No announcement yet.

Older Hobart 120 with bad diodes

  • Filter
  • Time
  • Show
Clear All
new posts

  • Older Hobart 120 with bad diodes

    Hi All- I have an older 120 with diodes that have failed. I also notice that one of the two tiny ceramic capacitors attached to the diodes is split. I have ordered the diodes and they should be in on Friday but I was wondering about the capacitor. It doesn't appear to have ever been soldered well onto the diode. It simply came off when I started to remove the diode from the aluminum plate. I don't see any mention of these capacitors in any of the threads and wondered if they are problematic. I also don't see any place to get them and was wondering if any 100V capacitor would work or if the was a particular capacitance I need to find?
    Thanks for your help.

  • #2
    I wouldnt worry about them, they are supposed to protect your rectifier never seen one yet that does


    • #3
      diode repair

      The capacitor is important to keep the diode alive . It sounds like yours was bady soldered or connected to the diode which is why it failed.The value is not critical somthing around .1 mfd 100v will do. If you really want the Hobart part # is 368705-20 you could call them to see if they have any replacements or could give you an exact value.


      • #4

        I just talked to the Miller/hobart folks and they don't show that part number exactly, one that is close. They are checking to see what the correct # might be. I sort of suspected that those capacitors might have played a role in the diodes failure. They usually aren't inserted for looks.


        • #5
          Handler 120 diode caps

          The caps are rated at .01mfd/100Vdc. The old part# was 368705-020, which is no longer available. A cap close to this value will work and are needed to help protect the diode from dying prematurely.



          • #6
            Thanks Keith

            Yeh the dealer I talked to has been getting replacements from an electronics store locally. I'll run over tomorrow and pick up a couple of caps. Thank you all for helping to solve my welder dilemma!