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Fender Champ 600 screeches when turned on

Discussion in 'Amp Tech Center' started by skeletool, Mar 2, 2017.

  1. skeletool

    skeletool NEW MEMBER!

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    A while ago I made the mistake of cranking my little champ 600 while playing through a EH Big Muff. After playing for a minute, I heard a pop and the amp just started playing screeching feedback.

    I noticed that the powertube was blown so I replaced that. I turned it on and it is still making the noise, even when volume is at zero! I also had some spare 12ax7's and replaces the pretube and that didn't change anything at all.
     
  2. skeletool

    skeletool NEW MEMBER!

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    I would like to add that i tried the amp through another speaker also and made the same noise so it is definitly an issue with the amp
     
  3. Bendyha

    Bendyha Friend of Leo's Silver Supporter

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    check that the screen grid resistor isn't shot....R26...the one under the word instruments. Search all the area and surrounding parts for signs of burning. I've had a 600 to fix that had the PCB track damaged through burnt out resistors....or was it by the tube socket solder tabs...can't remember.

    upload_2017-3-2_20-39-54.png
     
    Last edited: Mar 2, 2017
  4. Bendyha

    Bendyha Friend of Leo's Silver Supporter

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    While your at it check R10 as well..the correct values are seen here;
    upload_2017-3-2_20-53-52.png
     
  5. otterhound

    otterhound Poster Extraordinaire

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    My apology for the hijack , but looking at the second schematic makes me chuckle just a bit . I replaced the 6V6 in mine with a good 6V6 that I had cannibalized from a car radio . The funny part came later when I checked out the 6V6 that it came with . It really isn't a 6V6 . It is a 6L6 .
     
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