Tait TM8100 mobiles, Service Manual

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TM8100/TM8200 Service Manual Transmitter Fault Finding (>25W) 271
© Tait Electronics Limited November 2007
11.1 Power Supplies
Introduction
First check that a power supply is not the cause of the fault. There are two
power supplies and a switch circuit for the transmitter:
■
Task 1 : 13.8V DC supply from power connector ( +13
V
8
BATT
)
■
Task 2 : switch circuit for 13.8V DC supply
■
Task 3 : 9V DC supply from 9V regulator in PSU module ( +9
V
0
TX
).
The measurement and test points for diagnosing faults in the power supplies
are summarized in
Figure 11.1 .
Figure 11.1 Measurement and test points for diagnosing faults involving the power supplies for
the transmitter
GND
TEST POINT
GND
TEST POINT
9V0 TX
TEST POINT
9V0 TX
TEST POINT
SIGNAL TYPES
RF
ANALOG
EXCITER PAs
FRE-
QUENCY
SYNTHE-
SIZER
OTHER
TRANS-
MITTER
CIRCUITRY
TRANSMITTER
INTERFACE
CIRCUITRY
DRIVER
+13.8 V DC SUPPLY
TO PA DRIVER
+13.8 V DC SUPPLY
TO PA DRIVER
+13.8 V DC
SUPPLY TO PAs
+13.8 V DC
SUPPLY TO PAs
L310
POWER
SUPPLY
AGND
+9V0 TX
+13V8 BATT
SWITCH
L306
VHF/UHF only