Power Supplies - Introduction - Tait TM9100 Service Manual

12.1 Power Supplies
First check that a power supply is not the cause of the fault. There are two
Introduction
power supplies and a switch circuit for the transmitter:
The measurement and test points for diagnosing faults in the power supplies
are summarized in
Figure 12.1 Measurement and test points for diagnosing faults involving the power supplies for
the transmitter
TRANSMITTER
+13.8 V DC +13.8 V DC
SUPPLY TO PAs SUPPLY TO PAs
SIGNAL TYPES
RF
ANALOG
OTHER
TRANS-
MITTER
CIRCUITRY
318 Transmitter Fault Finding (25W Radios)
Task 1: 13.8V DC supply from power connector (+13
Task 2: switch circuit for 13.8V DC supply
Task 3: 9V DC supply from 9V regulator in PSU module (+9
Figure
+13.8 V DC SUPPLY +13.8 V DC SUPPLY
TO PA DRIVER TO PA DRIVER
L310 L306
PAs DRIVER
12.1.
9V0 TX 9V0 TX
TEST POINT TEST POINT
SWITCH
GND GND
TEST POINT TEST POINT
EXCITER
© Tait Electronics Limited August 2005
8
)
V BATT
0
)
V TX
+9V0 TX
POWER
SUPPLY
+13V8 BATT
AGND
INTERFACE
CIRCUITRY
FRE-
QUENCY
SYNTHE-
SIZER
TM9100 Service Manual