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I need help with my Dialarc HF 300

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  • I need help with my Dialarc HF 300

    So I figured this would be the best place to ask for help on my early 90's Miller Dialarc HF-300. I bought this machine used about 4 years ago and have had great success with it. The previous owner had built a rolling cart with a 30 gallon stainless steel tank for the watercooled torch. Its a great welder and I've been very happy with it for the time I've used it which is about 5 times a month. I've gone through 5 bottles of argon since I started using it 4 years ago. All that being said, today while welding some .250" thick aluminum plate I experienced what can only be described as a surging or cutting out of the arc. I could hear the HF buzzing along as I have the HF on Continuous for welding in AC, but the arc was intermittent and pulsing on and off. This has never happened before and I stopped to make sure I had a good positive ground but everything was fine.

    Has anyone else ever experienced this? Could this be a failing transformer inside? I have the amperage settings on the middle position with the dial at about 90%. So its not running at maximum or anything. I'm just a bit miffed as I've been very good to take care of this machine.

    On an unrelated note I've noticed what sounds like a failing bearing on the cooling fan but the fan continues to work fine and has never stopped, just whines a bit. So at some point the bearing will need replacing.

    Thanks for your help. Talk soon Travis

  • #2
    I think its torch time.... replacement that is.

    Now there is 2 types of fan motors, if its the bearing type, and its squealing now, best replace the bearings NOW. It's rather expensive. If its the brass bushing type, best re oil the cups NOW for the same reason.
    Last edited by cruizer; 09-12-2012, 07:06 PM.


    • #3
      So what replace the torch handle? I'll pull the fan cover off tonight and see what kind of fan it is. Thanks again.