Anyone had issues with 2555X control pots?

Discussion in 'The Workbench' started by Noise Under The Floor, Jul 13, 2020.

  1. Noise Under The Floor

    Noise Under The Floor New Member

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    I have a 2555X Jubilee reissue that I bought brand new when they were first released. Recently two of the control knobs, the mid and bass seized up and became very difficult to turn. It got to a point where I had to use a lot of effort, and the mid knob just snapped off at the shaft.

    Anyone else had anything like this happen? I should note, this amp has been babied. Rarely left the house or my music room. I’ve owned quite a few amps and never had anything like this happen.
     
  2. Gunner64

    Gunner64 Well-Known Member Premium Member

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    Yep. I bought one new from sweetwater that had a stiff pot on delivery. I immediately sent it back and got another. The second one was perfect, and all pots turned like butter.

    My buddy bought one that had a stiff pot too..there has been numerous reports of this condition in the 2555x. Some have said the shafts became so tight they snapped, like yours.

    Imo a bad batch of pots went into these amps..really a shame because the amp itself is killer.
     
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  3. anitoli

    anitoli Well-Known Member

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    Yup, the mid pot on mine is very tight. The shop informed me of this when i bought it so there wasn't any surprise. I'll change it when it needs be.
     
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  4. Noise Under The Floor

    Noise Under The Floor New Member

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    Dang! Well, good to know I’m not alone. It’s weird how the two on my amp became stiff over time. They were fine for the first 5 years I had it then all of a sudden started tightening up. Going to have to get it into the shop ASAP. I might just have them change all of them to avoid future problems.
     
  5. dragonvalve

    dragonvalve Well-Known Member

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    I have that on my SL. I'm thinking it's the lube (grease) in the pot used to make the sweep smooth and gradual. Must be dried up.

    Perhaps using a proper cleaner and then replacing the lube would work if these pots have open cans (I don't know, never opened my SL) for a cleaner straw to fit.

    Then use the syringe that comes with this excellent contact grease.
    [​IMG]

    CONUS dealer:

    https://www.newark.com/electrolube/cg53a35sl/contact-treatment-grease-35ml/dp/57AC5786

    Even just squirting some cleaner in the pots may get them to move so they don't snap until you can get contact grease.
     
    Last edited: Jul 14, 2020
  6. wmachine

    wmachine Well-Known Member

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    Seems the problems pots were all stiff to begin with. This is the first I've heard of them (unusually) stiffening up over time. Still may be the same defective pots, though. Just takes longer to manifest themselves and cause problems. So it looks like some of us that escaped the problem initially may face it later.
     
  7. Gunner64

    Gunner64 Well-Known Member Premium Member

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    I'd speculate the failing pots were a bit stiffer than the rest when new, and got worse from there over time. If they were crimped too tight to begin with there's only so much area for lube to do it's job.

    Imo Another factory flaw that should be repaired free of charge, as new units were shipped with this condition.
     
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  8. dju

    dju Member

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    yes, I had the same problem on my 2555x. the mid seized and the treble was a stiffer than most of the rest of them. i tried deoxit and it helped some but the mid just needs to be replaced. when trying to remove the mid knob i broke the pot shaft. that knob just did not want to come off. finding replacement pots turned out to be more difficult than i would had thought it would be. i was able to find the mid pot but unfortunately they didn't have the correct treble pot value. the mid pot should be here this weekend. i had a heck of a time getting the busted pot shaft out of the knob. might need to get a new knob as well. and the correct black knobs with silver top for d-shaft pots, well those are as rare as hens teeth as well. if anybody knows where to get the CORRECT knobs let me know. with so many people having problems with pots i wonder if Marshall would do a extended service advisory for this problem. probably not.
    good luck,
    dj
     
  9. wmachine

    wmachine Well-Known Member

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    It would be "the right thing to do" even if technically not covered by warranty. At least sending replacement pots and knobs would not be that involved for Marshall, and is reasonable. I think I recall someone trying to get help from Marshall and they didn't get anywhere?
     
  10. Gunner64

    Gunner64 Well-Known Member Premium Member

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    But Just like the JCM2000 dsl pcb issue, they'll sell you parts to fix their mistake..:)
     
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  11. Noise Under The Floor

    Noise Under The Floor New Member

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    Exactly how it happened for me. Shaft is still stuck in the mid knob. Taking it in to an authorized repair shop tomorrow. I’ve owned a lot of Marshalls in my time, going back to an original Jubilee in the early 90s. This is complete BS.
     
  12. dju

    dju Member

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    I have the replacement mid pot (100k) purchased and I'm waiting for delivery. I would really like to replace the sticky (but not frozen) treble pot while I have the amp apart. but so far I haven't been able to locate the B220K d shaft pot for the treble. I am also having problems finding a replacement jubilee silver d shaft knob to replace the one that got damaged when I tried to remove the busted shaft from the knob. I am considering just getting splined pots and replacing all of them as I can more easily find replica silver spline knobs and pots.
    Tomorrow I plan to call my local guitar shop to see if they can point me towards a local marshall service center that I can maybe buy the parts from.

    does anybody have a source for authentic 2555x knobs and a B220k d shaft pot?

    thanks,
    dj
     
  13. dju

    dju Member

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    found some of the B220k pots on ebay from the UK. and some knobs from an Marshall MG amp also on ebay. they look the same and they are for D shaft pots so in maybe a month I should be good. depends on shipping time from UK for 220k pots.
    dj
     
  14. Noise Under The Floor

    Noise Under The Floor New Member

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    Do you happen to know the part numbers for the pots? I’m having trouble finding them and so is my repair tech.
     
  15. Adrian Hallas (Toneworks)

    Adrian Hallas (Toneworks) New Member

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    They are made by Taiwan Alpha and look like model number: RV16AF20-A1-15F-B220K
    They're difficult to source in small quantities in the UK.

    Hope that helps.

    Cheers,

    Adrian
     
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  16. Noise Under The Floor

    Noise Under The Floor New Member

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    Thank you! No, not easy to find.
     

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