Looking for insight on trouble shooting a Marshall 6101

Discussion in 'Glowing Bottle Tube Amp Forum' started by Mike_LA, Mar 6, 2019.

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  1. Mike_LA

    Mike_LA Tele-Afflicted

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    Looking for insight on trouble shooting a Marshall 6101

    Well I've had this baby for years and somewhere in it's life I'm sure it was dropped a few times.
    It has had an intermittent problem of loosing the treble pot on channel 1.
    Looooog story/short, I finally fixed it by re-soldering the spade connectors.

    However; now I have what seems to be a static issue.
    If I tap anywhere on the amp I get a scratchy static sound. It's everywhere, so where do I start?
    Please see see vid for more info.
    Your help is greatly appreciated.


     
  2. MuddyWolf

    MuddyWolf Tele-Meister

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    Sometimes pots are grounded by contact against the chasis. Maybe you disrupted that.
     
  3. corliss1

    corliss1 Friend of Leo's

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    That's a good guess with the grounding. You can also do more tactical chopsticking my trying to gently move individual wires and connections and see what's up, but if this just occurred after a recent change to the pot, it's likely related to that work.
     
  4. Mike_LA

    Mike_LA Tele-Afflicted

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    I didn't change any pots, I just re-soldered some bad solder joints.
    I took it apart again and checked all of the fiber washers and they are all present
     
    Last edited: Mar 6, 2019
  5. bftfender

    bftfender Friend of Leo's

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    go to Marshall Forum look up Anitoli,,he works on em & is a 6100 fanatic..love my 6100
     
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  6. Mike_LA

    Mike_LA Tele-Afflicted

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    Yah, I know Pete pretty well.
    I only bother him as a last resort on 6100 specific questions.
    If we weren't on opposing coasts I would have shipped it to him long ago . . .
    This is not specific to the marshall but to tube amps in general.
    I'm leaning toward a grounding issue as well.
     
  7. Mike_LA

    Mike_LA Tele-Afflicted

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    Well, I'm full blown gonzo confused.
    I changed the PI tube just cuz.
    When I turned on the amp I got an increasingly loud buzz.
    Put the Old tube back, turned it on.
    Quiet as a mouse.....
    ??!?!?!??!?!?!?
    The tube socket in question looks to be a little heat distressed from all of the years, might have to change that socket . . . .
     
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  8. peteb

    peteb Friend of Leo's

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    Good to hear you found it




    I think crackly scratchy static sounds are the sound of a bad/intermittent connection.

    The idea that it was caused by a faulty ground really meant the ground connection was faulty.

    And when I say intermittent I don’t mean comes and goes, but it meant the connection not making complete connection.

    You found the area, the tube socket. There must be a bad connection in that area. I’ve found some pins to be very loose. Maybe the pins need tightening.





    Those are just my thoughts in trying to relate sounds to symptoms.
     
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