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Trouble Sh ooting
A LC502
11. Checking the operation of CPU
Is there +5.0V supply on I303 pin 44
OK NG
Failure point
Printed wire broke between output of FB320 and I300 power supply pin.
Is 12MHz clock input to I303 pin 21
and 20 at TTL level?
OK
NG
Failure point
X301 failure.
Check the input of 5V "H" pulse from
I310 pin 4 are same as I303 pin 10.
(14 msec Typ)
OK
NG
Failure point
1) Printed wire broke between I310 pin 4 and I303 pin 10.
I303 failure.