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  #161  
Old 05-11-2007, 09:23 PM
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GWIZ GWIZ is offline
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Why this machine ended up in the scrap pile.

After examining the evidence, I came to the conclusion that someone connected AC power into the remote current control receptacle (3 prong foot pedal plug). more then likely from an AC wall outlet, that shorted out the rectifier bridge (SR2) and more then likely damaged the current control rheostat.

A rectifier bridge has 4 individual diodes inside. Your test concluded that all 4 diodes were shorted.
When these bridges go bad one or two diodes go bad , never 4 diodes at once.
The only way I can see 4 diodes going bad at the same time is reverse feeding power into the bridge.
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  #162  
Old 05-14-2007, 03:57 AM
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GWIZ GWIZ is offline
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VW,
That's a great picture in your post #160.
The way the light beams out in different directions.
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Originally Posted by VW
just glad to get it to this point. Any ideas on a foot pedal resistor GWIZ? Thanks, Phil
The foot pedal.
I keep going back and forth in my thinking, and I keep coming back with the same conclusion. I would have to wire the Transistor and make some of the linkage to connect to a sliding control.

Without me having direct access to your welder, I would say that the success in making a working electronic control is 75%.

I Would be surprised if miller has someone still making the resistors.
As for some other type of resistor, never seen one that short in size. most are long just like that 20 ohm resistor you used in testing the rheostat.
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  #163  
Old 05-14-2007, 05:37 AM
VW cat VW cat is offline
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GWIZ, Whattman,
I don't think the dealer has found that resistor, or he would have called. So I was planning to look for a used foot pedal, if I can find the right one. I don't have Craig's List in this area. I keep thinking of the foot controls used on electric sewing machines, or a rack and pinion turning a circular rheostat. It's not a high priority for me right now; I'm very happy to see this project finished. Mounting the welding cables on the unit is next, as well as learning the basics of tig welding. The Liquid Carbonic unit is officially retired. I've learned alot and thank you again for all your help. Philip

P.S. I found 2 portable Lincoln welders in the scrap
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  #164  
Old 05-14-2007, 09:48 AM
Whattman Whattman is offline
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Just some info, VW. Probably with the currency exchange and this being on ebay it wouldn't help much. There is a picture of the unit.

"brweldingsupplies" has the pedal new for $305 US. Item 280103120288.

http://cgi.ebay.com/MILLER-REMOTE-CO...QQcmdZViewItem
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  #165  
Old 05-15-2007, 06:22 AM
VW cat VW cat is offline
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Nice to have a good clear picture of it Whattman. I have saved the picture and the information. Thank you very much. Phil
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  #166  
Old 11-08-2007, 05:48 PM
jmcwilli76 jmcwilli76 is offline
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I know this is an old post but you could look at a mechanical speed controller for a radio controlled car. The old ones used a large variable resistor. If you have a local RC hobbie store they might have one.
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  #167  
Old 11-09-2007, 07:15 PM
VW cat VW cat is offline
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I'm still looking for a used foot control or equivalent. Not sure about your idea. Mainly using the machine for stick welding lately, it's a pleasure to use and I gave it a good workout yesterday, welding a piece of cutting edge material to repair a backhoe bucket.

I've never forgotten the help I got for this welder project. Phil
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