myersbw

JCM900shear

JCM900shear
myersbw, Mar 1, 2018
    • Gutch220
      Thanks. What do you mean by 'loosen'? Loosen what from what, the nut in the second pic? I really don't want to remove the pots from the PCB at this point because I would just install new pots at that point. How would I fix the problem you described above?
    • myersbw
      What you do is loosen the nut on the pot as it's attached to that riveted pcb-mounted steel plate. If you don't loosen it, you'll likely never see the shear. You don't have to remove it completely or desolder. If you loosen it and it is sheared...the pot will just fall loosely. If not, just tighten back up. You do have to remove the plate from the front chassis by taking out those sheet metal screws that attach it. If you don't check it...you can end up with an intermittent issue for years that will drive you insane (or, have never found the true source of issues...or eliminated them). Unless you're gigging a lot with your amp, you'll likely only have to do this once. it's not bad...no need to desolder anything unless you see that a pot is sheared.
    • Gutch220
      what exactly do you mean by sheared? and when you say 'fall away' do you mean the phenol disk falls away?
    • myersbw
      Ok...by sheered, that's referencing how something is cut. So, in this circumstance, the pot's leads are cutoff by a quick smack on the face of the pots...like a quick bump. Basically, smacked hard enough that the metal part of the pot smacks fast into the pot's lead board and it cuts (or sheers) it. Just like my photo shows.

      Now, the bad part (well, besides the cut or break), is the the pots spring back...everything goes back into place...the leads are now only held in place by the soldering to the board...and the pot is only held in place by the nut securing the shaft. So...loosen the nut or remove it and the pot (if broken) will just fall away.
    There are no comments to display.
  • Category:
    Marshall Amps
    Uploaded By:
    myersbw
    Date:
    Mar 1, 2018
    View Count:
    314
    Comment Count:
    4

    EXIF Data

    File Size:
    1.8 MB
    Mime Type:
    image/jpeg
    Width:
    3264px
    Height:
    2448px
    Aperture:
    f/2.4
    Make:
    Apple
    Model:
    iPhone 5
    Date / Time:
    2013:10:19 16:49:56
    Exposure Time:
    1/17 sec
    ISO Speed Rating:
    ISO 400
    Focal Length:
    4.12 mm
     

    Note: EXIF data is stored on valid file types when a photo is uploaded. The photo may have been manipulated since upload (rotated, flipped, cropped etc).