Marshall 6100 Blue Tolex - Intermittent Buzz

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by VanPaul, Feb 23, 2009.

  1. VanPaul

    VanPaul Member

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    Marshall 6100 Blue Tolex - Intermittent Buzz
    I have a Blue 6100 that has developed an intermittent loud 60 Hz buzz. I've had it in the shop now for many months and the tech can not figure out what is wrong.
    We are sure that the problem is in the power section. The symptoms are this.... when you turn the standby switch on or off there may be a momentary loud buzz. Also with the amp not in standby it will be just fine for many hours and then all of a sudden this buzz will appear. At this point, it may just go away as quicky as it started or I may have to put the amp in stand by or powering it down to fix the problem. Even that does not always work. It doesn't seem to be heat related because it will buzz weather hot or cold. Anyone with a 6100 heard of this problem before? I'm getting desperate here.
     
  2. Rosewood

    Rosewood Member

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    I would start checking all solder joints just to eliminate them. Can you cause the buzz by taping on the amp?
     
  3. SatelliteAmps

    SatelliteAmps Member

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    +1. I would shotgun the board and redo every solder joint, everywhere.
     
  4. RussB

    RussB low rent hobbyist Silver Supporting Member

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    I think the blue tolex has something to do with it :)



    Intermittent issues are troublesome to locate. I like Adam's approach in this case.
     
  5. SatelliteAmps

    SatelliteAmps Member

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    It's sometimes a lot faster and easier to just hit the entire board. That way you know you won't be dealing with cold solder joints. It's faster for me to just go through and hit all the spots than it is to get out the magnifier and the light setup to examine each one.
     

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