Kenwood NXR-700 Service Manual page 44

NXR-700
■ Traceability Procedure of IC17 (Flash Memory of RF control MPU)
Confi rmation of Power Source Voltage
Test Point Normal Output Voltage
IC329 (pin 5)
Correct condition
Confi rmation of Reset control
Test Point Normal Control Voltage
R137
(either end of R137 is OK)
Correct condition
Parts other than IC17 are malfunctioning.
■ Traceability Procedure of IC325 (The Modem control MPU)
Confi rmation of Power Source Voltage
Test point Normal output voltage
IC15 (pin 3)
Correct condition
Confi rmation of Clock frequency
Test Point Proper Frequency
R566 14.7456MHz
(either end of R566 is OK)
Correct condition
Confi rmation of Reset control
Test Point Normal Control Voltage
IC303 (pin 1)
Correct condition
Parts other than IC325 are malfunctioning.
44
TROUBLE SHOOTING
3.3VDC
3.3VDC
3.3VDC
3.3VDC
Abnormal
Confi rmation of IC329 (pin 5) output.
condition
Remove R159 and if 3.3VDC, one of IC17, IC34,
IC28, IC32, IC33, or IC40 is malfunctioning.
Confirmation of the clock and reset control of
Abnormal
IC34
condition
Confi rmation of clock frequency:
If 14.7456MHz cannot be confi rmed at the edges
of R195:
X1 is malfunctioning or the circuit around X1 is mal-
functioning.
If the clock oscillation amplitude is weak at the
edges of R195, the drive circuit in IC34 is malfunc-
tioning.
Reset control confi rmation
Remove R232 and then confi rm the voltage of the
pad on the opposite side of IC34.
If 3.3VDC, IC34 is malfunctioning.
If both Clock and Reset control are working prop-
erly, one of IC17, IC28, IC32, IC33, or IC40 is mal-
functioning.
Abnormal
condition
Confi rmation of IC15 (pin 3) output
Remove R484. If 3.3VDC, IC325 is malfunctioning.
If the oscillation of 14.7456MHz cannot be con-
fi rmed:
Abnormal
X301 is malfunctioning or the circuit around X301 is
condition
malfunctioning.
The clock oscillation amplitude is weak:
The drive circuit in IC325 is malfunctioning.
Abnormal
Remove R559 and confirm the voltage on the
condition
pad at the reverse side of IC325:
If 3.3VDC, IC325 is malfunctioning.