When Key does not operate
P911A output normal?
Check Start
Y
Does LED turn on
in Red?
Y
Does LED turn on
in Green?
Y
Is 1st and 3rd pin of
Y
Check main PCB
N
1. Confirm AC connection
2. Confirm Power S/W ON
N
1. Check the connection to main PCB.
2. Check the main PCB or Sub PCB.
N
Key PCB has a trouble.
So, exchange Key PCB.