Display works but buttons do not respond or only some buttons work intermittently.

Safety first: Unplug before removing the control panel.

Clean and dry:

• Remove the control panel bezel and gently lift the keypad membrane.
• Clean the contact areas with isopropyl alcohol and a lint-free cloth.
• Allow to dry completely before reassembly.

Check connections:

• Inspect the ribbon cable between the keypad and main board; reseat it firmly.

When to replace:

• If specific buttons remain non-functional, replace the keypad / user interface board.