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LEGO Missing Piece Checker

Rule out the usual hiding places first. If the piece really is gone, check the set piece by piece and leave with the element ID LEGO asks for, or a link to buy the part.

Robotics Invention System Upgrade Kit (1.5)

Checking

3803 Robotics Invention System Upgrade Kit (1.5)

70 pieces in 25 part and color combinations.

Before you call it missing

Builders who report a missing piece often find it in one of these places. Tick each one off as you look.

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Piece checklist

Light Gray 31 pieces

  • Plate 2 x 2 Corner Light Gray Part 2420 Element 242052 or 242002 ×8
  • Plate Special 2 x 2 with 2 Pin Holes Light Gray Part 2817 Element 281702 ×2
  • Technic Axle Connector Ridged [with x Hole x Orientation] Light Gray Part 6538b Element 4113804 or 4100408 ×2
  • Technic Axle and Pin Connector Perpendicular Light Gray Part 6536 Element 4173667 or 653602 ×8
  • Technic Beam 1 x 3 Thin Light Gray Part 6632 Element 4107825 ×2
  • Technic Beam 1 x 5 Thin Light Gray Part 32017 Element 4106885 ×2
  • Technic Beam 3 x 3 L-Shape Thin Light Gray Part 32056 Element 4111941 ×4
  • Technic Bush 1/2 Smooth with Axle Hole Reduced Light Gray Part 32123a ×3

Black 21 pieces

  • Rubber Band Small 13mm (Square Cross Section) Black Part 71509 Element 4141606 or 4107153 ×2
  • Technic Axle 2 Notched Black Part 32062 Element 4109810 or 3206226 ×2
  • Technic Axle 4 Black Part 3705 Element 370526 ×4
  • Technic Axle 5 Black Part 32073 Element 4114740 ×2
  • Technic Axle 6 Black Part 3706 Element 370626 ×2
  • Technic Axle 8 Black Part 3707 Element 370726 ×1
  • Technic Beam 1 x 7 Thin Black Part 32065 Element 6271573 or 6253293 ×4
  • Technic Beam 1 x 9 Bent (6 - 4) Thick Black Part 6629 Element 6279881 or 4119800 ×2
  • Technic Beam 2 x 4 L-Shape Thick Black Part 32140 Element 6271825 or 4120017 ×2

Blue 8 pieces

  • Technic Axle and Pin Connector Angled #2 - 180° Blue Part 32034 Element 6484676 or 4107798 ×2
  • Technic Pin Long with Friction Ridges Lengthwise and Stop Bush [3 Lateral Holes, Big Pin Hole] Blue Part 32054 Element 4140800 or 4107741 ×4
  • Technic Rubber Belt Medium [26mm ID] [Round Cross Section] Blue Part 85545 Element 6049730 or 4544147 ×2

Trans-Dark Blue 4 pieces

  • Technic Modular Connector Trans-Dark Blue Part 32137 Element 4118978 ×4

White 3 pieces

  • Rubber Belt Small [15mm ID] [Round Cross Section] White Part 85543 Element 6699001 or 4580665 ×2
  • Technic Gear 24 Tooth Clutch with Dark Gray or Light Gray Center White Part 76019 Element 4270486 ×1

Yellow 2 pieces

  • Technic Pin Double with Axle Hole Yellow Part 32138 Element 4130596 or 4119438 ×2

[No Color/Any Color] 1 piece

  • Sticker Sheet for Sets 3803-1, 9732-1 [No Color/Any Color] Part 72047 Element 4112924 ×1

Tick each piece as you find it, or mark it missing.

When a piece really is missing

Ask LEGO

LEGO takes requests for pieces missing from a new set through its customer service site. The form asks for the set number and each piece's element ID, the number printed beside the piece in the parts list at the back of the instructions. This checker lists both.

Request a replacement from LEGO

Buy the piece

Mark a piece missing and your list links it to an eBay search for that part, which also covers pieces from older or second-hand sets.

Keep a record

Copy or download your missing list (the CSV opens in any spreadsheet), or print the whole checklist and tick pieces off on paper. Your marks stay in this browser, so you can check a big set over several sittings.

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