Kenwood NXR-800H Service Manual

NXR-800H103■ Traceability Procedure of IC17 (Flash Memory of RF control MPU)Confirmation of Power Source VoltageTest Point Normal Output VoltageIC329 (pin 5) 3.3VDCCorrect conditionConfirmation of Reset controlTest Point Normal Control VoltageR137 3.3VDC(either end of R137 is OK)Correct conditionParts other than IC17 are malfunctioning.■ Traceability Procedure of IC325 (The Modem control MPU)Confirmation of Power Source VoltageTest point Normal output voltageIC15 (pin 3) 3.3VDCCorrect conditionConfirmation of Clock frequencyTest Point Proper FrequencyR566 14.7456MHz(either end of R566 is OK)Correct conditionConfirmation of Reset controlTest Point Normal Control VoltageIC303 (pin 1) 3.3VDCCorrect conditionParts other than IC325 are malfunctioning.Confirmation of IC329 (pin 5) output.Remove R159 and if 3.3VDC, one of IC17, IC34,IC28, IC32, IC33, or IC40 is malfunctioning.Confirmation of the clock and reset control ofIC34Confirmation of clock frequency:If 14.7456MHz cannot be confirmed at the edgesof R195:X1 is malfunctioning or the circuit around X1 is mal-functioning.If the clock oscillation amplitude is weak at theedges of R195, the drive circuit in IC34 is malfunc-tioning.Reset control confirmationRemove R232 and then confirm the voltage of thepad 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.AbnormalconditionAbnormalconditionConfirmation of IC15 (pin 3) outputRemove R484. If 3.3VDC, IC325 is malfunctioning.If the oscillation of 14.7456MHz cannot be con-fi rmed:X301 is malfunctioning or the circuit around X301 ismalfunctioning.The clock oscillation amplitude is weak:The drive circuit in IC325 is malfunctioning.Remove R559 and confirm the voltage on thepad at the reverse side of IC325:If 3.3VDC, IC325 is malfunctioning.AbnormalconditionAbnormalconditionAbnormalconditionTROUBLE SHOOTING