Kenwood NXR-700H Service Manual

NXR-700H99■ Traceability Procedure of IC323 (RX_DSP)Confirmation of Power Source VoltageTest Point Normal Output VoltageIC307 (pin 1) 1.5VDCIC15 (pin 3) 3.3VDCCorrect conditionConfirmation of Clock frequencyTest Point Proper FrequencyR678 12.288MHz(either end of R678 is OK)Correct conditionConfirmation of Reset controlTest Point Normal Control VoltageR521 3.3VDC(Either end of R521 is OK.)Correct conditionParts other than IC323 are malfunctioning.■ Traceability Procedure of IC314 (Flash Memory of modem control MPU)Confirmation of Power Source VoltageTest Point Normal Output VoltageIC15 (pin3) 3.3VDCCorrect conditionConfirmation of Reset controlTest Point Normal Control VoltageIC303 (pin 1) 3.3VDCCorrect conditionParts other than IC314 are malfunctioning.Confirmation of IC307 (pin 1) outputRemove R505. If the output voltage is 1.5VDC,IC323 is malfunctioning.Confirmation of IC15 (pin 3) output.Remove R487. If the output voltage is 3.3VDC,IC323 or IC327 is malfunctioning.If 12.288MHz oscillation cannot be confirmed:X300 is malfunctioning or a component aroundX300 is malfunctioningThe clock oscillation amplitude is weak:The circuit around X300 is malfunctioning.Remove R521 and then confirm the voltage atthe pad side of IC325:If not 3.3VDC, IC325 is malfunctioning.Remove R521 and confirm the voltage on thepad side of IC325:If not 3.3VDC, IC323 is malfunctioning.AbnormalconditionAbnormalconditionAbnormalconditionAbnormalconditionAbnormalconditionConfirmation of IC15 (pin 3) output.Remove R417. If 3.3VDC, IC314 is malfunctioning.Confirmation of IC303 (pin 1) output voltageIf equal to or less than 3.3VDC, IC303 is malfunc-tioning.Remove R470 and confirm the voltage of IC303(pin 1).If 3.3VDC, IC314 is malfunctioning.TROUBLE SHOOTING