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Trouble Shooting
NEC-FA150ATUA
12. Checking the operation of CPU
Is the +3.3V supply on CPU of I306
O K
N G
Failure point
Printed wire broke between I306 and I312 output circuit
Is 10MHz clock input to I306 pin 11
and 12 at TTL level
O K
N G
Failure point
X302 failure.
Check the Reset circuit after CPU 3.3V
stable than I306 pin 10 delay more than
20ms Low level stage and from Low
level change to 3.3V High level
O K
N G
Failure point
1) Printed wire broke between I306 pin 10 and I309 pin 6 output circuit
2) I309 failure
I306 failure.