Harris Intelligent Transmitter Platinum-i Series Technical Manual

TECHNICAL MANUAL

888-9058-001

Platinum-i Series Intelligent

Transmitter™

Platinum-i Series Intelligent Transmitter™

T.M. No. 888-9058-001

______________________________________________HARRIS

888-9058-001

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Returns And Exchanges

Damaged or undamaged equipment should not be returned unless written approval

and a Return Authorization is received from HARRIS Broadcast Communications

Division. Special shipping instructions and coding will be provided to assure proper

handling. Complete details regarding circumstances and reasons for return are to be

included in the request for return. Custom equipment or special order equipment is

not returnable. In those instances where return or exchange of equipment is at the

request of the customer, or convenience of the customer, a restocking fee will be

charged. All returns will be sent freight prepaid and properly insured by the

customer. When communicating with HARRIS Broadcast Communications

Division, specify the HARRIS Order Number or Invoice Number.

Unpacking

Carefully unpack the equipment and perform a visual inspection to determine that

no apparent damage was incurred during shipment. Retain the shipping materials

until it has been determined that all received equipment is not damaged. Locate and

retain all PACKING CHECK LISTS. Use the PACKING CHECK LIST to help

locate and identify any components or assemblies which are removed for shipping

and must be reinstalled. Also remove any shipping supports, straps, and packing

materials prior to initial turn on.

Technical Assistance

HARRIS Technical and Troubleshooting assistance is available from HARRIS

Field Service during normal business hours (8:00 AM - 5:00 PM Central Time).

Emergency service is available 24 hours a day. Telephone 217/222-8200 to contact

the Field Service Department or address correspondence to Field Service

Department, HARRIS Broadcast Communications Division, P.O. Box 4290,

Quincy, Illinois 62305-4290, USA. Technical Support by e-mail:

[email protected]m. The HARRIS factory may also be contacted through a FAX

facility (217/221-7096).

Replaceable Parts Service

Replacement parts are available 24 hours a day, seven days a week from the

HARRIS Service Parts Department. Telephone 217/222-8200 to contact the service

parts department or address correspondence to Service Parts Department, HARRIS

CORPORATION, Broadcast Systems Division, P.O. Box 4290, Quincy, Illinois

62305-4290, USA. The HARRIS factory may also be contacted through a FAX

facility (217/221-7096).

NOTE:

The # symbol used in the parts list means used with (e.g. #C001 = used with C001).

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Manual Revision History

Platinum-i Series Intelligent Transmitter™ Technical Manual

Rev Date ECN Description

A 22Apr2010 P43417 Released

B 20May2010 P47546 Revised Title Page, MRH, and Step-2 on Page-90

Guide to Using Harris Parts List Information

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The Harris Replaceable Parts List Index portrays a tree structure with the major items being leftmost in the index. The

example below shows the Transmitter as the highest item in the tree structure. If you were to look at the bill of materials table

for the Transmitter you would find the Control Cabinet, the PA Cabinet, and the Output Cabinet. In the Replaceable Parts

List Index the Control Cabinet, PA Cabinet, and Output Cabinet show up one indentation level below the Transmitter and

implies that they are used in the Transmitter. The Controller Board is indented one level below the Control Cabinet so it will

show up in the bill of material for the Control Cabinet. The tree structure of this same index is shown to the right of the table

and shows indentation level versus tree structure level.

Example of Replaceable Parts List Index and equivalent tree structure:

Replaceable Parts List Index Part Number Page

Table 7-1. Transmitter 994 9283 001 7-2

Table 7-2. Control Cabinet 992 9244 002 7-3

Table 7-3. Controller Board 992 8344 002 7-6

Table 7-4. PA Cabinet 992 9400 002 7-7

Table 7-5. PA Amplifier 994 7894 002 7-9

Table 7-6. PA Amplifier Board 992 7904 002 7-10

Table 7-7. Output Cabinet 992 9450 001 7-12

The part number of the item is shown to the right of the description as is the page in the manual where the bill for that

part number starts. Inside the actual tables, four main headings are used:

• Table #-#. ITEM NAME - HARRIS PART NUMBER - this line gives the information that corresponds

to the

Replaceable Parts List Index entry;

• HARRIS P/N column gives the ten DIGIT Harris part number (usually in ascending order);

• DESCRIPTION column gives a 25 character or less description of the part number;

• REF. SYMBOLS/EXPLANATIONS column 1) gives the reference designators for the item (i.e., C001,

R102,etc.) that corresponds to the number found in the schematics (C001 in a bill of material is equivalent

to C1 on the schematic) or 2) gives added information or further explanation (i.e., “Used for 208V

operation only,” or “Used for HT 10LS only,” etc.).

Inside the individual tables some standard conventions are used:

• A # symbol in front of a component such as #C001 under the REF. SYMBOLS/EXPLANATIONS

column means that this item is used on or with C001 and is not the actual part number for C001.

• In the ten digit part numbers, if the last three numbers are 000, the item is a part that Harris has

purchased and has not manufactured or modified. If the last three numbers are other than 000, the item is

either manufactured by Harris or is purchased from a vendor and modified for use in the Harris product.

• The first three digits of the ten DIGIT part number tell which family the part number belongs to - for

example, all electrolytic (can) capacitors will be in the same family (524 xxxx 000). If an electrolytic (can)

capacitor is found to have a 9xx xxxx xxx part number (a number outside of the normal family of

numbers), it has probably been modified in some manner at the Harris factory and will therefore show up

farther down into the individual parts

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list (because each table is normally sorted in ascending order). Most Harris made or modified assemblies

will have 9xx xxxx xxx numbers associated with them.

The term “SEE HIGHER LEVEL BILL” in the description column implies that the reference designated

part number will show up in a bill that is higher in the tree structure. This is often the case for components

that may be frequency determinant or voltage determinant and are called out in a higher level bill structure

that is more customer dependent than the bill at a lower level.

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WARNING:

THE CURRENTS AND VOLTAGES IN THIS EQUIPMENT ARE DANGEROUS.

PERSONNEL MUST AT ALL TIMES OBSERVE SAFETY WARNINGS, INSTRUCTIONS

AND REGULATIONS.

This manual is intended as a general guide for trained and qualified personnel who are

aware of the dangers inherent in handling potentially hazardous electrical/electronic

circuits. It is not intended to contain a complete statement of all safety precautions which

should be observed by personnel in using this or other electronic equipment.

The installation, operation, maintenance and service of this equipment involves risks both

to personnel and equipment, and must be performed only by qualified personnel

exercising due care.

HARRIS CORPORATION shall not be responsible for injury or damage resulting from

improper procedures or from the use of improperly trained or inexperienced personnel

performing such tasks. During installation and operation of this equipment, local building

codes and fire protection standards must be observed.

The following National Fire Protection Association (NFPA) standards are recommended

as reference:

- Automatic Fire Detectors, No. 72E

- Installation, Maintenance, and Use of Portable Fire Extinguishers, No. 10

- Halogenated Fire Extinguishing Agent Systems, No. 12A

WARNING:

ALWAYS DISCONNECT POWER BEFORE OPENING COVERS, DOORS,

ENCLOSURES, GATES, PANELS OR SHIELDS. ALWAYS USE GROUNDING STICKS

AND SHORT OUT HIGH VOLTAGE POINTS BEFORE SERVICING. NEVER MAKE

INTERNAL ADJUSTMENTS, PERFORM MAINTENANCE OR SERVICE WHEN ALONE

OR WHEN FATIGUED.

Do not remove, short-circuit or tamper with interlock switches on access covers, doors,

enclosures, gates, panels or shields. Keep away from live circuits, know your equipment

and don’t take chances.

WARNING:

IN CASE OF EMERGENCY ENSURE THAT POWER HAS BEEN DISCONNECTED.

WARNING:

IF OIL FILLED OR ELECTROLYTIC CAPACITORS ARE UTILIZED IN YOUR

EQUIPMENT, AND IF A LEAK OR BULGE IS APPARENT ON THE CAPACITOR CASE

WHEN THE UNIT IS OPENED FOR SERVICE OR MAINTENANCE, ALLOW THE UNIT

TO COOL DOWN BEFORE ATTEMPTING TO REMOVE THE DEFECTIVE

CAPACITOR. DO NOT ATTEMPT TO SERVICE A DEFECTIVE CAPACITOR WHILE IT

IS HOT DUE TO THE POSSIBILITY OF A CASE RUPTURE AND SUBSEQUENT

INJURY.

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Table of Contents

Platinum-i Series Analog

Transmitter

Section 1

Introduction

Introduction....................13

Transmitter Configurations......13

Organization of Transmitter Doc.14

GeneralDescription..............15

AC Power Distribution...........16

Transmitter Control System......17

Main Controller.................17

PA Cabinet Slave Controllers....17

Control Cabinet.................18

Control System Block Diagram....19

50 Volt Power Supply............20

RF Amplifier Modules............20

Power Amplifier Modules.........20

Driver Modules..................20

Visual Signal Flow Path.........20

Exciter.........................20

Transmitter AGC Module..........21

Phase and Gain Module...........21

Visual RF Chains................21

Aural Signal Path...............23

Exciter.........................23

Dual Carrier Systems............23

AGC Module......................23

Phase and Gain..................24

Aural RF Amplifier Chains.......24

Transmitter Output Networks.....25

Transmitter System Theory.......25

Control System..................25

Main Controller Board...........26

PA Cabinet Slave Controller ....26

Module Controller...............26

Control Cabinet.................26

Exciter Switcher................26

Transmitter AGC Module..........26

Phase and Gain..................26

Signal Interface................27

RF PA Cabinets..................27

50 Volt Power Supply............27

RF Output Systems...............27

Platinum RF Combining para......28

Percent of Cabinet Power 3 Cab..28

Percent of Cabinet Power 4 Cab..29

Specifications..................30

Section 2

Installation

Introduction....................33

Installation Planning...........33

Space Requirements..............35

Weights.........................35

RF System Layout................35

Air System......................36

Outside Air Cooling.............36

Air Conditioning................37

Electrical Power................37

Circuit Breaker Selection.......37

Isolation Transformer...........38

Unpacking and EquipmentInvent...38

Equipment Required for Unload...38

Inventory and Inspection........39

Packing Check List..............39

Factory Test Data Sheets........39

Cabinet Placement and Leveling..40

Grounding.......................40

Tap Transformers................41

Installation of 50 Volt Supp....41

RF Output Coax..................41

AC Primary Wiring...............42

UPS Installation................42

Inter-cabinet Wiring............42

Input Signal Wiring.............43

Interlocks and Interfaces.......43

External Interlock: TB1-1, 2....43

Fail-safe Interlock: TB1-3, 4...43

Individual PA Cab External Int..44

External Blower Control.........44

RF Samples......................44

Remote Control I/O..............45

Command In......................45

J31 COMMAND INPUTS..............45

Command Functions...............46

J32: Status Outputs.............46

Status Functions................47

J33: Analog Outputs.............48

J33 Calibrated Outputs Range....48

Optional Remote Status..........48

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Table of Contents (continued)

J34 Optional Status...............49

Transmitter Check Out.............49

Control Cabinet Pre-Operational...49

3 Phase AC and Logic SupplyCheck..49

GUI Setup.........................50

PA Cabinet Checkout...............51

Module Installation...............53

Control System Check Out..........53

Initial Applctn RF Visual Power...54

InitialApplctn RF Aural Power.....55

Power Calibration.................57

Basics of Power Calibration.......57

Visual Power Calibration..........57

PA Cabinet Power Calibration......58

Two Cabinet Reject Load...........58

Three and Four Cabinet Calibra....58

Aural Power Calibration...........59

System Forward Power..............59

Reflected Power...................59

PA Cabinet Power Calibration......59

Two Cabinet Reject Load...........59

Three and Four Cabinet Calibra....60

Visual VSWR Calibration...........60

Aural VSWR Calibration............61

Power Limit.......................62

Section 3

Software Installation/Setup

Re Introduction...................63

eCDi™ and the Platinum-i™Trans....63

Hardware..........................64

Features..........................64

Web GUI...........................65

SNMP Agent........................66

Level 1/Level 2 Functionality.....66

Security..........................67

Downloading the Manual............67

Setup.............................68

Detailed Installation Procedures..69

CD-1A Exciter Serial Number Reset.69

eCDi™ Configuration...............70

Troubleshooting Tips..............72

Apply Changes.....................86

Backing Up the Configuration......87

Restoring a Configuration File....87

Reset Computer IP Address.........87

eCDi Software Updates.............88

Updating the eCDi™.............88

Before Starting................88

Main Controller SerialProgram..91

Exciter Switcher...............92

AGC Module.....................93

PA Cabinets....................95

Slave Controller Indicators....95

RF PA Module LED Display.......97

Operation......................98

Turn ON Sequence...............98

Turn OFF Sequence..............98

Power Raise/Lower..............99

AGC Setup......................99

Section 4

Operation

Introduction..................101

Graphical User Interface......101

376 Micro Controller CPLD.....102

Front Control Panel...........103

CONTROL Pushbuttons...........103

STATUS Indicators/Pushbuttons.103

Auxiliary Control Panel.......104

GUI and eCDi Control..........105

A Short Tutorialusing the GUI.107

GUI Display Screen............109

Fault & Event Screen..........109

Fault Alarm Listing...........110

Control Section...............111

Status and Metering Screens...111

Drive Tab.....................111

PA Cabinet Tab................115

Output Tab....................118

P.S. Power Supply Tab.........122

System Tab....................125

GUI Screen Faults Sum List....127

Section 5

Control System Theory

ControlSystemOverall Descrip..129

Transmitter Control System....129

Micro Module..................131

Features of the 376 module....132

CPLD, Complex Prog Logic Dev..132

I/O Expansion.................132

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Table of Contents (continued)

Life Support Backup..............133

Controller Area Network(CAN)Bus..133

Main Controller..................135

Transmitter Control..............135

Graphical User Interface (GUI)...135

Remote Controls..................135

Control Panel & Indicator Dis....135

Introduction.....................137

Modes of Operation...............137

Button Press.....................137

Button / Indicator Lighting......138

Button States....................139

Messages in the LED Display......140

FP Error.........................140

Com Error, Main Controller.......140

Other Indicators.................140

LIfe Support Functionality.......141

Status Indicators................141

Switches.........................141

Test Points......................141

Module Logic.....................142

Main Controller..................142

Platinum-i TV Controller.........142

Micromodule Interface (Sheet 2)..143

Micro Module (Sheet 3)...........143

Development Hrdwr & Bd (Sheet 3).143

RS232, Watch Dog & Fr Pnl(Sht4)..144

Controller Analog Sense (Sht 5)..144

CPLD (Sheet 6)...................144

Cabinet Bus Controller (Sht 7)...145

Transmitter ON/OFF Cntrl (Sht 8).145

Foldback Voltage D /A (Sheet 9)..145

Controller/Exc Swtchr (Sht 10)...145

Line Voltage & AGC Mon(Sht 11)...145

Interlocks (Sheet 12)............146

Peak Detectors (Shts 13 and 14)..146

Fault Detection (Sheet 15).......146

Dual Tran Interface (Sheet 16)...147

Remote Commands Input (Sht 17)...147

Remote Status Out (Shts 18-19)...147

Optional Remote Status (Sht 20)..147

Remote Analog Outputs (Sheet 21).147

DC Distribution..................148

The Slave Controller Descrip.....148

Slave Controller...............148

Sheet 1........................148

Sheet 2........................149

Sheets 3 and 4.................149

Sheet 5........................149

Sheet 6........................150

Sheet 7........................150

Sheet 8........................150

Sheet 9........................150

Graphical User Interface.......150

Section 6

Control Cabinet

Introduction...................151

Control Cabinet Common.........151

Control Interconnects..........152

AC Power Distribution..........152

DC Power Supplies..............152

Diode Oring....................153

Wiring Diagram, Cntrl Cab Dig..153

RF Flow Path...................153

Main Controller................153

Front Panel Switch Unit........153

Display Unit...................154

Accessory Tray.................154

Exciter Switcher (843-5275-211)154

Logic Crd Detailed Ckt Descrip.155

Exciter Switcher Relay Bd Pnl..155

Operational Setup and Adj......155

Troubleshooting................157

AGC............................157

Detailed Circuit Description...157

Operational Setup and Adj......158

Troubleshooting................158

Phase and Gain.................159

Detailed Circuit Description...159

Operational Setup and Adj......161

Troubleshooting................162

UPS Battery Testing............162

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Table of Contents (continued)

Section 7

PA Cabinet

Introduction.....................163

Theory of Operation..............163

AC Power Flow....................163

Fan and air flow monitoring......163

Interlock Circuits...............163

SCR crowbar......................164

Mechanical Shorting Switch.......164

PA Cabinet Control Logic.........164

Analog PA Cabinet RF Config......164

15KW Vision only PA Cabinet......164

Vision Driver & Sound PA Cabinet.165

Comb Sound & Vision 10KW PA Cab..165

Power Divider....................165

PA Output Combiner Network.......166

Gysel Combiner Theory............166

Maintenance and Troubleshooting..168

Cooling System...................168

Air Filter Replacement...........168

Air Switch Adjustment............168

Back Door Fan....................170

Check for Loose Connections......170

Check MOV Boards.................171

Checking Multi PA Cab Intrlcks...171

Cleaning.........................171

RF Trouble Shooting Divider Comb.172

Section 8

RF Amplifier Modules

General Information..............173

Factory Module Repair............173

Local Module Repair..............174

Module Part Numbers..............174

RF Amplifier Modules Theory......175

Driver Module, Lo Band (Band I)..176

Driver Module, Hi Band (Band II).177

PA Module........................178

RF Quarter Modules...............180

Low Band Quarter Module..........180

High Band Quarter Module.........181

Quarter Module Bias..............182

Protection, Cntrl & Monitor......183

Module Status LEDs...............184

Red LED Fault Blink Codes........185

Module Troubleshooting.........186

Platinum Module Test Fix......187

Troubleshooting-Module Swap....189

Troubleshooting Blink Codes....189

Isolating Other Failures.......194

Locating Failed RF FETs........196

DC Resistance Test.............196

Idle Current Test..............196

Parts Replacement Proced.......197

Soldering Precautions..........197

Quarter Module Replacemnt......199

RF FET Replacement.............200

Testing and Replacing Iso Res..204

Pass FET Replacement...........204

Chip Cap Replacement...........205

Test Procedure TV Modules......205

Pre-operational Checks.........205

Initial Power Up...............205

Idle Current Check.............205

Over/Under Voltage Check.......206

RF Testing.....................206

Application of Drive...........207

Gain Check.....................207

ISO Volts Check................208

Overdrive Check................208

VSWR Protection Check..........210

Section 9

50 Volt Supply

Introduction...................213

Theory of Operation............213

Transformer Primary............213

Six Phase SCR Rectification....214

DC Supply Filtering............214

Control Board..................214

Controller Power Supply........215

50 V Supply Regulation Ckt.....215

Fault Protection Circuits......216

GO / NOGO Circuit..............216

Troubleshooting and Maint......217

Over-temp Fault................218

Over-voltage...................219

Over-current...................219

Breaker Trips..................219

Slave Cntrlr PS Fault Indicat..219

Delay Angle Balance Adjust.....220

Vendor Repair..................229

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NOTES:

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Section 1 1

Platinum-i Series Analog

Transmitter Introduction

______________________________________________________________________

1.1 Introduction

This manual is desrcibes the Harris Analog Platinum-i

TM

series of solid state VHF

transmitters which include the following models with their peak sync power ratings.

Larger models are available by request. Each model is rated for 10% aural.

MODEL POWER MODEL POWER

HT15HS/LS 15 KW HT10HSP 10 KW

HT11LSP 11 KW

HT30HS/LS 30 KW HT20HSP 20 KW

HT22LSP 22 KW

HT45HS/LS 45 KW HT30HSP 30 KW

HT33LSP 33 KW

HT60HS/LS 60 KW HT40HSP 40 KW

HT44LSP 44 KW

1.1.1 Transmitter Configurations

The Platinum-i series contains a separate intelligent control cabinet that can be used in

multiple Platinum Analog transmitter configurations.

There are 2 basic PA cabinet configurations: Standard and Parallel Path. In Standard

configuration; a separate PA cabinet houses vision Driver(s), vision Driver PAs, sound

Driver(s), and the sound PAs. This cabinet is often referred to as the Aural/Driver

Cabinet or Sound/Driver Cabinet. In addition to the Aural/Driver Cabinet are 15kW

vision PA building block cabinets. A 30kW system would include 1 Aural/Driver Cabinet

plus two 15kW vision PA cabinets. In Parallel Path configuration there is no separate

Aural/Driver cabinet. Instead, each PA Cabinet contains vision and sound Drivers, vision

Driver PAs plus sound PAs resulting in 10kW building block cabinets. Thus a 20kW

system would have 2 PA cabinets plus the Control Cabinet.

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NOTE:

The HT60HS/LS Standard configuration system uses 2 Aural/Driver cabinets.

1.1.2 Organization of Transmitter Documentation

• The documentation consists of:

a. Platinum-i Analog Technical Manual (this manual)

b. Platinum-i Analog Drawing Package for High Band or for Low Band

c. HX1V Exciter Manual (a separate manual and drawing package).

• Organization of the Technical Manuals

The text part of the manual is divided into the following sections.

Section 1: Introduction

Section 2: Hardware Installation

Section 3: Software Installation and Setup

Section 4: Operation

Section 5: Control System Theory of Operation

Section 6: Control Cabinet

Section 7: PA Cabinet

Section 8: RF Modules

Section 9: 50 Volt Power Supply

Section 10: Parts Listing

There are different drawing packages for low band and high band systems: the drive

chains and modules are different. The drawing packages are organized in sections with

tab separators as follows:

10K SYSTEM or 15K SYSTEM COMMON SUBSYSTEMS

100 HT10H/11LSP i HT15H/LS i 600 Control System

200 HT20H/22LSP i HT30H/LS i 700 Control Cabinet

300 HT30H/33LSP i HT45H/LS i 800 PA Cabinet

400 HT40H/LSP i HT60H/LS i 900 50 Volt Power Supply

500 NOT USED 1000 High Power RF Modules

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Figure 1- HT10HSi/LSi

1.2 General Description

The Analog Platinum-i

TM

consists of a control cabinet, one or more power amplifier

cabinets (PA). and RF output system. The RF system includes a color notch filter,

harmonic filter and a vision plus sound RF combiner feeding the antenna.

The eCDi version of the control cabinet will be used with new Platinum-i cabinets and

as a retrofit to older PA cabinets. The different versions of the PA cabinet will use

various drive configuration and different modules types.

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Another use will be to retrofit existing analog transmitters to digital service. These

PAs will continue to use the 12 or 17 visual PA module configuration as the digital

power amplifier.

Platinum Series transmitters employ rugged field effect transistors (FETs), parallel

amplifier modules, multiple power supplies, and a high-resolution flat display screen for

monitoring.

The control and monitor system includes storage of fault events with time, date, and

description. VSWR foldback automatically reduces power during high VSWR operation,

such as that encountered with antenna icing.

Available options include dual exciters, an automatic exciter switcher, and redundant

control power supplies.

Each transmitter consists of a control cabinet and one or more amplifier cabinets.

Transmitters from 1-10 kW have a single amplifier cabinet containing the aural path, the

visual drive chain, and the visual final. 20 kW transmitters have two amplifier cabinets like

those used in the 10 kW transmitter.

15 kW transmitters have two amplifier cabinets: one for the aural path and visual drive

chain, and one for the visual final. 30 kW transmitters have one cabinet for aural path and

visual drive chain, and two 15 kW visual final cabinets. 45kWunits have two aural

path/visual drive chain cabinets and three 15 kW visual finals. Finally, 60 kW transmitters

have six cabinets, doubling the 30 kW architecture.

In transmitters with multiple visual amplifier cabinets, outboard hybrids are used to

combine the outputs of the visual finals. Optional notch or hybrid diplexers are available

for all models to combine aural and visual signals to permit using a common antenna

system.

1.2.1 AC Power Distribution

Refer to AC Power Distribution drawing for the following discussion. Each cabinet has its

own AC power source. Control cabinet breaker CB-1, located behind the control panel left

of the controller boards, protects the wiring in the control cabinet (see Figure 1-1). A phase

monitor guards against low voltage, loss of one phase, and reversal of the phase

sequencing. Line voltage samples are provided for the system monitor. All logic supplies,

exciter power and fan in the control cabinet are controlled by CB-1.

Each amplifier cabinet’s AC power is fed through CB-1 to the logic supply (see Figure 1-

3). AC Contactor K-1 feeds the 50 volt supplies and fan breaker CB-2 (see Figure 1- 4).

Aux relay K-2 activates the AC contactor through commands from the slave controller.

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1.2.2 Transmitter Control System

See Figure 1-5. The control system for the transmitter consists of a main controller

mounted in the control cabinet, plus individual slave controllers mounted in each amplifier

cabinet. Data from the system is interfaced through the monitor board to the display

controller, and shown on the front panel flat display screen as bar graphs and numerical

readings. Transmitter ON/OFF, LOCAL/REMOTE, and power RAISE/LOWER switches

are located on the control cabinet, to the right of the display panel.

1.2.3 Display Panel

The main control system samples each cabinet and gathers all of the status and analog data

for the display. The touch screen display is part of a monitoring computer and the main

controller will continue operation of the transmitter when this computer has a fault. The

control panel indicators back up the touch screen and operation button back up the touch

screen button functions.

1.2.4 Main Controller

The transmitter main control unit provides a central point for control and monitoring the

entire system. The main controller interfaces with the slave controller(s) for the amplifier

cabinets’ ON/OFF commands, and with the exciter for power RAISE/LOWER commands.

Peak detectors collect aural and visual RF samples and send them to the main controller for

power metering. The main controller also directs VSWR foldback action.

The main controller has a battery backup to restore the transmitter to its previous operating

condition after a temporary AC power failure. A power down timer will automatically turn

the transmitter off if the power is not restored within approximately two hours. Remote

status and analog outputs are provided by the main controller to a series of D connectors in

the rear of the control cabinet.

1.2.5 Slave Controllers

The slave controllers are mounted in the upper left-hand slot of each amplifier cabinet.

Each is responsible for controlling and monitoring its PA cabinet. The controllers interface

the cabinet to the main controller and monitor in the control cabinet.

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Figure 1-5, Control System Block Diagram

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WARNING: Disconnect and lockout AC primary power prior to servicing

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Each slave controller controls a cabinet’s fan motor, 50 volt DC supplies, and RF amplifier

modules. Slave controllers also report cabinet door interlock status, air interlock status,

module faults, and power supply faults to the main controller.

Cabinet input drive and RF power output samples, detected by RF peak detectors, are

relayed to the main controller through the slave controllers as well.

In the event of loss of the main controller, each slave may be used to operate its amplifier

cabinet for emergency service.

1.2.7 50 Volt Power Supplies

Each PA cabinet has one or two 50 volt supplies, depending on system configuration.

These supplies convert the AC power to 50 volts DC for the RF amplifier modules. Each is

rated at 300 amps, and regulated to hold the transmitter power stable despite power line

voltage changes. Internal fault protection is interfaced to the slave controller.

1.2.8 RF Amplifier Modules

Only two types of RF amplifier modules are used in the aural and visual chains of any

given Platinum transmitter system:

1.2.8.1 Power Amplifiers (PAs)

PAs are used primarily as final amplifiers. Each is capable of supplying 1,050 watts RF

output, either aural CW or visual peak sync. PAs are also used as inter-stage amplifiers in

larger visual cabinets, to drive several subsequent parallel PA modules. PAs are single-

stage amplifiers, consisting of paralleled class AB amplifiers.

1.2.8.2 Driver Modules

Driver modules provide high gain. Primarily used in preamp applications to drive PAs, they

are also used as aural final amplifiers in low power applications. Driver modules are keyed

so that they cannot be plugged into a PA slot.

Low band drivers contain two cascaded class A stages. High band drivers contain two class

A stages and one class AB stage. In both cases, the final stage in a driver consists of two

paralleled amplifier blocks.

1.2.9 Visual Signal Flow Path

A basic visual signal flow topology is common to all Platinum Series transmitters. For the

following discussion, refer to the transmitter block diagram in the drawing package.

1.2.9.1 Exciter

Video is applied to the exciter where it is clamped, pre-corrected for differential gain and

differential phase, and modulated onto the IF carrier (37 MHz for system M/NTSC,

38.9MHz for B/PAL). Next, frequency response and group delay are corrected. Vestigial

sideband filtering follows. The IF signal then passes through an AGC amplifier to

correctors for linearity and ICPM. A local oscillator and mixer in the exciter upconvert the

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Harris Intelligent Transmitter Platinum-i Series Technical Manual

Harris Intelligent Transmitter Platinum-i Series Technical Manual

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