354
Transmitter Fault Finding (25W Radios)
TM9100 Service Manual
© Tait Electronics Limited
August 2005
12.4
RF Signal Path
Introduction
The RF signal path extends from the output of the frequency synthesizer to
the LPF. This section of circuitry will require investigation either following
certain checks in
“Transmitter RF Power”
or if the biasing checks of
“Biasing of PA Driver and PAs”
reveal no fault. The procedure is divided
into nine tasks grouped as follows:
■
Task 25
to
Task 28
: initial RF signal path
■
Task 29
and
Task 30
: directional coupler
■
Task 31
and
Task 32
: PIN switch
■
Task 33
: LPF
The initial signal path includes the exciter and PA driver. The directional
coupler, PIN switch, and LPF make up the final signal path.
The measurement points for diagnosing faults in the signal path are
summarized in
Figure 12.14
.
Figure 12.14 Measurement points for diagnosing faults in the RF signal path
TEST
CAPACITOR
TEST
CAPACITOR
L314
RF CON-
NECTOR
RECEIVER
LPF
DIREC-
TIONAL
COUPLER
PAs
PIN
SWITCH
DRIVER
EXCITER
FRE-
QUENCY
SYNTHE-
SIZER
SIGNAL TYPES
RF
ANALOG
SYNTHESIZER
OUTPUT
SYN TX LO
PA DRIVER
OUTPUT AT
DRAIN OF Q306
BUFFER
OUTPUT
AT C313
50
TEST
LEAD TO
TEST SET
Ω
50
TEST
LEAD TO
TEST SET
Ω
EXCITER
OUTPUT
GATES OF
Q309, Q310
C301
C300
Summary of Contents for TM9100
Page 1: ...TM9100 mobiles Service Manual MMA 00017 01 Issue 1 August 2005 ...
Page 4: ...4 TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 10: ...10 TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 22: ...22 Introduction TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 62: ...62 Description TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 96: ...96 TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 138: ...138 Disassembly and Reassembly TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 152: ...152 Servicing Procedures TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 168: ...168 Interface Fault Finding TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 244: ...244 Receiver Fault Finding TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 396: ...396 CODEC and Audio Fault Finding TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 420: ...420 Fault Finding of Control Head TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 426: ...426 Spare Parts TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 430: ...430 TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 444: ...444 TMAA04 05 Ignition Sense Kit TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 448: ...448 TMAA10 01 Desktop Microphone TM9100 Service Manual Tait Electronics Limited August 2005 ...