FAULT FINDING
PMCD030901C8 Section 8 Issue 1
Service Manual – 49 – Revision 0
8.3. Power on fault analysis
The handset uses underfill techniques on some components which renders them unserviceable. These components include
CALYPSO+ and SYREN. If these components are found to be faulty a replacement PCB will be required to repair the
handset.
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 sequence
as detailed below.
Signal Details Suspect Device
Fault
Code
Serial Port Ensure all connections are made
correctly.
Check using known ‘good’ phone.
Supply Voltage Vbat should be 3.7 V. Check power supply or that battery is
fully charged.
System Clock Check that 13 MHz is present on
baseband.
Check VCXO. I
Baseband Voltages Check the voltage levels of A28V,
D28VB, D28V, D18V, D20V, TP107-
TP111.
If levels are absent, suspect SYREN. J
RTC 32 kHz clock 32 kHz clock signal applied to
CALYPSO+. Check TP100.
If levels are absent, suspect SYREN. L
Battery Check Check resistance between T and minus
terminal of battery.
Resistance should be approx. 10K.
Battery Charging Incorrect or not charging.
The gate of FET Q100 (ICTL) should be
high.
Check D100, Q100.
Otherwise suspect SYREN. M
ONNOFF TPEH18 should be high. If signal absent, suspect SYREN. N
Power-on sequence Test Point
Expected
Output
On failure
VBAT is applied (> 2.6 V) TP330/
TP328
3.7 V Battery connector and associated circuits.
Release of Master Reset TPEJ15 Active low If not present, suspect SYREN.
Application of VRTC to 32 kHz
RTC
TP112 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 to
CALYPSO+ and memory
regulator.
TPEH18 2.2 V active
high
If not present, suspect keyswitch.
SYREN powers voltage TP107 1.5 V DC CALYPSO+ internal supply
regulators TP108 2.8 V DC Accessory supply Suspect
TP109 2.8 V DC Bluetooth IC supply SYREN
TP110 2.8 V DC Internal analogue supplies
TP111 2.8 V DC RAM supply
CALYPSO+ wakes up
13 MHz clock initialises R207 13 MHz sine Suspect CALYPSO+ and VCXO.
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