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Replacing the Form 3L LevelSense board

The LevelSense board senses the amount of resin in the resin tank. The LevelSense board sits at the back-right of the printer, pointed downward at the corner of the resin tank. A malfunctioning LevelSense board prevents the printer from printing properly.

Formlabs recommends removing the LevelSense board from the front as it is significantly faster. However, accessing the LevelSense board through the rear of the printer may be necessary if you cannot unplug or reconnect the LevelSense cable from the front.

Use this guide to replace the Form 3L LevelSense board.

Required Supplies:

Formlabs:

LevelSense board

Third-party:

M3 (2 mm) hex driver or L-shaped hex key
Adhesive tape
Nitrile gloves
Flexible 5.5 mm nut driver (optional)
T8 or T10 Torx driver (optional, if removing the rear shell)

Estimated time: 20–30 minutes

DANGER:

Read and follow all safety instructions and warnings in the operator manual. Replacement with incorrect parts can lead to burns, shock, fire, or explosion. Dispose of all parts in accordance with local regulations.

Preparing the workspace

Overview: Prepare the Form 3L and a dust-free workspace for replacing the LevelSense board.

NOTICE:

The LevelSense board is a sensitive electronic component. Do not remove the LevelSense board from its packaging until instructed.

Step 1: Remove the build platform

Remove the build platform first to avoid dripping resin onto the LPU or into the printer cavity.

Step 2: Remove the resin cartridges

Remove the resin cartridges and close the vent caps to prevent resin from dripping off of the bite valves and into the printer.

Step 3: Remove and store the resin tank

Remove the resin tank, place it in the resin tank case, and cover it with its lid. Set the case and tank aside on a clean, flat surface.

NOTICE:

Wear gloves and hold the resin tank by the tank grips on either side to avoid contamination or damage to the underside of the tank.

Step 4: Prepare the workspace

Clear a workspace around your printer. Ensure that the workspace is well-ventilated and free of dust. Prepare additional space for storing the rear panel of the printer during maintenance.

Step 5: Clean the printer cavity

WARNING:

Resin may cause skin irritation or an allergic skin reaction. Wear gloves when handling liquid resin or resin-coated surfaces. Wash skin with plenty of soap and water.

Open the printer cover. Clean any resin pooled on the printer floor inside the printer cavity with paper towels. Dampen the paper towels with isopropyl alcohol if necessary to fully remove the resin.

DANGER:

Fire hazard. IPA is flammable. Keep containers closed, and keep out of the reach of children.

Step 6: Unplug the printer

Disconnect the power cable before continuing with maintenance. Do not perform maintenance on the printer while it is connected to power. Wait five minutes after disconnecting the printer from power before proceeding.

DANGER:

Performing maintenance on the printer while it is plugged in increases the risk of electric shock. Never remove the back panel of the printer while the printer is plugged in. Never reconnect the printer to power while the back panel is uninstalled.

Removing the LevelSense board

Overview: Unplug, unscrew, and remove the LevelSense board from the printer.

DANGER:

The Form 3L contains sensitive electronic components. Ground yourself before touching any electronics in the printer by using a grounding strap or touching a grounded piece of metal.

Step 1: Locate the LevelSense board

Locate the LevelSense board, positioned at the back-right of the printer cavity. There is a trapezoidal metal shroud protruding from the rear wall of the printer, directly above the resin tank. The LevelSense board is attached to the underside of this shroud.

Step 2: Unscrew the LevelSense board

Using the M3 (2 mm) hex driver, unscrew and remove the four screws holding the LevelSense board in place. Set aside the screws for later use.

TIP:

Be careful not to drop the screws into the rear of the machine. Formlabs recommends using a magnetic hex driver or an L-shaped hex key due to spatial constraints.

Dropped screws can be retrieved by removing the rear shell.

Step 3: Pull the LevelSense board forward

Gently pull the LevelSense board forward to gain more slack in the LevelSense cable.

Step 4: Disconnect the LevelSense board

Grip the plug and disconnect the cable from the LevelSense board. Do not pull on the wires. Secure the cable to the printer cavity with adhesive tape to keep it from falling into the back of the printer. Remove the LevelSense board.

If you are having trouble removing the LevelSense board, Formlabs recommends accessing it from the rear of the machine by following the optional instructions below.

Removing the LevelSense shroud (optional)

DANGER:

The Form 3L contains sensitive electronic components. Ground yourself before touching any electronics in the printer by using a grounding strap or touching a grounded piece of metal.

Overview: Remove the rear shell, remove the LevelSense shroud, and slacken the LevelSense cable to make it easier to disconnect. If you have already removed the LevelSense board from the front of the machine, skip to the section Installing the new LevelSense board.

Step 1: Remove the Wi-Fi antenna nut

Unscrew and remove the nut from the base of the Wi-Fi connector. The Wi-Fi connector is attached to the printer’s motherboard and remains in place when the rear shell is removed.

Step 2: Remove the rear shell screws

Use a T10 or T8 Torx driver to loosen and remove the 21 screws on the rear shell. Early models may use all T8 screws, while later models use all T10 screws. Start at the bottom of the panel and work your way up to the top.

Step 3: Remove the rear shell

Remove the rear shell by pulling it away from the printer. There are five pins that hold the panel in place, so it may require moderate force to separate from the printer. Be careful not to damage the rear fan cable, which is still attached to the rear shell. Lay the rear shell down next to the printer.

Step 4: Disconnect the rear fan

Disconnect the rear fan cable harness by gripping the plugs and gently pulling them away from each other. Do not pull on the wires themselves.

Step 5: Unscrew the K-nuts beneath the LevelSense shroud

With a 5.5 mm nut driver, unscrew the K-nuts that secure the LevelSense shroud.

LevelSense shrouds may extend downwards in more recently manufactured printers. Formlabs recommends the use of a flexible 5.5 mm nut driver to access and remove the K-nut behind the LevelSense shroud. Set the K-nuts aside for later use.

Step 6: Remove the LevelSense shroud

Remove the shroud that protects the LevelSense board.

Step 7: Slacken the LevelSense cable

Pull gently upward on the cable attached to the LevelSense board. This provides some slack so that the cable is easier to disconnect.

Installing the new LevelSense board

Overview: After removing the old LevelSense board, connect and install the replacement LevelSense board.

Step 1: Reconnect the LevelSense cable

Plug the LevelSense cable into the LevelSense board. The cable will only enter the connector in the correct orientation. Be careful not to bend the pins in the connector.

Step 2: Mount and secure the LevelSense board

Position the replacement LevelSense board underneath the shroud, aligning the four screw holes in the board with the four screw holes in the mounting surface. Thread each of the four screws into the screw holes. Tighten the screws using the hex driver until finger tight.

Replacing the LevelSense shroud (optional)

Overview: If you installed the LevelSense board from the rear of the printer, replace the LevelSense shroud and the rear shell.

Step 1: Replace the LevelSense shroud

Replace the shroud that protects the LevelSense board.

Step 2: Reattach the K-nuts beneath the LevelSense shroud

With a 5.5 mm wrench, reattach the K-nuts that secure the LevelSense shroud.

Step 3: Connect the rear fan

Lay the rear shell down behind the printer. Reconnect the two ends of the rear fan cable.

Step 4: Replace the rear shell

Place the rear shell back onto the printer, taking care to align the five pins on the shell with their respective holes. Press it towards the front of the printer to ensure that it fully seats in place. There should be no gaps between the rear shell and the side or bottom shells.

Step 5: Secure the rear shell

Using a T8 or T10 Torx driver, screw the 21 screws into the rear of the printer.

Finalizing the repair

Overview: After installing the new LevelSense board, power on the printer and perform final checks.

Step 1: Power on the printer

Close the printer cover and connect the power cable to the printer and the power supply. The printer initializes.

Step 2: Update the printer’s firmware

Update the printer's firmware.

If the printer reports any errors, repeat this maintenance procedure and ensure that the LevelSense cable is fully plugged into the new LevelSense board. Contact Formlabs Support or your authorized reseller to share the results of the procedure.