TM8100/TM8200 Service Manual
Frequency Synthesizer Fault Finding
183
© Tait Electronics Limited
June 2006
7.
If the lock status is
110
, the second LO is out of lock. Go to
“Receiver Fault Finding” on page 239
8.
If the lock status is
111
, this implies normal operation. But if the lock
error persists, replace the board and go to
.
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 — two are supplied from the
PSU (power supply unit) module and two are produced in the synthesizer
circuitry itself:
■
: 14 V DC supply from SMPS (
VCL
SUPPLY
)
■
: 6 V DC supply from 6 V regulator in PSU module (
+6
V
0
)
■
: 5 V DC supply following filtering of 6 V supply (
+5
V
DEC
)
■
: 3 V DC supply from 3 V regulator in PSU module (
+3
V
0
AN
).
The measurement points for diagnosing faults in the power supplies are
summarized in
.
Figure 9.1
Measurement points for the frequency synthesizer power supply circuitry
PIN 4 OF
Q508
PIN 4 OF
Q508
PIN 4 OF
IC606
PIN 4 OF
IC606
PIN 5 OF
IC606
PIN 5 OF
IC606
Q500 AND
R533
Q500 AND
R533
PINS 7 AND 15
OF IC503
PINS 7 AND 15
OF IC503
SIGNAL TYPES
RF
ANALOG
CLOCK
DIGITAL
PLL
14 V
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
JUNCTION OF
C531 AND R530
+3V0 AN
L506
9 V
SUPPLY
6 V
SUPPLY
AGND
+9V0
+6V0
VCL SUPPLY
+5V DEC
Summary of Contents for TM8235
Page 1: ...TM8100 mobiles TM8200 mobiles Service Manual MMA 00005 04 Issue 4 June 2006...
Page 10: ...10 TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 62: ...62 Description TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 148: ...148 Disassembly and Reassembly TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 162: ...162 Servicing Procedures TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 178: ...178 Interface Fault Finding TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 258: ...258 Receiver Fault Finding TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 446: ...446 Spare Parts TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
