Skip to content
Back of the Box Builds

Back of the Box Builds

LEGO Alternate Builds!

  • SETS
    • Adventurers
    • Aquazone
    • Belville
    • Building Set with People
    • Castle
    • Duplo
    • Fabuland
    • Harry Potter
    • Holiday and Event
    • LEGOLAND
    • Model Team
    • Pirates
    • Space
    • Star Wars
    • Technic
    • Town
    • Universal Building Set
    • Western
    • More Sets
    • Misc
  • USEFUL LINKS
    • Submit Instructions!
    • New Instructions
    • New Official Sets
    • New Alternate Builds
    • Minifigs
    • Very Small Builds
    • Small Builds
    • Medium Builds
    • Large Builds
    • Extra Large Builds
    • How BOTBB was Built
  • THIS IS AN INDEPENDENT SITE NOT AUTHORIZED OR SPONSORED BY THE LEGO GROUP
Alternate Builds Instructions Added Medium Alt Build Medium Builds Spyrius Spyrius Alternate Builds 

6939 – Back B

February 5, 2023February 13, 2023 Master Builder 4132 Views

From: 6939: Saucer Centurion
Name: Spy-star Defender 1
Instructions: View PDF | Download .io File

Contributions

  1. Name, PDF and .io file submitted on February 5, 2023 by: Valdis
  • ← 6939 – Back A
  • 6939 – Back C →

You May Also Like

6349 – Back A

July 1, 2021July 1, 2021 Master Builder

7144: Slave I

October 28, 2021October 28, 2021 Master Builder

6055 – Back B

August 7, 2024October 1, 2024 Master Builder

918 – Back E

September 2, 2025September 3, 2025 Master Builder

6648 – Back D

May 18, 2022May 23, 2022 Master Builder

6337 – Back D

December 4, 2023December 4, 2023 Master Builder

EXPLORE MORE OFFICIAL SETS

6923: Particle Ionizer
ABCs M:Tron M:Tron Sets Medium Builds Official Sets 

6923: Particle Ionizer

October 1, 2019August 13, 2023 Master Builder

Year Released: 1990BricklinkInstructions (Revision/Addition: P12, Step 17) *Alternate Build Connection: 6862: Secret Space Voyager

6545: Search N’ Rescue
Classic Town Large Builds Official Sets Police Town Town Sets 

6545: Search N’ Rescue

June 2, 2022June 2, 2022 Master Builder
4504: Millennium Falcon (Redesign)
Episode IV/V/VI Extra Large Builds Official Sets Star Wars Star Wars Sets 

4504: Millennium Falcon (Redesign)

May 15, 2023May 15, 2023 Master Builder
6651: Post Office Van
Classic Town Official Sets Post Office Small Builds Town Town Sets 

6651: Post Office Van

February 3, 2021February 3, 2021 Master Builder
6390: Main Street
Box Marketing Blurb Classic Town Extra Large Builds Official Sets Town Town Sets Traffic 

6390: Main Street

February 10, 2023April 3, 2024 Master Builder
1590-2: ANWB Breakdown Assistance
Classic Town Large Builds Official Sets Town Town Sets Traffic 

1590-2: ANWB Breakdown Assistance

October 22, 2021October 22, 2021 Master Builder
6207: A-wing Fighter
Episode IV/V/VI Medium Builds Official Sets Star Wars Star Wars Sets 

6207: A-wing Fighter

February 1, 2024February 1, 2024 Master Builder
6824: Space Dart I
Classic Space Classic Space Sets Official Sets Very Small Builds 

6824: Space Dart I

September 30, 2019October 6, 2019 Master Builder
6615: Eagle Stunt Flyer
Airport Classic Town Official Sets Small Builds Town Town Sets 

6615: Eagle Stunt Flyer

January 5, 2022January 5, 2022 Master Builder
7180: B-wing at Rebel Control Center
Episode IV/V/VI Large Builds Official Sets Star Wars Star Wars Sets 

7180: B-wing at Rebel Control Center

August 17, 2023August 17, 2023 Master Builder
6473: Res-Q Hovercraft
Large Builds Official Sets Res-Q Town Town Sets 

6473: Res-Q Hovercraft

January 20, 2022January 20, 2022 Master Builder
6817: Beta Buzzer
ABCs Insectoids Insectoids Sets Official Sets Space Very Small Builds 

6817: Beta Buzzer

June 1, 2022March 22, 2025 Master Builder
6876: Alienator
ABCs Bjarne Tveskov Blacktron Blacktron Sets Official Sets Small Builds Space 

6876: Alienator

November 16, 2019October 16, 2024 Master Builder
6125: Sea Sprint 9
Aquanauts Aquazone Aquazone Sets Jørn Thomsen Official Sets Very Small Builds 

6125: Sea Sprint 9

April 9, 2020July 29, 2023 Master Builder
6645: Street Sweeper
Classic Town Official Sets Small Builds Town Town Sets Traffic 

6645: Street Sweeper

November 20, 2020November 20, 2020 Master Builder
6357: Stunt ‘Copter N’ Truck
Classic Town Medium Builds Official Sets Town Town Sets Traffic 

6357: Stunt ‘Copter N’ Truck

January 28, 2022January 28, 2022 Master Builder

BOXES

INSTRUCTIONS

FAVORITES

MINIFIGS

About This Site

Logo
There were once pictures of additional LEGO® builds on the back of set boxes. Written on the boxes was typically something about the endless building possibilities, "Build any of these exciting models with this set!" There were no instructions for these alternate builds, until now.

Sets

  • Adventurers
  • Aquazone
  • Belville
  • Building Set with People
  • Castle
  • Duplo
  • Fabuland
  • Harry Potter
  • Holiday and Event
  • LEGOLAND
  • Model Team
  • Pirates
  • Space
  • Star Wars
  • Technic
  • Town
  • Universal Building Set
  • Western
  • More Sets
  • Misc

Useful Links

  • Submit Instructions!
  • New Instructions
  • New Official Sets
  • New Alternate Builds
  • Minifigs
  • Very Small Builds (<35 pcs)
  • Small Builds (<100 pcs)
  • Medium Builds (<200 pcs)
  • Large Builds (<400 pcs)
  • Extra Large Builds (>400 pcs)
  • How BOTBB was Built

In Honor of 1526

The classic space set that never was.

Copyright © 2026 Back of the Box Builds. All rights reserved. LEGO® is a trademark of the LEGO Group of companies which does not sponsor, authorize, or endorse this site.