1-66 (No.RA016)5.2 Failure diagnosis of the GPS sectionOverview:When the GPS fuction does not operate, use this flowchart to determine the problem.Positioning is not carried out normally.Suitable location for the receive theGPS signal ?Verify the contact of the GPS internal antennawith the PCB.NoYesGPS antenna (Connect on CN907)LNA IC (IC851)Pre-SAW Filter (L857)Post-SAW Filter (L853)Bluetooth/GPS IC (IC850)Level conversion IC (IC852, IC853)TCXO 19.2MHz (X700)Clock Buffer (IC700)32.769 KHz clock (X850)33BT Regulator (IC38)18BT Regulator (IC37)MPU/DSP IC (IC702)Re-assembling the GPS antennacorrectly.If an antenna is defective, replace theGPS internal antenna.Replace any abnormal parts.Verify the BT/GPS powersupply.IC702 IC852 IC850 L857 Shee t metalUART UARTIC853 L853 IC851PCM PCMLNAX700 IC700 X850MPU/DSPIC BT/GPSICTCXO19.2MHz32.768 kHzClockANTMatchingGPSAntenn aClockBufferLevelconversionICLevelconversionICHPFPre-SAWFilterPost-SAWFilterRFMatching ATTOperate at place where is good visibilityof the sky.Check the PCB side A.Check the PCB side A.Verify the ANT Matching Parts.Verify check to L905, C948, C883.[The BT/GPS power supply line33BT circuit is faulty]Verify the PCB side A parts.C856, C860, C861, C870, L862,C885, C890Replace any abnormal parts.Check the PCB side B (a).Verify the BT/GPS powersupply.[The BT/GPS power supply line18BT circuit is faulty]Verify the PCB side A parts.C859, C852, C868, L861, C891, C844Check the PCB side B (b).Verify the BT/GPS controlsignal (/BT_SHUTDOWN). [MPU/DSP (IC702) is faulty]Replace the PCB.(33BT) L862: 3.3V(18BT) L861: 1.8VR853: 1.8VWhen an abnormalcondition is confirmed.When an abnormalcondition is confirmed.When an abnormalcondition is confirmed.When an abnormalcondition is confirmed.When an abnormalcondition is confirmed.When an abnormalcondition is confirmed.When an abnormalcondition is confirmed.When a normalcondition is confirmed.When a normalcondition is confirmed.When a normalcondition is confirmed.When a normalcondition is confirmed.When a normalcondition is confirmed.Major parts for a GPS circuit
