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Ashdown peacemaker 40 problems

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  • #1

    Ashdown peacemaker 40 problems

    I've had one of these amps for a few years (got it in a trade ) for cheap with a hum
    I have read post here with the same problem & I've diagnosed this amp with the problem being the hot glue melting & getting in a couple of tube sockets .so i managed to clean them up & installed tubes & I've had no sound
    so while trouble shooting no sound from the amp all tubes were glowing but this resistor R76 470R got really hot & started to smoke & died it's the resistor that connects from the center tap of the output transformer & the 2 47u filter caps .

    I'm curious what would cause this problem a bad tube maybe
    Attached Files
    Last edited by copperheadroads; 10-17-2016, 05:39 PM.
    "UP here in the Canada we shoot things we don't understand"
    Tags: None
  • #2
    Does that point called C2 feed the power tube screens? If so, likely a bad power tube is causing the resistor to burn. If not a bad power tube, then something else connected to C2 or downstream of it.
    Originally posted by Enzo
    I have a sign in my shop that says, "Never think up reasons not to check something."


    ​

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    • #3

      I see at the top of this schematic towards the right side Near V2a looks C2 or G2 ..hard to tell but if it being C2 it would feed the screens
      "UP here in the Canada we shoot things we don't understand"

      Comment

      • #4
        That is a 'G2'.

        Look on the power supply page.

        It is between CT & HT1.

        Comment

        • #5
          Originally posted by Jazz P Bass View Post
          That is a 'G2'.

          Look on the power supply page.

          It is between CT & HT1.
          In Schematic terms what is G2 ? Grid 2 ? makes sense
          "UP here in the Canada we shoot things we don't understand"

          Comment

          • #6
            In a beam tetrode (6L6-6V6)/ pentode (EL34) output tube, yes.

            Grid 2 is the Screen.

            Click image for larger version Name: 6L6 pinout.jpg Views: 1 Size: 37.3 KB ID: 844018

            Click image for larger version Name: EL34.jpg Views: 1 Size: 27.0 KB ID: 844019
            Last edited by Jazz P Bass; 10-30-2016, 03:57 PM.

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            • #7
              I'll disagree with Jazz here and say that marking on the schematic is C2, not G2. In any case, the point in the power supply labelled C2 is feeding the screens.
              Originally posted by Enzo
              I have a sign in my shop that says, "Never think up reasons not to check something."


              ​

              Comment

              • #8
                C2 is the power supply node for the G2s.
                Education is what you're left with after you have forgotten what you have learned.

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                • #9
                  Not to be pedantic, but I blew it up larger & the symbol is most certainly a "G".

                  You can see how the upper left corner squares off as opposed to the rounded "C".

                  http://music-electronics-forum.com/a...maker-40-b.pdf

                  Maybe it's my eyes.

                  At any rate, it is a confusing font that the engineer picked.

                  Comment

                  • #10
                    Appears you are correct. No problem as long as the point in the supply and the point shown up by the upper power tube are the same.
                    I had erroneously read the point in the supply as C2.
                    You can amend my statement in post #2 to read G2 rather than C2.
                    Originally posted by Enzo
                    I have a sign in my shop that says, "Never think up reasons not to check something."


                    ​

                    Comment

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