Damaged or malfunctioning components may cause your Form 4 or Form 4L printer to experience display issues. In cases where the printer powers on normally but the touchscreen is not behaving as expected, the issue is usually caused by a problem with the touchscreen or the touchscreen ribbon cable.

• Flickering or horizontal smearing on display
• Dimmed screen
• Multiple screens overlapping or ghost images
• Corners darker or lighter than normal
• Unresponsive touchscreen
• Vertical lines on display

• Faulty or damaged touchscreen
• Faulty or damaged ribbon cable
• Transient glitch

1. Power cycle the printer. Confirm that the motors move when the printer initializes and that the machine is otherwise functional. If the printer does not appear to power on or shows no signs of activity, follow the troubleshooting steps in the article Printer does not turn on (Form 4 and Form 4L generation).
2. If the touchscreen is on but is unresponsive or displaying images incorrectly, check the touchscreen ribbon cable’s connection to the touchscreen. Unplug the ribbon cable from the touchscreen, then reconnect it. Follow the instructions in the guide for replacing your printer’s touchscreen assembly:
• Replacing the Form 4 touchscreen assembly
• Replacing the Form 4L touchscreen assembly
3. If the ribbon cable has obvious damage, replace it following the same guide. Replacement touchscreen ribbon cables are available for purchase on the Formlabs Store:
• Form 4 touchscreen ribbon cable
• Form 4L touchscreen ribbon cable
4. If the ribbon cable is undamaged but reseating it does not fix the issue, replace the touchscreen and the ribbon cable. The two components are sold separately, and both are available for purchase on the Formlabs Store:
• Form 4 touchscreen ribbon cable
• Form 4 touchscreen assembly
• Form 4L touchscreen ribbon cable
• Form 4L touchscreen assembly
5. If the issue persists, contact Formlabs Support or your authorized reseller. Include a video showing the touchscreen’s behavior with your message.