Power On Fault Analysis - Panasonic EB-X70 Service Manual

Signal
Serial Port
Supply Voltage
System Clock
Baseband Voltages
RTC 32 kHz clock
Battery Check
Battery Charging
ONNOFF

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.
Power-on sequence
VBAT is applied (> 2.6 V)
Release of Master Reset
Application of VRTC to 32 kHz
RTC
32 kHz clock runs
Power key is pressed
Power ON/OFF signal
CALYPSO+ and memory
regulator.
SYREN powers voltage
regulators
CALYPSO+ wakes up
13 MHz clock initialises
PMCD030901C8
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Details
Ensure all connections are
correctly.
Vbat should be 3.7 V.
Check that 13 MHz is present on
baseband.
Check the voltage levels of A28V,
D28VB, D28V, D18V, D20V, TP107-
TP111.
32 kHz clock signal applied
CALYPSO+. Check TP100.
Check resistance between T and minus
terminal of battery.
Incorrect or not charging.
The gate of FET Q100 (ICTL) should be
high.
Check D100, Q100.
TPEH18 should be high.
Expected
Test Point
Output
TP330/ 3.7 V
TP328
TPEJ15 Active low
TP112 1.5 V
TP100-1 32 kHz sine
TPA100 Active low
to TPEH18 2.2 V
high
TP107 1.5 V DC
TP108 2.8 V DC
TP109 2.8 V DC
TP110 2.8 V DC
TP111 2.8 V DC
R207 13 MHz sine
Section 8
– 49 –
Suspect Device
made Check using known 'good' phone.
Check power supply or that battery is
fully charged.
Check VCXO.
If levels are absent, suspect SYREN.
to If levels are absent, suspect SYREN.
Resistance should be approx. 10K.
Otherwise suspect SYREN.
If signal absent, suspect SYREN.
Battery connector and associated circuits.
If not present, suspect SYREN.
If not present, suspect CALYPSO+.
If not present, suspect crystal and CALYPSO+
If not present, suspect keyswitch.
active If not present, suspect keyswitch.
CALYPSO+ internal supply
Accessory supply
Bluetooth IC supply
Internal analogue supplies
RAM supply
Suspect CALYPSO+ and VCXO.
FAULT FINDING
Fault
Code
I
J
L
M
N
On failure
Suspect
SYREN
Issue 1
Revision 0