Panasonic EB-X70 Service Manual

Also see for EBX70 - CELL PHONE: Operating instructions Operating instructions Technical information Service manual

FAULT FINDINGPMCD030901C8 Section 8 Issue 1Service Manual – 49 – Revision 08.3. Power on fault analysisThe handset uses underfill techniques on some components which renders them unserviceable. These components includeCALYPSO+ and SYREN. If these components are found to be faulty a replacement PCB will be required to repair thehandset.If the handset fails to power on, de-case the unit and place in the PCB repair jig. Check each stage of the power-on sequenceas detailed below.Signal Details Suspect Device FaultCodeSerial Port Ensure all connections are madecorrectly.Check using known ‘good’ phone.Supply Voltage Vbat should be 3.7 V. Check power supply or that battery isfully charged.System Clock Check that 13 MHz is present onbaseband.Check VCXO. IBaseband Voltages Check the voltage levels of A28V,D28VB, D28V, D18V, D20V, TP107-TP111.If levels are absent, suspect SYREN. JRTC 32 kHz clock 32 kHz clock signal applied toCALYPSO+. Check TP100.If levels are absent, suspect SYREN. LBattery Check Check resistance between T and minusterminal of battery.Resistance should be approx. 10K.Battery Charging Incorrect or not charging.The gate of FET Q100 (ICTL) should behigh.Check D100, Q100.Otherwise suspect SYREN. MONNOFF TPEH18 should be high. If signal absent, suspect SYREN. NPower-on sequence Test Point ExpectedOutput On failureVBAT is applied (> 2.6 V) TP330/TP3283.7 V Battery connector and associated circuits.Release of Master Reset TPEJ15 Active low If not present, suspect SYREN.Application of VRTC to 32 kHzRTCTP112 1.5 V If not present, suspect CALYPSO+.32 kHz clock runs TP100-1 32 kHz sine If not present, suspect crystal and CALYPSO+Power key is pressed TPA100 Active low If not present, suspect keyswitch.Power ON/OFF signal toCALYPSO+ and memoryregulator.TPEH18 2.2 V activehighIf not present, suspect keyswitch.SYREN powers voltage TP107 1.5 V DC CALYPSO+ internal supplyregulators TP108 2.8 V DC Accessory supply SuspectTP109 2.8 V DC Bluetooth IC supply SYRENTP110 2.8 V DC Internal analogue suppliesTP111 2.8 V DC RAM supplyCALYPSO+ wakes up13 MHz clock initialises R207 13 MHz sine Suspect CALYPSO+ and VCXO.