Casio SF-4300R Service Manual & Parts List page 18

1
Is 1-Pin of S-80752AN (DET 1) 5[V]?
Y
Is 11-Pin of CPU (LSI 1) sending the
signal?
Y
Is 13-Pin of CPU (LSI1) sending
the signal?
Y
Does RAM or ROM (for LX-546AQ)
make positive contact with PCB?
Y
Replace RAM (LSI3) or ROM (LSI4) or CPU (LSI1)
< No key input >
Does key make positive contact with PCB
Ass'y
Y
Does CPU make positive contact with PCB?
Y
Replace CPU (LSI1)
N
Replace DET1
N
Replace CPU (LSI1)
N
Replace CPU (LSI1)
N
Resolder RAM (LSI3) or ROM (LSI4)
N
Replace PCB
N
Resolder CPU (LSI1)
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