Microwave shows E19 and the charcoal or grease filter indicator will not reset (over-the-range models).

Safety: No internal high-voltage work is required for this issue, but unplugging is still recommended before removing the control panel.

Steps:

• 1. Perform proper reset: After replacing or cleaning the filter, follow the Sharp manual procedure (often holding the FILTER or 0 key for several seconds) to reset the indicator.
• 2. Power cycle: Unplug the microwave for 2–3 minutes, then reconnect and attempt the reset again.
• 3. Check keypad function: Verify that the button used for reset responds normally in other functions. If that key is unresponsive, the keypad may be faulty.

Repair: If E19 persists and the keypad is functional, the control board's filter timer circuit may be defective and require replacement.