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Tait TB8100 Service Manual
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130
Power Amplifier Fault Finding
TB8100 Service Manual
© Tait Electro
nics Limited September 2006
Figure 8.1
Identifying the circuit boards in a 28
V P
A
b
6
W board
g
5
W interconnect board
c
60
W board
h
50
W interconnect bo
ard
d
low pass filter/directional coupler board
i
splitter board
e
control board
j
combiner board
f
ambient air temperatur
e sensor boar
d
1)
100
W i
nterc
onnect board (VHF only)
5W
P
A
50
W P
A
100
W P
A
(VHF)
f
f
f
b
g
e
under
shield
d
e
under
shield
d
b
h
c
b
e
c
c
d
j
i
1)
129
131
Table of Contents
Default Chapter
2
Issue
2
Table of Contents
3
Tait Electronics Limited September
8
Preface
12
Scope of Manual
12
Document Conventions
12
Associated Documentation
13
Publication Record
14
1 Safety and Servicing Information
15
Personal Safety
15
Lethal Voltages
15
Explosive Environments
16
Beryllium Oxide
16
Proximity to RF Transmissions
16
High Temperatures
16
Equipment Safety
17
ESD Precautions
17
Antenna Load
17
Figure 1.1 Typical Antistatic Bench Set-Up
17
Regulatory Information
18
Distress Frequencies
18
FCC Compliance
18
Unauthorised Modifications
18
General Servicing Information
19
Repair Levels
19
Accreditation of Service Centres
19
Skills and Resources for Level-1 Repairs
19
Skills and Resources for Level-2 Repairs
19
Website Access
20
Items Available on Website
20
PCB Information
21
Tait FOCUS Database
21
Recommended Tools
22
Identifying Screw Types
23
Torx Recess Head Screws
23
Allen Recess Head UNC Screws
23
Pozidriv Recess Head Screws
23
Figure 1.2 Identifying Torx Screws
23
Figure 1.3 Identifying Pozidriv and Phillips Screws and Screwdrivers
24
Replacing Components
25
Surface Mount Devices
25
Leaded Components
25
Cased Mica Capacitors
26
2 Reciter Circuit Description
27
Figure 2.1 Reciter High Level Block Diagram
28
Digital Circuitry
29
Digital if
29
Digital Signal Processor (DSP)
30
Figure 2.2 Reciter Digital Circuitry Block Diagram
31
Reduced Instruction Set Computer (RISC)
32
Figure 2.3 Reciter RISC Functional Block Diagram
33
40Mhz Digital Clock
35
Reference Switch
35
Synthesizer
35
Vcxo
36
Reference Switch
36
Figure 2.4 Reciter External Reference Block Diagram
37
Receiver RF Circuitry - VHF Reciter
38
Front End
38
Mixer
38
IF Circuitry
38
Figure 2.5 Reciter VHF Receiver RF Circuitry Block Diagram
38
Synthesizer
39
Vco
40
Figure 2.6 Reciter Receiver Synthesizer Block Diagram
41
Receiver RF Circuitry - UHF Reciter
42
Front End
42
Figure 2.7 Reciter UHF Receiver RF Circuitry Block Diagram
42
Mixer
43
IF Circuitry
43
Synthesizer
43
Vco
44
Figure 2.8 Reciter Receiver Synthesizer Block Diagram
45
AGC (H Band Only)
46
Exciter RF Circuitry
47
Frequency Control Loop
47
Synthesizer
48
Figure 2.9 Comparison of VCXO and VCO Modulation Responses
48
Figure 2.10 Reciter Exciter Synthesizer Modulator Block Diagram - B, C and H Bands
49
Figure 2.11 Reciter Exciter Synthesizer Modulator Block Diagram - K and L Bands
50
VCO - VHF Reciter
51
VCO - UHF Reciter
52
Exciter Control Circuit
53
System Interface Boards
54
Figure 2.12 Reciter System Interface Board Block Diagram
56
Power Supply
59
Figure 2.13 Reciter Power Supply Block Diagram
60
Figure 2.14 Identifying the Circuitry on the Digital and System Interface Boards
61
Figure 2.15 Identifying the Circuitry on the RF Board - B and C Bands
63
Figure 2.16 Identifying the Circuitry on the RF Board - H Band
65
Figure 2.17 Identifying the Circuitry on the RF Board - K and L Bands
67
3 Reciter Fault Finding
69
Identifying the Reciter
70
Figure 3.1 Identifying the Reciter Boards
71
Test Equipment
72
Figure 3.2 Recommended Test Equipment Set-Up
73
Software and Firmware Compatibility
74
Board Replacement
75
Initial Checks
76
Figure 3.3 Typical 12.8Mhz Clock Wave Form
80
Figure 3.4 Location of the 12.8Mhz Clock Test Point on the RF Board
81
Visual Inspection
82
Figure 3.5 Visual Inspection Points for the Reciter
83
Digital if
84
Receiver
85
Exciter
86
Audio
89
Figure 3.6 Recommended Test Equipment Set-Up for Audio Checks
90
Figure 3.7 Location of Audio Test Points on the Digital Board
91
Figure 3.8 Location of Audio Test Points on the System Interface Board
94
Final Tasks
95
4 Reciter Disassembly and Reassembly
99
Screw Torque Settings
100
Removing the Covers
100
Removing the Front and Rear Panels
100
Tait Electronics Limited September
101
Refitting the Front and Rear Panels
102
Refitting the Covers
102
5 Reciter Board Replacement
103
Replacing the System Interface Board
104
Figure 5.1 Replacing the System Interface Board
106
Figure 5.2 Reconnecting the Flexible Connector
107
6 Reciter Spare Parts
109
Figure 6.1 Reciter Mechanical Assembly
111
7 Power Amplifier Circuit Description
113
Figure 7.1 PA High Level Block Diagrams
114
Microprocessor Control Circuitry
115
Diagnostics and Alarms
115
PA-Key
116
Power Foldback
116
Figure 7.2 PA Control, RF and Power Supply Circuitry Block Diagram
117
Shutdown
118
Power Control
118
Fan Control
119
Power Supplies
119
Temperature Monitoring
119
Ambient Air Temperature Sensor
120
RF Circuitry
120
6W Board
120
Low Pass Filter and Directional Coupler Board
121
Splitter and Combiner Boards
121
Interconnect Boards
121
Boost Regulator Circuitry (12V PA Only)
122
Figure 7.3 Identifying the Circuitry on the 28V PA Boards
123
Figure 7.4 Identifying the Circuitry on the 12V PA Boards
125
8 Power Amplifier Fault Finding
127
Safety Precautions
128
Personal Safety
128
Equipment Safety
128
Identifying the PA
129
Figure 8.1 Identifying the Circuit Boards in a 28V PA
130
Figure 8.2 Identifying the Circuit Boards in a 12V PA
131
Test Equipment
132
Figure 8.3 Recommended Test Equipment Set-Up for Initial Checks - 28V PA
134
Figure 8.4 Recommended Test Equipment Set-Up for Initial Checks - 12V PA
135
Software and Firmware Compatibility
136
Board Replacement
137
Initial Checks
138
Figure 8.5 Connections on the Fan Contact Board
140
Visual Inspection
144
Figure 8.6 Visual Inspection Points for a 28V PA
146
Figure 8.7 Additional Visual Inspection Points for a 12V PA
147
Control Board
148
Figure 8.8 Recommended Test Equipment Set-Up for Circuit Board Checks - 28V PA
149
Figure 8.9 Recommended Test Equipment Set-Up for Circuit Board Checks - 12V PA
150
Figure 8.10 Location of Test Points on the Control Board
153
Board
155
Figure 8.11 Location of Test Points on the 6W Board
155
Splitter and Combiner Boards (100W PA Only)
160
Figure 8.12 Location of Test Points on the Splitter and Combiner Boards
160
Board
162
Figure 8.13 Location of Test Points on the 60W Board
162
Low Pass Filter and Directional Coupler Board
165
Figure 8.14 Location of the Test Points and Input Coupling Components on the Lpf/Directional Coupler Board
166
Boost Regulator Board (12V PA Only)
168
Figure 8.15 Test Equipment Set-Up for the Boost Regulator Board
169
Figure 8.16 Location of Test Points on the Boost Regulator Board
169
Final Tasks
170
9 Power Amplifier Disassembly and Reassembly
173
Screw Torque Settings
174
Removing the Airflow Duct and Cover
174
Figure 9.1 Removing the Airflow Duct and Cover
175
Removing the Front Panel
176
Figure 9.2 Removing the Front Panel
176
Refitting the Front Panel
177
Refitting the Cover and Airflow Duct
177
10 Power Amplifier Board Replacement
179
Circuit Board Connecting Links
180
Replacing the 6W Board
180
Figure 10.1 Circuit Board Connecting Links
180
Figure 10.2 Replacing the 6W Board
181
Replacing the 60W Board
182
Figure 10.3 Replacing the 60W Board
183
Replacing the 60W RF Power Transistor
184
Figure 10.4 Replacing the 60W RF Power Transistor
185
Replacing the Control Board
186
Figure 10.5 Replacing the Control Board
187
Replacing the Low Pass Filter/Directional Coupler Board
188
Figure 10.6 Replacing the Lpf/Directional Coupler Board
189
Replacing the Splitter/Combiner Boards
190
Figure 10.7 Replacing the Splitter/Combiner Boards
191
Replacing the Interconnect Boards
192
Replacing the Boost Regulator Board in a 12V PA
193
Figure 10.8 Replacing the Boost Regulator Board in a 12V PA
194
11 Power Amplifier Spare Parts
195
Figure 11.1 PA Mechanical Assembly - 28V Pas
197
Figure 11.2 PA Mechanical Assembly - 12V Pas
198
Figure 11.3 PA Mechanical Assembly - Covers and Airflow Duct
199
12 Power Management Unit Circuit Description
201
Figure 12.1 PMU High Level Block Diagram
202
Microprocessor Control Circuitry
203
Figure 12.2 PMU Microprocessor Functional Block Diagram
204
AC Module
206
Figure 12.3 PMU AC Module Block Diagram
206
DC Module
208
Figure 12.4 PMU DC Module Block Diagram
208
Figure 12.5 Identifying the Circuitry in the AC Module
211
Figure 12.6 Identifying the Circuitry in the DC Module
213
13 Power Management Unit Fault Finding
215
Safety Precautions
216
Personal Safety
216
Equipment Safety
216
Identifying the PMU
217
Colour Coding of Circuit Boards and Cards
217
Figure 13.1 Identifying the Boards and Cards in the PMU
218
Test Equipment
219
Software and Firmware Compatibility
220
Board Replacement
221
Initial Checks
222
Figure 13.2 Recommended Test Equipment Set-Up for Initial and DC Checks
222
Figure 13.3 Location of Indicator Leds and DC Output Connectors
223
Figure 13.4 Connections on the Fan Contact Board
227
Auxiliary Power Supply Board
229
DC Module
230
DC Converter Without Microprocessor Control
230
Figure 13.5 Checking the DC Converter Without Microprocessor Control
231
Figure 13.6 Location of Test Point on the Battery Control Card
232
Figure 13.7 Location of Test Points on the DC Control Card
233
DC Converter with Microprocessor Control
234
Figure 13.8 Checking the DC Converter with Microprocessor Control
235
Tait Electronics Limited September
235
PMU Operation on DC Input
237
Figure 13.9 PMU Alarm Thresholds and Voltage Limits When Operating on DC
238
AC Module
240
Figure 13.10 Location of Test Points on the AC Converter Board
241
Figure 13.11 AC Converter Test Equipment Set-Up
243
Figure 13.12 Typical Gate-Source and Drain-Source Waveforms for Fets
244
13.10 Modifying the PFC Control Card
246
Figure 13.13 Modifying the PFC Control Card for Testing the AC Converter
246
13.11 Final Tasks
247
14 Power Management Unit Disassembly and Reassembly
249
Safety Precautions
249
Personal Safety
249
Equipment Safety
250
Mechanical Overview
251
Screw Torque Settings
252
Removing the Top and Bottom Covers
252
Removing the Front and Rear Panels
253
Figure 14.1 Removing the Front and Rear Panels
253
Disconnecting the AC and DC Modules
254
Reconnecting the AC and DC Modules
254
Figure 14.2 Disconnecting the AC and DC Modules
255
Figure 14.3 Reconnecting the AC and DC Modules
256
Refitting the Front and Rear Panels
257
Refitting the Top and Bottom Covers
258
15 Power Management Unit Card and Board Replacement
259
Safety Precautions
259
Personal Safety
259
Equipment Safety
260
Colour Coding of Circuit Boards and Cards
260
Replacing the Plug-In Cards
261
Figure 15.1 Replacing the Plug-In Cards
263
Replacing the Auxiliary Power Supply Board
265
Figure 15.2 Replacing the Auxiliary Power Supply Board
265
16 Power Management Unit Spare Parts
267
Figure 16.2 PMU Mechanical Assembly - Sheet 2
270
17 Control Panel Circuit Description
271
Control Circuitry
272
Audio Circuitry
272
Power Save
273
Power Supply
273
Figure 17.1 Standard, Dual Base Station, and Power Save Control Panel High Level
274
Figure 17.2 Multi-Reciter Control Panel High Level Block Diagram
275
18 Control Panel Servicing
277
Identifying the Control Panel
278
Screw Torque Settings
278
Replacing the Circuit Board
279
Figure 18.1 Replacing the Control Panel Board
280
Figure 18.2 Reconnecting the Flexible Connector
281
Replacing the Speaker
282
Figure 18.3 Replacing the Speaker
283
Spare Parts
284
Figure 18.4 Control Panel Mechanical Assembly - Standard, Power Save, and
285
Figure 18.5 Control Panel Mechanical Assembly - Multi-Reciter
286
Figure 19.1 Front Panel Mechanical Assembly
289
Figure 19.2 Subrack Mechanical Assembly
290
Figure 19.3 Cable Identification - Sheet 1
291
Figure 19.4 Cable Identification - Sheet 2
292
Figure 19.5 Cables and Mechanical Parts Used in the Multi-Reciter Subrack
293
Important Notice
303
Limited Warranty
304
Other manuals for Tait TB8100
User Manual
254 pages
Installation Guide
32 pages
Installation And Operation Manual
144 pages
Technical Support
9 pages
Installation
20 pages
Using
10 pages
4
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Tait TB8100 Specifications
General
Brand
Tait
Model
TB8100
Category
Accessories
Language
English
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