Remove the part from the circuit board, take pictures and create a dimensioned drawing. If the part is damaged, use an undamaged one for the pictures. Pay particular attention to the size and location of the terminals, any mounting tabs or holes, the size of the slider and the length of the sliders' travel. Create an email, preferably one page, that you can fire off to distributors and manufactures.
Look at any small marks in the plastic. Some may be a logo or trademark you wouldn't normally think is one. A "2" in a circle is a Sprague trademark. An "H" in a circle is a Hammond trademark. If you find anything, try to track down who it belongs to. "KOD" might be a trademark, search the internet to see if you can identify that. Look for all companies that manufacture slide pots, check drawings online to see if someone makes a part that will fit.
Try to track down anyone who serviced Sunn or Biamp mixers and might have parts in stock. Fender might be a good place to start and Biamp is still in business although they don't make MI mixers any longer.
