Trouble Shooting
Page 17
NEC-FA150ATUA
13. Checking the audio circuit
Is a cable with the
host PC connected?
O K
N G
Failure point
Audio cable disconntction.
Aren't the setups of the
host PC a minimum and off?
O K
N G
Failure point
The setup of the host PC is changed.
Is correct output waveform
being inputted from J301
pin 2, 3 of the host PC?
O K
N G
Is the waveform which is the
same as J301 being
inputted to I314 pin 4, 9?
Failure point
Audio cable disconntction.
O K
N G
Failure point
1) Printed wire broke between J301 pin 2, 3 and I314 pin 4, 9.
2) R374, R376 open.
3) R378, R379 short.
4) C464, C465 open.
Is output wavefrom being
outputted in I314 pin 14, 17?
O K
N G
Is 12V supplied to I314 pin 15, 16?
O K
N G
Failure point
1) Speaker cable disconnection
2) Speaker failure
Proceed section 10
"Checking the No power on".
Is mute Low level at pin 12.
O K
N G
Proceed section 12 "Checking
the operation of CPU".
Is Variable DC volume
control at pin 6.
O K
N G
Proceed section 12 "Checking
the operation of CPU".
Failure point
I314 failure.