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Fender Deluxe 85(red knob) Low overdriven output

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  • Fender Deluxe 85(red knob) Low overdriven output

    I have a Fender Deluxe 85 that has very low output and very distorted at any settings.
    I changed the output transistors, filter caps(main ones-they seemed to be cooked a bit) and c49 and c50 (these are next to R115 & R116 power resistors and two diodes)
    This area was cooked a bit on the other side of the board. All to no avail.

    I also cleaned all pots and jacks.

    I would like to work with a schematic and probe it from input to output with a speaker to find out where I am loosing the signal. Anyone have a schematic for this beast?
    Or any info that may help me to repair this amp?

    Thanks!
    Arn C.

  • #2
    Dumb Mistake!

    I tore out the board and started checking solder joints for the 2nd time and found that
    when I installed the output transistors, I forgot to solder them to the board!
    I guess I better check them again and maybe replace them again.

    Man, can't believe the oversight. I will let you all know if this fixes the problem at hand.

    Peace!
    Arn C.

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    • #3
      Okay, I got it working fine now. I replaced the transistors and soldered them in this time.
      I do have one more minor(I hope) problem with it tho. The reverb, with nothing plugged in
      I get hum. With reverb turned all the way down okay, but as I increase the reverb it gets worse
      and worse. It is just a steady hum...

      Any ideas what would cause this?

      Thanks!
      Arn C.

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      • #4
        a bad connection from the reverb output to the reverb return gain stage will cause hum that increases as you turn up the reverb control. kinda like when you unplug your guitar from the cable and leave the cable attached to the input, and as you turn up the volume you get a loud noise/hum due to the incomplete circuit.

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        • #5
          Bad Connections!

          Hey Billy, you were right! I just cleaned the rca jacks and plugs with contact cleaner, ran them in and out a few times and it sounds great now, quiet as a mouse!

          Thanks!
          Arn C.

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