Why does keypad display board display abnormal?

Possible fault sources:

a.Flat cable between keypad display board and mainboard is loosened or damaged

b.Keypad display board malfunctions

c.Mainboard works abnormally

d.Programs are garbled

Recommended solutions:

a.Plug again or replace the flat cable

b.Maintain or replace the keypad display board

c.Maintain or replace the mainboard

d.Replace the program chip, and write in the program over again