Amplifier Research 200T4G18 Service manual

Operating and
Service Manual
20T4G18
Model
1008254-501
Part Number
Serial Number
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Model 20T4G18
2
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EC Declaration of Conformity
We; Amplifier Research
160 School House Road
Souderton, PA 18964
declare that our product;
the Model 200T4G18 amplifier
to which this declaration relates is in compliance with the requirements of the EEC EMC
Directive (89/336/EEC) and Low Voltage Directive (73/23/EEC) in accordance with the
relative standards listed below:
EMC:
EN 50082-1: 1992
Electromagnetic compatibility – Generic immunity standard
EN 50081-1: 1992
Electromagnetic emissions requirements for Industrial, Scientific, and
Medical (ISM) Equipment
Safety:
EN 60950 (1995)
The CE marking is affixed on the device according to the EC Directives.
Donald R. Shepherd
President
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INSTRUCTIONS FOR SAFE OPERATION
BEFORE APPLYING POWER SAFETY SYMBOLS
This symbol is marked on the equipment
when it is necessary for the user to refer to
the manual for important safety information.
Dangerous voltages are present. Use extreme
care.
CAUTION: The caution symbol denotes a
potential hazard. Attention must be given to
the statement to prevent damage, destruction,
or harm.
Indicates protective earth terminal.
Review this manual and become familiar with all safety
markings and instructions.
Verify that the equipment line voltage selection is
compatible with the main power source.
Protection provided by the equipment may be impaired if
used in a manner not specified by Amplifier Research.
INTENDED PURPOSES
This equipment is intended for general laboratory use in a
wide variety of industrial and scientific applications. It is
designed to be used in the process of generating, controlling,
and measuring high levels of electromagnetic Radio
Frequency (RF) energy. Therefore, the output of the amplifier
must be connected to an appropriate load such as an antenna
or field-generating device. It is the responsibility of the user to
assure that the device is operated in a location which will
control the radiated energy such that it will not cause injury
and will not violate regulatory levels of electromagnetic
interference.
RANGE OF ENVIRONMENTAL CONDITIONS
This equipment is designed to be safe under the following
environmental conditions:
HAZARDOUS RF VOLTAGES • Indoor use
• Altitude up to 2000M
The RF voltages on the center pin of the RF output connector
can be hazardous. The RF output connector should be
connected to a load before AC power is applied to the
amplifier. Do not come into contact with the center pin of the
RF output connector or accessories connected to it. Place the
equipment in a non-operating condition before disconnecting
or connecting the load to the RF output connector.
• Temperature of 5°C to 40°C
• Maximum relative humidity 80% for temperatures up to
31°C. Decreasing linearly to 50% at 40°C.
• Main supply voltage fluctuations not to exceed ± 10% of
the nominal voltage or minimum and maximum
autoranging values.
• Pollution degree 2: Normally non-conductive with
occasional condensation. While the equipment will not
cause hazardous condition over this environmental range,
its performance may vary.
SAFETY GROUND
This equipment is provided with a protective earth terminal.
The main power source to the equipment must supply an
uninterrupted safety ground of sufficient size to the input
wiring terminals, power cord, or supplied power cord set. The
equipment MUST NOT BE USED if this protection is
impaired.
COOLING AIR
Care should be exercised not to block the cooling air inlets or
outlets. Cooling air blockage can result in damage to the RF
amplifier or intermittent shut-downs.
PHYSICAL DAMAGE
The RF amplifier should not be operated if there is physical
damage, missing hardware, or missing panels.
MAINTENANCE CAUTION
Adjustment, maintenance, or repair of the equipment must be
performed only by qualified personnel. Hazardous energy may
be present while protective covers are removed from the
equipment even if disconnected from the power source.
Contact may result in personal injury. Replacement fuses are
required to be of specific type and current rating.
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ADDITIONAL WARNINGS & NOTES
WARNING:
This equipment operates at potentially lethal voltages. Only trained,
qualified personnel should operate, maintain, or service it.
Hazardous energy may be present while protective covers are removed
from the equipment even if disconnected from the power source. Contact
may result in personal injury.
CAUTION:
Adjustment, maintenance, or repair of the equipment must be performed
only by qualified personnel.
CAUTION:
Replacement fuses are required to be of specific type and current rating.
CAUTION:
The information in this document was obtained from reliable sources and
was believed to be accurate at the time of publication. Since subsequent
modifications to the machine may have been made, use this information
only as a guide. Carefully compare the unit's actual configuration and
operation to the descriptions in this manual before you undertake to
operate, service, or modify this machine. Any variance or modification
should be noted, dated, and initialed in the discrepant part of all manuals
on hand for future reference. If you have technical or editorial comments
you wish to make to the manufacturer, please write them on photocopies
of the relevant sheets.
NOTE: The contents of this document are the property of the manufacturer and this document is delivered
on the express condition that it not be disclosed, reproduced in whole or in part, or used for manufacture for
anyone other than the manufacturer without its written consent, and that no right is granted to disclose or so
use any information in this document.
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TABLE OF CONTENTS
TABLE OF CONTENTS .................................................................................................. i
1. DESCRIPTION AND SPECIFICATIONS..............................................................1
1.1 TWTA Description.....................................................................................................1
1.2 Suggested Applications..............................................................................................1
1.3 Specifications .............................................................................................................1
1.4 Accessories.................................................................................................................1
1.5 Test Data Sheet ..........................................................................................................2
2. THEORY OF OPERATION.....................................................................................5
2.1 Design of the amplifier...............................................................................................5
2.2 Description of the RF Circuit.....................................................................................5
2.3 Description of the Power Supply ...............................................................................6
3. OPERATION..............................................................................................................7
3.1 Warnings and Cautions ..............................................................................................7
3.2 Installation..................................................................................................................8
3.2.1 Unpacking ...............................................................................................................8
3.2.2 Mounting.................................................................................................................8
3.2.3 Cooling Requirements.............................................................................................9
3.2.4 AC Line Power Connections.................................................................................10
3.2.5 RF Output Connections.........................................................................................10
3.2.6 External Interlock Connector ................................................................................10
3.3 Front Panel Features.................................................................................................11
3.4 Front Panel Display and Soft Keys ..........................................................................12
3.5 Rear Panel Features..................................................................................................16
3.6 Initial Turn On and Warm-up Procedure .................................................................16
3.7 Emergency Bypass Operation ..................................................................................17
3.8 Remote IEEE-488 Operation ...................................................................................18
3.9 TWTA General Considerations................................................................................23
4. MAINTENANCE .....................................................................................................25
4.1 Safety Warning ........................................................................................................25
4.2 Unauthorized Repairs...............................................................................................25
4.3 Preventive Maintenance ...........................................................................................25
4.4 Troubleshooting .......................................................................................................26
4.5 Non-Repairable Modules .........................................................................................27
5. TECHNICAL DOCUMENTATION......................................................................29
5.1 Top Level Build Tree...............................................................................................30
5.2 Schematics................................................................................................................31
5.3 Wiring Diagrams......................................................................................................33
5.4 Parts Lists.................................................................................................................35
5.4.1 Parts List, HPA Logic and Control Module, A16485-000....................................36
5.4.2 Parts List, Power Supply (Short) For TWT 5172, A23720-099 ...........................38
5.4.3 Parts List, Emergency Bypass Board, A24830-001..............................................39
5.4.4 Parts List, Emergency Bypass Board, A24830-002..............................................40
5.4.5 Parts List, HPA Interface Board (Plastic), A25444-000 .......................................41
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Model 20T4G18
5.4.6 Parts List, HPA 20W 4.2-18GHZ (AR), A28825-300..........................................44
5.4.7 Parts List, Microwave Power Assembly, AR, A28826-000..................................45
5.5 Recommended Spare Parts.......................................................................................46
5.6 Sample Program for IEEE-488 Communication......................................................47
ILLUSTRATIONS
Figure 3-1 - Rear View of HPA ..........................................................................................9
Figure 3-2 - TWTA Front Panel Features .........................................................................11
Figure 3-3 - Front Panel Display Screens..........................................................................12
Figure 3-4 - TWTA Rear Panel Features...........................................................................15
TABLES
Table 1 - Front Panel Features.............................................................................................9
Table 2 - Rear Panel Features............................................................................................15
Table 3 - Catalog of IEEE-488 Commands.......................................................................17
Table 4 - Catalog of Status Codes .....................................................................................18
Table 5 - Catalog of Fault Codes.......................................................................................19
Table 6 - Catalog of System State Codes ..........................................................................19
Table 7 - Catalog of *STA?; Response Codes ..................................................................20
Table 8 - Catalog of *STB?; Response Codes ..................................................................20
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1. DESCRIPTION AND SPECIFICATIONS
This manual provides operating, interfacing and selected service information pertinent to Amplifier
Research Model 20T4G18 Broadband Microwave Amplifier. The Model 20T4G18 is a 20 watt C/I/J
band traveling-wave tube amplifier (TWTA).
1.1 TWTA DESCRIPTION
The amplifier uses a broadband micro- traveling-wavetube (TWT) to provide 20 watts minimum output over
the TWT amplifier's full bandwidth. The amplifier is well suited for susceptibility and general laboratory
testing where instantaneous bandwidth and high gain are required.
The amplifier is completely self-contained and packaged for standard 19-inch rack mounting or bench top
use. The front panel of the rack mountable amplifier is 5.25 inches high, and the overall unit is 25.25 inches
deep, excluding the rear-panel connectors. For bench top use, the amplifier is supplied in an enclosure with
integral carrying handles.
Primary power is 99-260 volts 50-60 Hz., single phase. An efficient switching power supply design provides
minimum power consumption. A fast regulation control loop and a high degree of filtering ensure
performance within specifications over a wide range of operating conditions. The amplifier is fully enclosed,
and the upper and lower panels of the rack mountable amplifier are interlocked to reduce the likelihood of
accidental contact with high voltage.
1.2 SUGGESTED APPLICATIONS
• RF Susceptibility testing
• Antenna and component testing
• Equipment calibration
• General laboratory instrumentation
1.3 SPECIFICATIONS
Refer to the Amplifier Research Data Sheet on the following pages for detailed specifications.
1.4 ACCESSORIES
Amplifier Research offers a number of accessories for use with this amplifier including:
• Directional coupler
• Antenna
• Flexible transmission line
Refer to a current Amplifier Research catalogue for Microwave Accessories.
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Model 20T4G18
1.5 TEST DATA SHEET
A Test Data Sheet for a specific unit is prepared at the time of manufacture and is included with the unit's
copy of this manual.
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160 School House Road, Souderton, PA 18964-9990 US
A
Phone [phone]•FAX [phone]
MODEL 20T4G18
M1, M2
20 WATTS CW
4.2 - 18 GHz
The Model 20T4G18 is a self contained, forced air cooled, broadband traveling wave tube (TWT)
microwave amplifier designed for applications where wide instantaneous bandwidth, high gain and
moderate power output are required. A reliable micro TWT provides a conservative 20 watts
minimum at the amplifier output connector. Stated power specifications are at fundamental
frequency.
The amplifier's front panel digital display shows forward and reflected output plus extensive system
status information accessed through a series of menus via soft keys. Status indicators include power
on, warm-up, standby, operate, faults, excess reflected power warning and remote. Standard features
include a built-in IEEE-488 (GPIB) interface, 0dBm input, VSWR protection, gain control, RF
output sample port, auto sleep, plus monitoring of TWT helix current, cathode voltage, collector
voltage, heater current, heater voltage, baseplate temperature and cabinet temperature. Modular
design of the power supply and RF components allow for easy access and repair. Use of a switching
mode power supply results in significant weight reduction.
Housed in a stylish contemporary cabinet this unit is designed for benchtop use but can be removed
from the cabinet for rack mounting. The Model 20T4G18 provides readily available RF power for a
variety of applications in Test and Measurement, (including EMC RF susceptibility testing),
Industrial and University Research and Development, and Service applications.
0
20
40
60
WATTS
2 4 6 8 10 12 14 16 18 20
FREQUENCY (GHz)
20T4G18 TYPICAL POWER OUTPUT
CW
LINEAR @ 1dB COMPRESSION
REV111804
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SPECIFICATIONS
Model 20T4G18
POWER (fundamental), CW, @ OUTPUT CONNECTOR
Nominal ........................................................................................................... 42 watts
Minimum ......................................................................................................... 20 watts
Linear @ 1dB Compression ............................................................................ 10 watts minimum
FLATNESS ......................................................................................................... ±9 dB maximum, 4.2 - 18 GHz
±5dB maximum, 8.0 - 18 GHz
FREQUENCY RESPONSE................................................................................ 4.2 - 18 GHz instantaneously
INPUT FOR RATED OUTPUT ......................................................................... 1.0 milliwatt maximum
GAIN (at maximum setting) ............................................................................... 43 dB minimum
GAIN ADJUSTMENT (continuous range)........................................................ 35 dB minimum
INPUT IMPEDANCE......................................................................................... 50 ohms, VSWR 2.0:1 maximum
OUTPUT IMPEDANCE..................................................................................... 50 ohms, VSWR 2.5:1 typical
MISMATCH TOLERANCE ............................................................................... Output power foldback protection at reflected
power exceeding 20 watts. Will operate without
damage or oscillation with any magnitude and phase
of source and load impedance. May oscillate with
unshielded open due to coupling to input. Should not
be tested with connector off.
MODULATION CAPABILITY .......................................................................... Will faithfully reproduce AM, FM, or pulse
modulation appearing on the input signal. AM peak
envelope power limited to specified power.
NOISE POWER DENSITY ................................................................................ Minus 80 dBm/Hz (maximum)
Minus 90 dBm/Hz (typical)
HARMONIC DISTORTION (at 20 watts) ......................................................... 4.2-4.5GHz; Minus 0dBc maximum,
Minus 1dBc typical
4.5-5GHz; Minus 1dBc maximum,
Minus 2dBc typical
5-7GHz; Minus 2.5dBc maximum,
Minus 4dBc typical
7- 10 GHz; Minus 5dBc maximum,
Minus 9dBc typical
10 - 12 GHz; Minus 8dBc maximum,
Minus 12dBc typical
Above 12 GHz; Minus 20dBc maximum,
Minus 30dBc typical
PRIMARY POWER ............................................................................................ 99-260 VAC
50/60 Hz single phase,
600 VA maximumn
CONNECTORS
RF input....................................................................................................... Type N female on rear panel
RF output..................................................................................................... Type TNC female on rear panel
RF output sample port................................................................................. Type N female on rear panel
GPIB............................................................................................................ IEEE-488-(f)
Interlock ...................................................................................................... DB-15 female on rear panel
COOLING ........................................................................................................... Forced air (self contained fans), air entry and exit in
rear.
MODEL CONFIGURATION
MODEL NUMBER DESCRIPTION WEIGHT SIZE (H x W x D)
20T4G18 With removable enclosure 32 kg (70lb) 50.3 x 16.5 x 68.6 cm
19.8 x 6.5 x 27 in
20T4G18M1 Enclosure removed for rack mounting, slides and front handles installed 25 kg (55lb) 48.3 x 13.3 x 68.6 cm
19.0 x 5.25 x 27 in
20T4G18M2 Shipped without an outer cabinet 23 kg (50lb) 48.3 x 13.3 x 68.6 cm
19.0 x 5.25 x 27 in
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2. THEORY OF OPERATION
2.1 DESIGN OF THE AMPLIFIER
The model 20T4G18 TWT amplifier consists of four principal subsystems. Two of these subsystems, the
microwave power assembly (A28826-000) and the TWT power supply (A23720-099) are discussed in
sections 2.2 and 2.3, respectively.
The other two subsystems are the microprocessor control system and the TWTA packaging. These both
consist of a number of subassemblies. See the build tree in section 5.1 for further information about how the
parts lists are structured.
The heart of the microprocessor control system is the control head assembly (A25403-302), which consists of
the CPU board (A25450-000), the HPA display board (A25425-001), and the data link board (A22488). The
microprocessor control system supervises the power supply, provides metering display, processes operator
front panel inputs, and enables communication with a host computer over the IEEE-488 interface.
The control head is provided with its own power supply and, other than thru the IEEE-488 interface bus, is
electrically isolated from the amplifier. Communication with the amplifier is via fiberoptic links to the HPA
interface assembly (A25444-000).
The TWTA packaging consists of cabinet assembly (A28827-000). The cooling system utilizes a DC blower
with a dedicated DC power supply.
2.2 DESCRIPTION OF THE RF CIRCUIT
The TWTA consists of two stages of RF amplification: a solid state preamp assembly with adjustable gain
(E01122-000) and a traveling-wave tube amplifier (E08137-000).
The type N RF input connector is located on the rear panel. The RF input is fed to the input connector on the
solid state preamp. The solid state preamp's output drives the RF input of the TWT. The RF output of the
TWT is a type TNC coaxial connector. The output is directed through a short cable to a -35/-35 dB dual
directional coupler. The output TNC connector of the coupler protrudes through the rear panel of the TWTA
to function as the RF output connector.
The reverse port on the directional coupler is connected to a crystal detector, whose output is used for VSWR
protection by the power supply logic board, for VSWR measurement in the leveling loop, and for reverse
power measurement on the HPA interface board.
The forward port output is split by a -10 dB coupler. The direct output is connected to a crystal detector via a
pad. The output of the crystal detector is used on the HPA interface board to measure forward power. The
side port of the coupler is connected to the RF sample port on the rear panel. With an optional reverse power
sample port on the rear panel, an additional –10 dB coupler is connected to the reverse port of the system’s
dual directional coupler. The output port of the –10 dB coupler is connected to a detector diode whose output
is used on the HPA interface board to measure reflected power and for VSWR foldback and protection. The
coupled port of the –10 dB coupler is connected to the reverse power sample port on the rear panel.
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Model 20T4G18
Amplifier gain is determined by the solid state preamp (SSA), which has a voltage-controlled attenuator. The
control head determines the output of a digital-to-analog converter (DAC) on the HPA interface board. The
output of the DAC controls the SSA attenuator. The emergency bypass board (A24830) mounted behind the
front panel is provided with a circuit that increases the attenuation so that forward power is limited to a level
on the order of 50 watts. Forward power is also limited so that reverse power does not exceed approximately
20 watts. In emergency bypass operation (see section 3.7) the gain control signal is provided locally by means
of a potentiometer on the emergency bypass board. The foldback circuit remains on line in emergency bypass
operation.
2.3 DESCRIPTION OF THE POWER SUPPLY
The TWT power supply is of modular construction. Low voltage power for logic and control of the entire
power supply assembly is provided by the low voltage power supply module (A23687-001). In addition this
module provides DC power for the HPA interface and emergency bypass boards. Control logic and TWT
protection circuits are contained in the HPA logic and Control Assembly (A16485-000).
The Heater Power Supply Module (A10010-000) powers the TWT DC heater. The Micro- TWT requires no
separate grid or anode supply.
The high voltage power supply consists of the following: the Power Factor Correction module (A23683-100)
converts line voltage to DC for the high voltage switching supply. Switching transistors are on the Power
Board Assembly (A23710-000), and switching is controlled by the Pulse Width Modulation (PWM) Board
(A10017-100). The high voltage transformer and rectifiers are contained in the High Voltage Diode/Cap
Assembly (A21457-001). The high voltage DC is filtered in the HV Filter Assembly (A21454).
Low voltage interconnects between the power supply modules are through a motherboard. It is installed in a
finned heat sink assembly to which the modules are bolted. The heat sink is cooled by the incoming cabinet
air. The Heat Sink/Motherboard assembly is A23711-000.
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3. OPERATION
3.1 WARNINGS AND CAUTIONS
Throughout this manual, the symbol:
WARNING:
indicates that a hazard exists that may result in personal injury or loss of life.
CAUTION:
indicates that failure to follow procedures may result in damage to the
equipment.
WARNING: DANGER - High Voltage Present:
Electrical equipment in this TWTA generates and stores high-voltage
energy that can result in fatal electrocution. Do not operate the TWTA
with covers or the front panel removed.
Service work must be performed only by technicians thoroughly familiar
with the high-voltages present in microwave tube amplifiers in general,
and with this equipment in particular.
Never handle the TWT leads or the high-voltage connectors unless the
unit has been unplugged and it has been positively established that the
high-voltage filter capacitors have been discharged to a known safe level.
WARNING: Safety Ground
Improper grounding of this equipment can result in electric shock. The
TWTA must be operated only with a line cord with a safety ground wire.
It is the user's responsibility to ascertain that the power connector is
properly wired and that the power outlet is grounded.
WARNING: Explosive Atmosphere
To avoid explosion, never operate this TWTA in an explosive atmosphere.
This equipment is not certified for operation in an explosive atmosphere.
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Model 20T4G18
3.2 INSTALLATION
3.2.1 Unpacking
Upon receiving the TWTA, unpack the unit and inspect it for obvious signs of external damage. If damage is
observed, notify the carrier and contact an authorized service representative.
Save and store the shipping container in case the unit needs to be returned in the future for calibration or
repair.
3.2.2 Mounting
The TWTA may be operated as a standalone benchtop unit, or it may be installed in a 19" rack.
If rack mounting is desired, first remove the amplifier from the cabinet, then install the amplifier in the rack.
CAUTION:
Due to the weight of the unit, the removal of the amplifier from the
cabinet or rack is a two person operation.
Before removal disconnect power, RF, and any other interface connectors. On the rear of the unit, remove the
six screws used to connect brackets to amplifier. On the front of the unit, remove the four screws holding the
front panel to the cabinet. Carefully slide the amplifier out of the front of the cabinet.
CAUTION:
Never rack mount the TWTA using the front panel alone. The chassis is
likely to be damaged unless its weight is supported. Bottom support rails
must be provided in a rack mount configuration.
See Figure 3-1 (on the next page) for the locations of threaded holes which may be used for supplementary
support of the rear of the TWTA.
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Model 20T4G18
USE 8-32 FH SCREWS, 3/8-1/2" THREAD IN CABINET
TO ATTACH REAR SUPPORT BRACKETS HERE
(BOTH SIDES)
100-255 VAC
SAFETY
GROUND
50/60 HZ.
500 VA
EXTERNAL
INTERLOCK
RF INPUT
0 DBM MA X
RF OUTPUT
TYPE TN C
RF SAMPLE OUT
AC POWER IN
IEEE-488
23.675
0.865
3.50
Figure 3-1. Rear View of HPA, Rack Mounting Configuration
If bottom supports are used for rack mount installation of multiple units, the amplifiers should be separated
vertically by at least 1 3/4 inches. This will allow room for necessary support rails and facilitate installation
and removal of the units.
3.2.3 Cooling Requirements
The TWTA is provided with a cooling fan. It is important that air movement around the rear of the unit be
unobstructed.
CAUTION:
For either bench or rack mounting, do not position the TWTA in such a
way that the air intake or outlet are blocked, or that the exhaust flow is
directed into the intake. See Paragraph 3.5 for location of air intake and
air outlet. If the unit is rack mounted, make sure that the intake air is
45°C or below. If necessary, fabricate a short duct to direct the hot
exhaust air out of the rack enclosure. Great care must be taken to
minimize any flow restrictions. Avoid mounting heat-producing
equipment in the same rack, especially below the TWTA. Failure to
provide adequate cooling can result in the unit's shutting down from
overtemperature conditions.
The TWTA dissipates approximately 500 watts when in the operate mode.
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Model 20T4G18
3.2.4 AC Line Power Connections
AC line power connection to the TWTA is made at the AC inlet J1, which is a female IEC-320 connector. A
line cord suitable for the type of AC outlet used, and consistent with local electrical codes, must be obtained
to mate with J1. Minimum wire size for the line cord is 18 gauge.
TWTAs destined for the North American market are provided with a terminated 3-wire cord. It plugs into
normal 120 VAC single phase outlets. The amplifier will operate from any line voltage between 99 and 260
VAC.
3.2.5 RF Output Connections
The RF output coaxial connector is type TNC female.
CAUTION:
Never operate the TWTA without a matched output load rated for at least
100 watts, continuous. The TWTA is not provided with an output
isolator. Full reflected power may irreparably damage the TWT. Even
with no drive, “looping” oscillation can result in RF output high enough to
damage the tube if it is operated without a load. The VSWR detection
and foldback circuit is provided to protect the tube from progressive
failure or mismatch of the output load; it should not be relied on for
protection from the absence of a load.
If an external isolator is installed at the output of the TWTA, either the isolator should have a load capable of
dissipating the full output of the TWTA or the isolator load should be provided with a temperature sensing
switch. The temperature switch should be normally closed, self-resetting, and with a temperature rating such
that there is no possibility of damaging the load by overheating before the switch opens. The TWTA may be
interlocked with the switch by connecting it between pins 3 and 4 of the external interlock connector (J2). If
no external isolator is used, install a jumper between pins 3 and 4. See section 3.2.6, External Interlock
Connector, below.
3.2.6 External Interlock Connector
The TWTA is provided with an external interlock capability via a 15-pin female D-sub connector, J2. To
enable the high voltage power supply, it is necessary to provide continuity between J2 pins 3 and 4. If the
amplifier shuts down because the interlock was opened, it will be necessary to reset the system to return to
standby (see System shutdown screen in Section 3.4). There is an internal jumper between J2 pins 1 and 2; a
continuity check through these pins can be used to verify the presence of the amplifier in the instrumentation
system. Users may adopt this interlock feature to disable the RF output for either equipment protection or as a
backup for personnel protection.
CAUTION:
Do not rely on the external interlock for personnel protection. The intent
of the external interlock feature is to disable the RF output for equipment
protection. Use proper operating and safety procedures to insure that
power is removed for personnel safety.
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