Tait TP9100, Руководство по обслуживанию, Страница: 163 / 326

TP9100 Service Manual
Frequency Synthesizer Fault Finding 163
© Tait Electronics Limited May 2005
9.2 Power Supplies
Introduction
First check that a power supply is not the cause of the fault. There are four
power supplies for the frequency synthesizer:
■
Task 3: 14V DC supply from SMPS (
VCL SUPPLY
)
■
Task 4: 5 V DC supply from 7
V
5
LINK
in power supply circuitry ( +5
V
0
AN
)
■
Task 5: 4.3 V DC supply following filtering of
5V
AN
(
+4
V
3
DEC
)
■
Task 6: 3V DC supply from 3V regulator in power supply circuitry
(
+3
V
0
AN
)
The measurement points for diagnosing faults in the power supplies are
summarized in
Figure 9.1 .
Figure 9.1 Measurement points for the synthesizer power supply circuitry
PIN 4 OF
IC601
PIN 4 OF
IC601
R533
PINS 7 AND 15
OF IC503
PINS 7 AND 15
OF IC503
SIGNAL TYPES
RF
ANALOG
CLOCK
DIGITAL
PLL
SMPS
LOOP
FILTER
AND
SUMMER
FILTERING
OF SUPPLY
FOR PLL
AND LOOP
FILTER
FILTERING
OF SUPPLY
FOR VCO
CIRCUITRY
3 V
SUPPLY
VCO
CIRCUITRY
FREQUENCY
SYNTHESIZER
INTERFACE
CIRCUITRY
INVERTER
JUNCTION OF
C531 AND R530
D512
JUNCTION OF
C531 AND R530
D512
+3V0 AN
L506
7V5
SUPPLY
5V
SUPPLY
AGND
+7V5 LINK
+5V0 AN
VCL SUPPLY +4V3 DEC
PIN 1 OF
Q508
PIN 1 OF
Q508
B1
PIN 4 OF
Q508
PIN 4 OF
Q508
H5/H6
Q500