Fault Finding - Panasonic EB-X700 Service Manual

8 FAULT FINDING

8.1. RF Waveforms
NOTE: The measurements shown below are by FET probe. When using a FET probe, it should be protected by a
10 dB pad. Some of the measurement points are non-50
probe the output of the Power Amplifier or the Front-end Module's transmit path
2.7V
-50.4dBm
E-GSM-Rx
DCS-Rx
PCS-Rx
Front-end Module control logic, receive mode. High = 2.7V; Low = 0V
2.7V
Figure 8.2: Transceiver IC (U500) and Rx band-pass filters (FL502, FL503, and FL504),receive-path signals
PMCE041201C8
Service Manual
ASM
-50.4dBm
-50.5dBm
VC2
VC1
Figure 8.1: Front-end Module (U502), receive-path signals
PATH VC1
Low
Low
Low
TRX
2.7V
2.7V
Ω , therefore signal levels are approximate. Do not
VC3
VC2 VC3
High Low
Low Low
Low High
2.7V
Section 8
– 1 –
FAULT FINDING
-50dBm
Vdd
High
High
High
-
-49.4dBm
51.4dBm
-51.5dBm
-49.5dBm
-49.4dBm
-51.4dBm
Provisional Issue
Revision 1