Miller aerowave not working, amps set to HIGH value and cannot change

My coworker has a Miller Aerowave TIG welder. It did work
previously. Now it does not work. The amps display shows a very HIGH
number that cannot be adjusted with amperage knob. It does weld at
that extremely high setting and melts welding rods.
I have some pictures of the welder and board LEDs at:
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Would anyone suggest a solution? Also does anyone know a good welder
repair shop on the Chicago area? Thanks
Reply to
Ignoramus19737
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Just a stab in the dark.
Is the current set by a potentiometer?
If one end has gone open it could be pulled high or low causing the welder to think you want full current.
If you're confident of not electrocuting yourself, try to measure the voltage on the wiper of the potentiometer as you wind it up and down and see if it sweeps up and down.
I'm not familiar with high end welders and can't believe how much electronics there are inside that one!
Reply to
nub12
Might be something related to the foot-switch? Not sure how they work together with the knob settings...
Have you downloaded the owners manual:
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Looks like a nightmare inside without the full tech manual to guide you around. Much more complicated than the Millermatic I'm trying to repair...
I see you found the Miller Forum. Nobody has jumped forward to help you so far but it hasn't been up long. You might get a tech manual from that site if you ask nicely :)
Reply to
Leon Fisk
Interesting that there are separate controls for current EN and EP. have yo u tried both settings? I agree that you want to be looking for an open or s hort in the control pot or perhaps in the pedal wiring.
If the voltage doesn't change on the pot wiper, try disconnecting the wire from the pot and see if it changes then. If it doesn't, the problem's in th e pot (assuming the's voltage getting to the pot and the other side of the pot is grounded (or at least has a different voltage) - the wiper terminal voltage should be able to move the full range between the two ends). If it does, reconnect that wire and disconnect the other end of it. If the pot vo ltage still can change, the problem is on the board you just disconnected f rom, and we have to look deeper. Otherwise it's in the wire
Reply to
Jesse Bear

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