DIAGNOSIS The firmware has crashed or become corrupted, often from a low-power state or interrupted update.
FIX Perform a hard reset. 1. Disconnect the power cable from the printer. 2. Press and hold the printer's power button for 15 seconds (with no power connected). 3. While still holding the button, reconnect the power cable. 4. Keep holding for another 5 seconds, then release. 5. Press the power button normally to turn it on. This should force a reboot and clear the display.
IF THAT DIDN'T WORK The display ribbon cable might be loose. This requires opening the case—only attempt if you're comfortable. Contact JADENS support first, as this may be a hardware fault covered under warranty.
HEADS UP Always use the provided power adapter. Using a USB cable with a phone charger block that doesn't provide consistent 5V/2A power can cause these firmware glitches during operation.