Trouble Shooting
Page 15
NEC-FA150ATUA
11. Checking the DC/DC converter circuit
Checking the 5V is input from P306
pin 7 and pin 8.
Is the 5V input to I312 pin 3
O K
N G
Failure Point
Printed wire or components broke
between P306 pin 7,8 and I312 pin 3
Is the 3.3V output from I312 pin 2
O K
N G
Is the 3.3V input to I311 pin 1 and 3
O K
N G
refer to section 10 "No Power On"
Failure Point
1) I312 failure
2) I312 output circuit short to ground
O K
N G
Failure Point
Printed wire or components broke
between I312 output to I311 input
Is the 2.5V output from I311 pin 7 and 8
O K
N G
Failure Point
1) does I311 pin 4 puller up to 3.3V
2) I311 Failure
3) I311 output circuit short to ground
Printed wire broke between I311
output and ASIC circuit