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Xmt304 cooling fan not working. Please help me diagnose.

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  • Xmt304 cooling fan not working. Please help me diagnose.

    Xmt 304
    serial # MD09...(2013 model)

    Just bought this machine yesterday from a private seller.
    Fan does not turn on.
    At first start up I let it idling 10 minutes then mig welding apx. 10 minutes and I quit to diagnose ...(I'm a Little gun shy after older xmt350 violently blew up a capacitor the other day.)
    I then saw a post about leaving it in any electrode hot position to make the fan operate after a few minutes without welding.... well I let it idle for 15 minutes electrode hot and the fan never turned on.
    (Fyi. In Michigan but it is not cold here yet)

    I removed the welder hood and tightened down everything I could. Removed the fan grill and blew out the fan and visually inspected everything before turning on the power initially.
    Everything looked good.

    Does anyone have the service manual for this machine?
    Or perhaps a quick way to diagnose. (Disconnect and give the fan 24 volts to see if it turns on?)
    Or specs to ohm it out?
    Or whatever you experts on here would recommend?

    I've searched around and didn't find a solution. I saw lots of owners complaining it came on too often (wish that was the case here.) But not.

    Starting to think maybe I just got some bad juju around here.

    Thank you all in advance for helping out.

  • #2
    False alarm. Sorry guys. How do I delete a post?

    Just after I made the original post, the fan turned on with the welder just idling after about 15 minutes "electrode hot".

    I would still very much appreciate a service manual for this machine if anyone has a copy.

    Thank you!


    • #3
      Originally posted by MI Welder View Post
      ...mig welding apx. 10 minutes and I quit to diagnose...
      At what amperage and duty cycle were you welding during these 10 minutes?

      ... it is not cold here yet...
      Give us a number. No one knows what "not cold" is to you.

      I understand being gunshy, but at the moment, I don't see anything to make me suspect it won't come on when it's programmed to.


      • #4
        Temp in and outside is 65-70 degrees F.

        I was making pretty hot pulsed mig passes across apx. 3/8" thick plate of scrap. Not sure on exact settings. I started around 565 IPM and had it turned down to 500 IPM after the 10 minutes. And not solid solid welding for 10 minutes but quite a lot of arc time over 10 minutes. I don't know the amps or volts because with this 60M feeder you pretty much set everything with the IPM. Trim was at 60. Arc 0.

        Comparing it to my dynasty 200. The 200 dynasty fan turns on much sooner.

        I'm hoping it was nothing but me being jumpy. Not suppised to be welding today... I'm supposed to be painting, but couldn't let that new to me welder sit there untested.
        It's kinda like Christmas here anytime I get a new machine.
        I'm actually just happy it turned on and welded. (I hate the uncertainty of buying a welder that can't be tested prior to purchase)...but the price was right. And machine was not hot. I called miller to check the serial # before purchasing and everything checked out.


        • #5
          Originally posted by MI Welder View Post
          I would still very much appreciate a service manual for this machine if anyone has a copy.

          Thank you!
          If a service tech gets caught sharing a service manual they'll get in quite a bit of trouble...probably get cut off by Miller entirely.


          • #6
            Some versions of the XMT 304 manual are available online. Even Red-d-Arc has them on their website for the Extreme 300 and Extreme 360, which both should look familiar to you.


            • #7
              I'll check out the red d arc manual route.

              I am thinking the machine is fine. When the fan did come on yesterday it came on and sounded nice and powerful. It must have been close to turning on while I was welding until I chickened out. I have some more projects coming up and I'll give it a good chance to warm up next time.

              Thinking more.. it has been low 40s at night. Even though the air is 65 everything metal in my shop is much cooler... including the welder.

              I'll report back after I give it a good go in the next week or so..

              Thanks again for all the advice!


              • #8
                Between my miller machines that have the auto on/off fans, I find a great variance in cut on and off times. For example, it seems to take a lot to get the fan to kick in on my MM250, but my Regency 250 kicks on quite easily and it also turns off sooner. My syncrowave kicks on and seems like it runs forever before turning off. My Maxstar cycles on quick and off quick. My Airco 3a is always on and sounds like a black hole vortex.