Miller A/C no high end

[ronbo]

I have a Miller Thunderbolt 225V A/C only. I've used it in the low range with no problem (30-150 amps). When I switch the lead for the high range (40-225 amps) I get nothing. Not even a small spark. I've downloaded the manual from the Miller web site and it has not been much help. I have not opened the box yet so there may be just a wire loose but common sense says that both high and low terminals would be hot when it is turned on. Sooooo how can one work and not the other?
Thanks
RON

[slamdvw]

I'd have to venture a guess that a connection is corroded... Looking at the schematic it's a simple machine. In the wiring, 'high' is before 'low' so yea... that kind of rules out the xfmr being bad.

Let us know.

[MJDamiani]

Please open the case. I'll bet that the problem will jump out at you. Bad or corroded connection in the high end circuit.

[MicroZone]

Give Miller a call. They deal with these problems a thousand times a week, day-in, day-out and will get you an answer quickly without having to fiddle with your machine.

Miller Electric Phone: 920-734-9821

[ronbo]

Thanks for all the replys. I will get out and pull the cover as soon as the temp gets back into double digits. My garage is not heated. I'll let you know how I make out. Looks like it may be a few days.
Thanks RON

[ronbo]

Well I finally got the cover off this morning and checked things out. A lot of dust and dirt in there but no corrosion. I blew it out with the air hose and checked everything I could for tightness. I polished the connector sockets on the front of the machine and the plugs on the cables with some emory cloth and blew everything off again. Turned it on and ZAP! struck an arc on the high and low circuit. I guess it's always best to check the simple things first.
RON

[MicroZone]

There you go, glad you got it working!