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Dialarc 250 HF start?

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  • Dialarc 250 HF start?

    I have a mid 1980's Dialarc 250 HF I was having a problem with tig high frequency start not working. I was practicing on 1/8" steel, ground clean no mill scale, good ground, dcen, arc won't start with hf. Water cooled torch with foot pedal. Cleaned and adjusted points .008" still no hf start. Then I read someplace someone said if you touch tungsten to work piece a time or 2 then try hf start and now it works every time. Is there something wrong or is that common that you need to touch the work piece with tungsten before starting?

  • #2
    Change the points. Cleaning might help but points are cheap. If that doesn't work your transformer or caps are weak or HF is jumping to a spot inside. Sometimes these old machines with corrosion find a better path.

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    • #3
      If you're confident everything on the machine is correct and the issue persists try increasing the post flow.
      In my limited experience the tungsten can get fouled up if it's not getting enough Argon coverage after the arc is extinguished.
      It''s far more noticable with larger diameter tungsten running higher amperage.
      Ditto on the points and I cant confirm on the .008" you may need to bring them to .004" in some cases.
      Goodluck champ

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      • #4
        Funny thing is it works perfect as long as I tap it and touch it to the metal before stepping on the pedal the hf starts from almost a 1/2 inch away.

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        • #5
          1997CST mentioned that there could be a loose connection (inside) the machine.
          It's kinda like lift arc with pedal delay lol

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          • #6
            Someone said when you touch it to the metal it senses dcen polarity then will work? I haven't tried it yet on AC. I can't find anything loose, points don't look to bad. It's a 35 year old machine that stick welds like a dream. If all it requires to tig with hf is to touch the metal once before starting arc I can live with it I guess.

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            • #7
              Is your tungsten green ?

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              • #8
                If the machine sat behind jesus christ in the fourth grade you can assume the torch went to the same high school.
                Perhaps invest in a fresh torch set?

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                • #9
                  Originally posted by Eriksat1 View Post
                  Someone said when you touch it to the metal it senses dcen polarity then will work? I haven't tried it yet on AC. I can't find anything loose, points don't look to bad. It's a 35 year old machine that stick welds like a dream. If all it requires to tig with hf is to touch the metal once before starting arc I can live with it I guess.
                  A while back I bought a Lincoln Square Wave TIG 175 from the original owner and it was like new....really minty. He bought it for a side job that never happened so he used about 200psi of a 125cu ft bottle practicing and then it sat in his garage. It looked like a floor demo model. It was spotty about starting the arc, so I checked the points and then hit them with compressed air...no change. If I touched the tungsten to the work and then lifted it and hit the pedal the arc started perfectly every single time. I wound up selling it to a guy who uses an older Syncrowave 250 at work and I noticed him touching the tungsten before starting the arc and I asked him about it. He said his machine at work didn't always start if he didn't ground the tungsten first. I don't know how common it is, but it sounds like it's not exactly rare to have this happen.

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                  • #10
                    I had a really good green import inverter that did the same thing, I passed it on to my brother and after you basically tell the machine where ground is, it works flawlessly the rest of the day.

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                    • #11
                      What color is your tungsten? Disable HF before trying monitoring the voltages in pictures or the risk damaging your meter.
                      Last edited by Popscott; 02-15-2020, 07:37 PM.

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                      • #12
                        I was using blue lanthonated tungsten on steel dcen

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