S1 Plus Gearbox Replacement Guide

Overview

Each S1 gearbox is built similarly to a 3D printer extruder. Positioned just before the drive gears is a built-in filament runout switch—this sensor detects whether filament is present or empty on that side of the S1. These runout switches are connected to the main PCB via a 2-wire cable (red and black).

This switch is critical to the S1’s automatic reload system, allowing the device to monitor each spool independently and trigger a seamless filament handoff when one side runs out.

Gearboxes and other replacement parts can be purchased separately.

Removing the Filament Junction

1. Remove the S1 Roller sides using this guide.

2. Disconnect Lower Bowden Tubes from the S1 Plus and set them aside

3. Remove the filament junction cover by lightly squeezing the cover and pulling it off of the S1.

4. Remove the three philips screws holding the cover on

5. Carefully lift the case off—it should come off easily.

6. Disconnect the Gearbox runout switch wire.

7. Unscrew the Gearbox from the S1 Plus and remove it.

Installing the Filament Junction

1. Line up the motor and the gearbox on the S1 Plus Frame.

2. Install the three long M3 screws holding on the Gearbox.

3. Plug in the filament runout switch.

4. Carefully place the cover back on, ensuring that wires fit into designated slots (shown in image below).

5. Secure the three screws back into place to hold on the cover.

6. Snap the filament junction cover back into place

7. Reinstall the Lower tubes of the S1

8. Install the roller sides using this guide.