Checking The Dc/Dc Converter Circuit - NEC -FA150ATUA Service Manual

11. Checking the DC/DC converter circuit

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