The Form 4L power supply is located behind the back panel and powers the printer. A broken or malfunctioning power supply prevents the printer from functioning.

Use this guide to replace the Form 4L power supply.

Estimated time: 30-40 minutes

Overview: Prepare the Form 4L and a dust-free workspace for replacing the power supply.

Step 1: Remove the build platform

Remove the build platform first to avoid dripping resin onto the Light Processing Unit (LPU).

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 and mixer

Unlatch the mixer and resin tank. Remove the resin tank and cover it with its lid. Set the tank aside on a clean, flat surface.

Step 4: Prepare the workspace

Clear a workspace around your printer. Ensure that the workspace is well-ventilated and free of dust.

Step 5: Clean the printer

Open the printer cover and clean any resin pooled on and around the LPU with non-abrasive wipes. Dampen the wipes with isopropyl alcohol if necessary to fully remove the resin.

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.

Overview: Remove the lower rear panel to access the power supply.

Step 1: Unplug the networking cables and Wi-Fi antenna

Disconnect the Ethernet and USB cables from the unit, if they are connected. Unscrew and remove the Wi-Fi antenna.

Step 2: Remove the lower rear panel screws

Use a 2 mm hex driver to remove the eight screws securing the lower rear panel to the printer. Set the screws aside.

Step 3: Remove the lower rear bumper screws

Use a 2.5 mm hex driver to remove the three screws securing the lower rear panel to the bumper. Set the screws aside.

Step 4: Remove the lower rear panel

Pull the lower rear panel directly away from the printer. Set the panel aside.

Overview: After removing the lower rear panel, remove the power supply.

Step 1: Remove the power supply assembly screws

Use a 2.5 mm hex driver to remove the three screws that secure the power supply to the printer. Set the screws aside.

Step 2: Gently slide the powder supply assembly out

Hold the power supply assembly by its mounting plate. Tilt the bottom of the power supply away from the printer. Gently slide the power supply assembly out of the printer. Take care while removing as the power supply assembly cables are still attached to the printer. Lay the power supply assembly down with the mounting plate on the workspace.

Step 3: Remove the power supply assembly cable harness screws

Use a 2 mm hex driver to remove the two screws that secure the power supply cable harness to the power supply assembly. Set the screws aside.

Step 4: Remove the power supply screw terminal screws

Using a Phillips or flat head screwdriver, pry off the plastic covers at the screw terminals labelled -V and +V. Set the plastic covers aside. Using a Phillips or flat head screwdriver, remove the five screws securing the cables to the screw terminals. Set the screws aside.

Step 4: Disconnect the power supply ring terminal cables

Disconnect the five ring terminal cables connected to the power supply.

Step 5: Remove the power supply mounting plate screws

Lean the power supply assembly against the printer to access the mounting plate screws. Use a 2.5 mm hex driver to remove the four screws that secure the power supply to the mounting plate. Set the screws aside.

Step 5: Remove the power supply

Lift the power supply from the mounting plate. Set the power supply aside for disposal with electronic waste.

Overview: After removing the power supply, install the replacement power supply.

Step 1: Align the replacement power supply

Align the replacement power supply with the screw holes in the mounting plate, ensuring that the power supply fans are on the same side as the power switch.

Step 2: Secure the replacement power supply

Thread one screw into each of the four screw holes in the mounting plate and replacement power supply. Use a 2.5 mm hex driver to tighten the screws until finger tight.

Step 3: Reconnect the ring terminal cables to the power supply

With the power supply laying flat on the workspace, slide the open end of the ring terminals under the square washer on their respective screws on the power supply. Ensure the colored cables are in the correct position. Do not pull on the wires.

• N: Blue cable
• L: Brown cable
• : Green and yellow striped cable
• -V: Black cables
• +V: Yellow cables

There is space for two ring terminals underneath the -V and +V screw terminals. Stack the two ring terminals for both of the black cables under the -V screw terminal. Stack the two ring terminals for both the yellow cables under the +V screw terminal.

Step 4: Secure the ring terminals to the power supply

Thread a screw through each ring and screw terminal. Use a Phillips or flathead screwdriver to tighten the five screws to secure the ring terminals to the power supply until finger tight. Snap the two plastic covers over the -V and +V screw terminals.

Step 4: Secure the power supply assembly cable harness

Thread one screw into each of the two screw holes in the power supply assembly cable harnesses. Using a 2 mm hex driver, secure the cable harnesses to the power supply.

Step 5: Position the power supply assembly

Angle the top of the power supply assembly towards the printer. Slide the top of the power supply assembly underneath the printer frame. Ensure the cables attached to the power switch and cable harness are fully seated and are not pinched between the power supply assembly and the printer frame.

Step 5: Push the power supply assembly into the printer frame

Gently push the power supply assembly into the printer until the bottom of the mounting plate is flush with the printer frame.

Step 6: Mount and secure the power supply assembly

Thread one mounting screw into each of the three screw holes. Use a 2.5 mm hex driver to tighten until snug.

Overview: Reinstall the lower rear panel and the Wi-Fi antenna.

Step 1: Replace the lower rear panel

Place the lower rear panel back onto the printer. Press it towards the front of the printer to ensure that it fully seats in place. There should be no gaps between the lower rear panel and the side or bottom shells.

Step 2: Secure the lower rear panel

• Use a 2 mm hex driver to secure the eight screws highlighted in red attaching the lower rear panel to the printer.
• Use a 2.5 mm hex driver to secure the three screws highlighted in yellow attaching the lower rear panel to the bumper.

Step 3: Plug in the networking cables and Wi-Fi antenna

Connect the Ethernet and USB cables to the unit, if needed. Screw in the Wi-Fi antenna.

Overview: After installing the replacement power supply, power on the printer and perform final checks.

Step 1: Power on the printer

Connect the power cable to the printer and the power supply. The printer initializes.

Step 2: Run a test print

Insert any missing consumables and run a test print. Check that the print starts normally and the parts print successfully. Contact Formlabs Support or your authorized reseller to share the results of the procedure.