3-6
TROUBLESHOOTING TABLES
4.0
Troubleshooting Table for Board and IC Signals
IC Designator
Pin
Pin Function
DC Voltage
Comments (Condition)
U51
IFIC
1
RF input 44.85 MHz
1.20
2
RF input decoupling
1.20
3
2nd LO osc output
4.02
4
2nd LO osc input
4.60
5
RSSI output
0.74
(no received signal)
6
Vcc
4.70
7
Audio feedback
0.89
8
Audio output
1.44
DEMOD to stage U510
9
RSSI feedback
0.74
(no received signal)
10
Quad detector input
2.22
11
Limiter output
1.25
12
Limiter decoupling 2
1.30
13
Limiter decoupling 1
1.30
14
Limiter input
1.28
15
Ground
GND
16
IF amp output
1.22
17
IF amp decoupling 2
1.26
18
IF amp input
1.26
19
IF amp decoupling 1
1.26
20
2nd mixer output
3.09
U52
BW Select Switch
1
Inverter 1 input
0
(25 kHz mode)
2
Inverter 2 output
0
(25 kHz mode)
3
Inverter 3 input (NU)
GND
4
Ground
GND
5
Inverter 3 output (NU)
4.96
6
Inverter 2 input
3.00
(25 kHz mode)
7
Inverter 1 output
4.95
(25 kHz mode)
8
Vcc
4.96
Summary of Contents for CP 140
Page 1: ...Commercial Series CP140 CP160 CP180 Portable Radios Detailed Service Manual 6866550D20 O ...
Page 2: ...ii ...
Page 4: ...iv ...
Page 12: ...viii ...
Page 28: ...iv ...
Page 40: ...1 12 THEORY OF OPERATION ...
Page 48: ...2 8 TROUBLESHOOTING TABLES ...
Page 50: ...3 2 CONTROLLER KEYPAD SCHEMATICS ...
Page 58: ...3 10 Keypad Board Parts List 8466565A01 O ...
Page 62: ...iv ...
Page 66: ...1 4 MODEL CHART AND TECHNICAL SPECIFICATIONS ...
Page 90: ...3 16 TROUBLESHOOTING TABLES ...
Page 92: ...4 2 VHF PCB SCHEMATICS PARTS LISTS ...
Page 108: ...iv ...
Page 112: ...1 4 MODEL CHART AND TECHNICAL SPECIFICATIONS ...
Page 136: ...3 16 TROUBLESHOOTING TABLES ...
Page 138: ...4 2 UHF1 PCB SCHEMATICS PARTS LISTS ...
Page 154: ...iv ...
Page 158: ...1 4 MODEL CHART AND TECHNICAL SPECIFICATIONS ...
Page 182: ...3 16 TROUBLESHOOTING TABLES ...
Page 184: ...4 2 UHF2 PCB SCHEMATICS PARTS LISTS ...
Page 200: ...iv ...
Page 204: ...1 4 MODEL CHART AND TECHNICAL SPECIFICATIONS ...
Page 228: ...3 16 TROUBLESHOOTING TABLES ...