for Bambu Lab Toolhead Board - A1 Series

The Toolhead Board is the main circuit board of the toolhead which provides connectivity to the toolhead parts, including the hotend heating assembly, extruder unit, hotend cooling fan, filament sensor, etc.

Installation

Learn more about replacing the Toolhead Board on Bambu Lab Wiki.

In the Box

1. Toolhead Board * 1
2. M2-2 Screws * 4

Compatibility

A1 Series

Product Specifications

TH Board Replacement Guide - A1

This guide shows how to replace the TH Board on the A1

In this guide, we will show how to replace the TH Board on the A1.

Note: The new version of the TH board is missing two terminals (circled in red), leaving only the solder pads.

When to use?

This guide is intended for use if there is a problem with the TH Board.

Common issues that may indicate the need for replacement of the A1 TH Board include:

Problems with bed leveling, where the nozzle doesn't accurately perform the homing procedure

The extruder motor is not turning as expected, due to a potentially faulty stepper driver

The USB C connector is damaged

The Filament Sensor ribbon cable connector is damaged
The Heater connector is damaged

The tool head is not detected, and an error message is displayed on the printer screen

Recommended by Bambu Lab Technical Support

Tools and materials needed

Bambu Lab Toolhead Board for A1

H2.0 hex wrench
H1.5 hex wrench
15 minutes of your time

Remove the Old TH Board

1. Remove the back printhead cover

The first step in replacing the faulty TH Board is to remove the back cover of the toolhead.

Carefully pry open the back cover by pulling on the bottom section as shown below.

2.Remove the USB-C cable from the toolhead

Next, remove the four screws holding the USB-C cable secure on the toolhead of the A1.

After removing the screws, the USB-C cable can be pulled upwards to remove it.

3. Remove the TH Board screws

Remove the three black screws holding the TH Board in place.

4. Disconnect the cables

Next, remove the four cables attached to the TH Board.

Carefully pull them out by the connector, and avoid pulling the wires from the connectors.

We recommend using a flat tool to gently pry them out to avoid any potential damage.

Don't forget to also remove the Eddy sensor wires which are held in place by two screws.

5. Remove the TH Board

You can now remove the TH Board from the plastic housing.

First, open the clip that fixes the cable in place. Then you should be able to disconnect the cable.

Be careful when pulling it out, as you will need to carefully disconnect the filament sensor ribbon cable.

Pull it slowly and straight upwards. Avoid wiggling the ribbon cable as it can cause damage to it. If you have damaged it, you can order a replacement from this link Filament Sensor - A1 Series | Bambu Lab US Store

Install the New TH Board
1. Attach the TH Board to the housing

The first step in installing the new TH Board is to attach it back on the toolhead housing.
Before inserting the cable, remember to flip up the latch of the connector. The latch is designed to lock the cable in place. Gently lift the latch, insert the cable fully into the slot, and then press down the latch to secure the connection.

Carefully route the Extruder Motor cable next to the ribbon cable as shown in the image below.

After this step is done, you can gently push the TH Board back in its position.

2. Install the TH Board screws

Use the three black screws to re-attach the TH Board back to the toolhead.

Important!
Do not overtighten the screws to avoid any potential damage.

3. Re-connect all the cables

With the new TH Board back in its original position, you can re-connect all the wires as shown below.

1. Hotend Heating Assembly
2. Extruder Motor
3. Hotend Cooling Fan
4. Part Cooling Fan

5. Hotend Sensor4. Re-connect the USB-C cable

Re-install the USB cable using the four screws we removed in the first step, while being careful about the orientation.

Important!

Do not over-tighten these screws, as the threads can damage the plastic. 

Take note of the USB-C cable orientation and the small groove from the back that aligns it.

The USB-C cable only fits in one position, with the correct orientation having the line in the cable connector aligned to the back of the printer and toolhead.

5. Install the toolhead back cover

Finally, install the back cover of the A1 toolhead.

The back cover clips in place. Simply align the two brackets on the back cover towards the top, then push it until you hear a few clicks.

Verify the Functionality
Check the indicator lights on the control board

Normal State: the TH board indicator light is constantly green

Carefully pry open the back cover by pulling on the bottom section as shown.Calibration step after the operation

We recommend conducting a full calibration of the printer after this operation.

Additionally, it's strongly advised to wash the PEI textured plate before use, as it may have been contaminated during this process.

Potential problems and solutions

If you encounter problems during the installation of a new Toolhead Board, please check the potential problems and solutions listed below:

The hotend temperature is 0

Check the Hotend Heating Assembly connector and confirm it is correctly inserted, as shown in Step 3. Re-connect all the cables
It is important to carefully align the connector pins to the Toolhead Board.
If the issue persists, the thermistor wires might have been damaged (White wires)

The hotend cannot be heated

Check the Hotend Heating Assembly connector and confirm it is correctly inserted, as shown in Step 3. Re-connect all the cables
It is important to carefully align the connector pins to the Toolhead Board.
If the issue persists, the heater wires might have been damaged (Translucent wires)

Printer is not homing correctly

Check the Eddy Sensor wires (5 and 6) and confirm they are correctly installed on the back of the Toolhead Board, as shown in Step 3. Re-connect all the cables

Filament sensor is not working

Check the Ribbon Cable and confirm it is correctly installed on the back of the Toolhead Board, as shown in Step 1. Attach the Toolhead Board to the housing
If the ribbon cable is damaged, you will need to replace the Filament Sensor.

A1 Mini TH Board Connectors

1.Hotend Heating Assembly Connector

2.Filament Sensor Ribbon Cable Connecto

3.USB-C Connector

4.Extruder Motor Connector

5.Hotend Cooling Fan Connector

6.Eddy Sensor Connector

7.Part Cooling Fan Connector