Tig welding tips, questions, equipment, applications, instructions, techniques, tig welding machines, troubleshooting tig welding process
tractorkid17
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    Sun Apr 21, 2013 12:12 pm

Having trouble with my shop master when tig welding, every thing seems to work just fine. except I have no amperage control with the foot pedal, all I get is HF start with the pedal when I have the amp control set on remote. works fine if I set the amp control to the panel just have no way to taper off when I am done. Checked the foot pedal out, seems to work fine, I talked to a repair shop which talked me through that process. Unhooked the HF box and hooked the foot pedal right to the power source and just did scratch start, still no amp control with the pedal have to use the panel. Any body every have any problems which were close, or have any thing else to check which would narrow things down? Thanks
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    Tue Jun 26, 2012 8:05 pm

I've looked at this problem. Check your foot pedal first with a multi-meter.
The schematics are here. http://www.millerwelds.com/om/o322a_mil.pdf

As you can see from the drawings,
the panel/remote switch diverts the pot wiper (pin E on the pedal connector)
(110 on the circuit card) from the panel to the pedal (19).
The pedal is using a separate source and ground.
(source is pin C on the pedal connector, 105 on the circuit card)
(ground is pin D on the pedal connector, 42 on the circuit card)

If your foot pedal checks out,
(i.e. variable resistance between E-C or E-D when you move the pedal),
then check to see that the box side has a voltage reading between C-D.
Also, open the box and check the continuity of the panel/remote switch.

Beyond that, I don't have the drawings for the circuit card and would have to see it to troubleshoot it.
I typically use a Huntron Tracker to troubleshoot my circuit boards.
http://www.ko4bb.com/Manuals/09)_Misc_T ... erator.pdf
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Foot pedal.JPG
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tractorkid17
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    Sun Apr 21, 2013 12:12 pm

Thanks for the help. I checked the pedal out with a meeter tonight, I have variable resistance on the two pins however I don't have any voltage on C when I check between C and D. The book says that C should have 10V DC but I don't have anything there.
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    Tue Jun 26, 2012 8:05 pm

Your going to have to follow C back to the circuit board (RC54 pin 9).
(Circuit board RC54 pin 5 should also have 10vdc. It goes to the panel amp adj pot R1.)
If the panel pot R1 has voltage, follow the circuit board traces to RC54 pin 9.
(It should be using the same voltage rail.)

Also, its possible that the filter cap (C18) could be shorting out your 10volts to ground.
While you have the box open, check the panel/remote switch for continuity.
Remove, inspect and re-seat all related connectors. (Sometimes just a bad connection.)
tractorkid17 wrote:Thanks for the help. I checked the pedal out with a meeter tonight, I have variable resistance on the two pins however I don't have any voltage on C when I check between C and D. The book says that C should have 10V DC but I don't have anything there.
tractorkid17
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    Sun Apr 21, 2013 12:12 pm

This evening I followed C back to the panel, with minimal voltage at the panel, the meter reads about a tenth of a volt on both pin 9 and pin 5. The panel switch checks out.
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Can you explain to me, how the panel amp control (pin 5) is functioning without the proper voltage?
Where are you connecting your ground? Also, can you attach a photo of the circuit board?
tractorkid17 wrote:This evening I followed C back to the panel, with minimal voltage at the panel, the meter reads about a tenth of a volt on both pin 9 and pin 5. The panel switch checks out.
tractorkid17
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    Sun Apr 21, 2013 12:12 pm

I need to recheck things tonight, I was getting some off readings with my meter, found a broke wire on my meter, I will try to get some pictures and do some more testing tonight. You'll have to be patient with me through this, wiring isn't my specialty. I do really appreciate the help though, the closest repair place is about 50 miles away that's why I am trying to figure it out myself.
tractorkid17
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    Sun Apr 21, 2013 12:12 pm

Fixed the wire on my meter tonight and started checking things again, the only thing I really did was test some more with the panel switch for the remote, checking for voltage, was moving the connections around and things started working, ran some beads and my amp control on the pedal works real nice, I am assuming a bad connection, I will be cleaning them up and putting it all back together tomorrow after work. I think i have some dielectric grease around here some where, Would there be a benefit to using that too after cleaning things up? Thanks for all the help, hopefully it doesn't turn into one of those on again off again things.
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    Tue Jun 26, 2012 8:05 pm

Glad to hear that you got it working. It's usually something simple.
Dielectric grease can help prevent further corrosion but I prefer to re-tin my connections with solder first. (Use lots of flux.)
The following video is dry and boring, but it has some crucial information in it. https://www.youtube.com/watch?v=vIT4ra6Mo0s
tractorkid17 wrote:Fixed the wire on my meter tonight and started checking things again, the only thing I really did was test some more with the panel switch for the remote, checking for voltage, was moving the connections around and things started working, ran some beads and my amp control on the pedal works real nice, I am assuming a bad connection, I will be cleaning them up and putting it all back together tomorrow after work. I think i have some dielectric grease around here some where, Would there be a benefit to using that too after cleaning things up? Thanks for all the help, hopefully it doesn't turn into one of those on again off again things.
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    Tue Jun 26, 2012 8:05 pm

BTW - Why is your name tractorkid?

A few months ago, I bought a CASE 2470 for my little acreage.
200hp turbo diesel, 175hp at the PTO, 8WD (duals front and rear).
Best $5,000 that I ever spent. It's well maintained and purrs...
https://www.youtube.com/watch?v=A-Yh4dv8NJ0
The service manual and a diecast toy model were unavoidable.
I plan on running my new toy with single tires and lots of attachments.
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tractorkid17
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Name's Bob, live in WI, one little one now, and the wife and I happen to have a little acreage as well. Bought a little hobby farm last year, it's old but sure feels like home. I mess around with old tractors on the place and such, fixing things, making hay, all that good stuff. Happen to have a farmall B apart right now, got the crank back last week now just need to order a kit and put her back together, been needing that for a long time. Have a woods mower to put on it when it is back together, sure will be nice mowing the yard with that instead of the dinky little rider. After that have to get the old milk house ready for some chickens, build a scalder and a plucker, then after that put up some fence. And the list just continues, well for a long time, and working during the week adds plenty more to do. Lots of irons in the fire, but keeps me out of trouble. Thanks again

Bob
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    Tue Jun 26, 2012 8:05 pm

Hey, your welcome. Glad I could be of some help.

I bought my small acreage last year, mid December.
I want to build wind powered greenhouse domes.
Its very windy in southern Alberta which robs the soil of moisture.
I'm going to install vertical axis wind turbines over the entire dome area.
I got the idea when watching roof ventilators.
http://www.originalshedco.com/accessori ... LYBIRD.jpg

The turbine will run on a track at ground level.
A driveshaft will connect thru the roof, to a generator at ground level.
(This makes it easy to service the roller wheels and generator.)
Any excess wind energy will be used to heat water electrically.

Turbine speed will be controlled by adjusting the electrical load.
If the wind gets too strong, more water heaters are employed automatically.
Water is an excellent medium for storing energy.
It can be used in part for GeoThermal heat storage for the winter months.
The advantage of this type of wind generator is the safety.
You could literally walk into it, and it would just push you away.

http://www.genesisgeodesica.com.ar/imag ... -domes.jpg
tractorkid17 wrote:Name's Bob, live in WI, one little one now, and the wife and I happen to have a little acreage as well. Bought a little hobby farm last year, it's old but sure feels like home. I mess around with old tractors on the place and such, fixing things, making hay, all that good stuff. Happen to have a farmall B apart right now, got the crank back last week now just need to order a kit and put her back together, been needing that for a long time. Have a woods mower to put on it when it is back together, sure will be nice mowing the yard with that instead of the dinky little rider. After that have to get the old milk house ready for some chickens, build a scalder and a plucker, then after that put up some fence. And the list just continues, well for a long time, and working during the week adds plenty more to do. Lots of irons in the fire, but keeps me out of trouble. Thanks again

Bob
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