Osd Is Unstable Or Not Working - BenQ E2220HD Service Manual

21.5" LCD Color Monitor
Key Board

OSD is unstable or not working

Is Key Pad Board connecting normally?
Is Button Switch normally?
Is Key Pad Board normally?
Y
Y
Y
Check Main Board
N
Connect Key Pad Board
N
Replace Button Switch
N
Replace Key Pad Board
75
BenQ E2220HD