Wednesday, August 18, 2021

Replacing a Digitech Whammy Knob and Rotary Selector

DOH!!!  Why a plastic shaft!?!?!

        So..... you knocked the knob off your Digitech Whammy?  When I did, I thought it would be a cheap fix with a some sort of simple potentiometer.  While the fix itself was easy, it was not super cheap.  All and all it set me back at least $20 just for a little knob I probably kicked off during a show.  You'll most likely need two things special ordered along with all your average soldering and pedal tools.

These are what you'll need and what will set you back the most. (Almost like Digitech wants you to spend more on repairs.)   

  • Rotary encoder with 24 pulses with a 15mm shaft. (ebay seems to be the only place to find these.  Type those exact words into ebay.  Probably $15 for a set of two.  Might as well pick up an extra considering the shaft is plastic and it'll break again.  
  • #4
    7/64" Allen wrench (Not a common size in most sets.  As hard as I tried to buy locally, Amazon was the only place that had one)

You'll also need your basic soldering iron, solder, solder braid (to remove the old solder), a screwdriver, wrench and possibly wire cutters or pliers.

Take the casing apart by removing the top allen screws then remove the two screws with the screwdriver next to the "midi in".  With a little gentle sliding up and away from the "midi in" jack the top should come off with the board.   By now you should see picture #2.  Next we'll unscrew the washer holding the broken pot.  The top board will come loose.  Picture #3 at the bottom shows the 5 solder points we want to de-solder.  Honestly this is the hardest part.  Don't heat the points too long.  Use solder braid to lift the old solder.  You might need wire cutters or pliers if the old rotary encoder is stubborn to come out.  After the old broken rotary encoder is out, pop in the new one and solder it in.  (If the new rotary encoder has small metal tabs on the top sides like mine did in up top in picture#4, you may have to snip those off to fit it flush to the enclosure.) Then put everything back together.  Hopefully you didn't loose the original knob like I did and yours looks totally original.  My orange knob was all I had on hand at the time.  I'll have to get something better in the future.  Hopefully this helps you bypass Digitech customer support and shipping.  Good luck out there.  
What a looker...