Tait TB7100, Service Manual

Page: 179 / 370

TB7100 Service Manual Frequency Synthesizer Fault Finding 181
© Tait Electronics Limited October 2005
Figure 11.11 Measurement points for the VCO and related circuitry in VHF radios
+5V
DEC
P
IN1O
F
D5004
PIN
1
OF
D5004
P
IN3O
F
Q5003
PIN
3
OF
Q5003
P
IN2O
F
Q5001
PIN
2
OF
Q5001
P
IN2O
F
D5004
PIN
2
OF
D5004
TX
POR
T
TX
POR
T
RX
POR
T
RX
POR
T
SIGNA
L
TYPES
RF ANALOG CLOCK DIGIT
AL
PLL
LOOP
FIL
TER
AND
SUMMER
FIL
TERING
OF
SUPPL
Y
FOR
VCO
CIRCUITR
Y
FREQUENCY
SYNTHESIZER
PLL
FEEDBACK
VCO
BUFFER
AMPLIFIER
AND
COUPLER
D5004
5
V
SWITCH
TR
SWITCH
SYN
TX
LO
SYN
RX
LO1
TRANS- MITTER
RECEIVER
DIGIT
AL
BOARD
DIG
SYN
TR
SW
DIG
SYN
EN
INVER
TER
VIA
T
O
CHECK
DIG
SYN
TR
SW
VIA
T
O
CHECK
DIG
SYN
TR
SW
R103
R544
JUNCTION
OF
C541
AND
R547
JUNCTION
OF
C541
AND
R547
+3V0
AN
L506
3V
SUPPL
Y