Kenwood NXR-700H Service Manual

NXR-700H103■ Traceability Procedure of IC34 (The RF controlMPU)Confirmation of Power Source VoltageTest Point Normal Output VoltageIC16 (pin 5) 5VDCIC329 (pin 4) 3.3VDCCorrect conditionConfirmation of Clock frequencyTest Point Proper FrequencyR195 14.7456MHz(either end of R195 is OK)Correct conditionConfirmation of Reset controlTest Point Normal Control VoltageIC303 (pin 1) 3.3VDCCorrect conditionParts other than IC34 are malfunctioning.1-3. Hardware Traceability (Method 2)The NXR-700H control circuit executes the following pro-cedures when the system starts up.1. An external DC 13.2V power source is applied to theNXR-700H terminal.2. The Modem control MPU (IC325) starts up.3. The Modem control MPU (IC325) initiates all circuitblocks.4. The Main MPU (IC703) and the RF control MPU (IC34)start up.Confirmation of IC16 (pin 5) outputRemove R201. If 5 VDC, IC34 is malfunctioning.Confirmation of IC329 (pin 4)Remove R159. If 3.3 VDC, IC34 or IC17 may bemalfunctioning.If the oscillation of 14.7456MHz cannot be con-fi rmed:X1 is malfunctioning or the circuit around X1 is mal-functioning.Clock oscillation amplitude is weak:Drive circuit in IC34 is malfunctioning.Remove R332 and confirm the voltage of thepad on the opposite side of IC34:If 3.3 VDC, IC34 is malfunctioning.AbnormalconditionAbnormalconditionAbnormalcondition5. The Main MPU (IC703) confirms the operational status ofthe Modem control MPU (IC325) and the RF control MPU(IC34) by using 115.2kbps UART communications andthen the operation transfer commands will be exchangedin order to integrate all hardware blocks.The above steps 1 to 5 will be executed as follows.TROUBLE SHOOTING