule that out?
The SR1 bridge rectifier might cause this. As I said before, check to make sure the brushes are making good contact and the slip rings are clean. Also check R3 resistor and make sure the slide is making contact on the resistor. If all of that is good then it's time to check the generator windings.
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The first place I would look is to check the brushes that ride on the slip rings and make sure that they are making good contact with the slip rings and clean the slip rings with either an armature stone or some scotch brite. If the brushes aren't making contact then there is no output.
Ok boy your welder have a riostathic control check contacts of your control maybe have dirt or grease
Not familular with this unit, however, check the power rating of your tools against the rating of the outlet, some generators will cope with lighting only and will fuse if a power tool is used under load ,
lets know the outcome of this first then we can move on....................
I understand, but when the outlet blows it can cause the AC/DC circuitry within the unit to blow causing a diode to go down,as I said, I'm not familular with this unit but base my thinking on other units I have used in the UK, go with the simple first before you start striping down the machine and ending up with a bigger problem, you understand , Is the arc AC and DC or just DC ? with the AC on the outlet/s ? assuming it is AC/DC then check the bank of diodes usualy 8 - 10 mounted on large heat sinks, being extreamly careful, check for voltage input if there is power then check the ouput, no output or very little output indicates that one or more of the diodes have gone down, you can expect more than one. Make sure of your safety before checking these.
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Thanks but that does not appear to be the problem because the welder will not supply the stinger with current for welding either.
I appreciate your input and if you have anyother ideas I would welcome them.
Thanks!
Thank you for your help. The welder is DC only with an AC outlet. It is a pipeline welder roughly equivalent to a Lincoln SA-200. I'll let you know what I find after I have tried your suggestions. Again, thanks a lot for your help.
The welder works but the arc is so week that it only welds on high rang.
I have a Big 40 also, serial #HE772374. I was told I need a new armature. Does anyone know where I can get a used one?
wont weld on dc current
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