Final Assembly

Almost there! Let's finish up.


Take your time here. If the 3D-printed parts aren't fitting well together, don't force them -- you may accidentally break something. Instead, check for leftover support material that needs to be removed and gently carve it away with a utility knife.


  1. Affix PCB
    1. Slide 2 square nuts into the back PCB posts on the enclosure bottom half. Two square nuts in their posts
    2. Place the finished PCB into the enclosure bottom half, fitting the switch into its cavity. Placing the PCB into enclosure bottom
    3. Slide 9v battery into its space behind the speaker. It will be a tight fit. 9v battery
    4. Fit speaker into its container ring above battery. Try to hide any excess wire from the speaker under the PCB. Pressing the speaker into its container
    5. Secure PCB into place with 2 1/4" screws. Don't overtighten! Securing the PCB with screws
    6. Fit volume wheel onto RV21, matching its cavity to the trim pot's shape. As long as it's able to turn the underlying pot, it's okay if it's a little loose — it'll get held in place by the enclosure top. Adding a volume wheel to the trim pot
  2. Add keys
    1. Place mounting rail onto PCB, aligning its holes to the screw holes below. Adding the mounting rail
    2. Place keys onto mounting rail. Placing the keys onto mounting rail
  3. Finish enclosure
    1. Insert 4 square nuts into the nut locks on the enclosure top. A small dab of glue here on each is optional but will help hold the nut in place the next time you disassemble. Inserting square nuts
    2. Remove protective film from plexiglass window pane and fit it into the enclosure top. Adding the plexiglass window pane
      • It will fit but may be tight. If you're worried about breaking the enclosure top, you can use a utility knife to carefully trim down the two holder tabs to give the plexiglass window pane more room.
      • Alternatively, if it's too loose, let a line of glue dry in the long cavity under the nuts. Repeat until the fit is snug.
    3. We're about to lock it up, so now's a good time to make sure your POLY555 is fully tuned and has a good battery. Oh, clean any smudges off the inside window now too.
    4. Gently align the two enclosure halves, fitting the back hitches on the bottom into their matching cavities on the top. The enclosure bottom's hitches fitting into their cavities on the enclosure top
    5. Srew 4 1" screws into the four mounting rail holes on the bottom of the enclosure. Don't overtighten! Screwing the two enclosure halves together from the bottom

All Done!#

A fully assembled POLY555

You’re done!!

Take a selfie with your brand new and very incredible POLY555 synthesizer. Feel good! You're the best!!


When you can, please let me know how it went for you:

  • What did you like? Did you have fun?!
  • Not including printing time, about how long did it take?
  • Were there any parts missing or damaged?
  • Any problems encountered with the instructions?
  • Is there anything you'd change about the POLY555 itself?

I act and rely on customers' feedback to make future kits even better. Thank you so much!