AR worldwide 2000TP8G18M1 Service manual

Operating and
Service Manual
2000TP8G18M1
Model
1013824-502
Part Number
Serial Number

EC Declaration of Conformity
We; Amplifier Research
160 School House Road
Souderton, PA 18964
declare that our product;
the Model 2000TP8G18 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

INSTRUCTIONS FOR SAFE OPERATION
BEFORE APPLYING POWER
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.
HAZARDOUS RF VOLTAGES
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.
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.
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.
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.
RANGE OF ENVIRONMENTAL CONDITIONS
This equipment is designed to be safe under the following
environmental conditions:
•Indoor use
•Altitude up to 2000M
•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.
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.

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.

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 .................................................................................... 7
2.1 Design of the Amplifier............................................................................................. 7
2.2 Description of the RF Circuit (A30986-000) ............................................................ 7
2.3 Description of the Power Supply (A30984-000)....................................................... 8
3. OPERATION........................................................................................................... 11
3.1 Warnings and Cautions............................................................................................ 11
3.2 Installation ............................................................................................................... 12
3.2.1 Unpacking ............................................................................................................ 12
3.2.2 Mounting and removing ....................................................................................... 12
3.2.3 Cooling Requirements .......................................................................................... 13
3.2.4 AC Line Power Connections ................................................................................ 13
3.2.5 RF Connections .................................................................................................... 13
3.2.6 External Interlock Connector ............................................................................... 14
3.2.7 Video Input (Pulse Gate) Connection................................................................... 14
3.2.8 Optional External Filter/Switch Connection ........................................................ 14
3.3 Front Panel Features ................................................................................................ 16
3.4 Front Panel Display and Soft Keys ......................................................................... 17
3.5 Rear Panel Features ................................................................................................. 21
3.6 Initial Turn On and Warm-up Procedure................................................................. 22
3.7 Remote IEEE-488 Operation................................................................................... 23
3.8 TWTA General Considerations ............................................................................... 29
4. MAINTENANCE..................................................................................................... 31
4.1 Safety Warning........................................................................................................ 31
4.2 Unauthorized Repairs .............................................................................................. 31
4.3 Preventive Maintenance .......................................................................................... 31
4.4 Troubleshooting....................................................................................................... 32
4.5 Non-Repairable Modules......................................................................................... 33
5. TECHNICAL DOCUMENTATION ..................................................................... 35
5.1 Top Level Build Tree .............................................................................................. 37
5.2 Schematics............................................................................................................... 39
5.3 Parts Lists ................................................................................................................ 41
5.3.1 Parts List, HPA Logic and Control Module, A16485-000 ................................... 42
5.3.2 Parts List, Pulsed TWT Power Supply, A22826-344........................................... 44
5.3.3 Parts List, Remote Control Board, Foldback Only (Emergency Bypass Board),
A24830-000.......................................................................................................... 45
5.3.4 Parts List, Remote Control Board (Emergency Bypass Board), A24830-001 ..... 46
5.3.5 Parts List, HPA Interface Board, Plastic, A25444-000 ........................................ 47
i

Model 2000TP8G18
5.3.6 Parts List, Harmonic Filter Switching Kit, Two Filters, (200W IJ External
Filters), A30529-000.............................................................................................50
5.3.7 Parts List, Harmonic Filter Switching Kit, One Filter (200W IJ External
Filter Switching), A30529-001 .............................................................................51
5.3.8 Parts List, RF Components, 23PIJ Supertube, A30983-000.................................52
5.3.9 Parts List, Power Supply, 2KW Pulsed IJ Band, A30984-000 .............................53
5.3.10 Parts List, TWTA 2KW Pulsed IJ Band (AR), A30985-000..............................54
5.3.11 Parts List, Wiring Kit, 23PIJ, Single Phase, A31049-000 ..................................55
5.4 Recommended Spare Parts.......................................................................................57
5.5 Sample Program for IEEE-488 Communication......................................................58
Appendix Application Note 35: Pulse TWTAs..........................................................59
1.0 Introduction..............................................................................................................59
2.0 Unique Specification for Pulse TWTAs ..................................................................60
2.1 Delay, RF Rise and Fall time and the PULSE INPUT.............................................60
2.2 Pulse Width..............................................................................................................61
2.3 Pulse Rate.................................................................................................................61
2.4 Duty Cycle ...............................................................................................................62
2.5 Pulse Off Isolation ...................................................................................................62
2.6 Noise Power Density................................................................................................62
2.7 Forward and Reflected Peak Power .........................................................................62
3.0 Summary ..................................................................................................................62
FIGURES
Figure 3-1 Mounting Support Holes ................................................................................12
Figure 3-2 Front Panel Features .......................................................................................16
Figure 3-3 Front Panel Display Screens...........................................................................17
Figure 3-4 Rear Panel Features ........................................................................................21
Appendix: Figure 1...........................................................................................................60
Appendix: Figure 2...........................................................................................................61
TABLES
Table 3-1 Front Panel Features ........................................................................................16
Table 3-2 Rear Panel Features..........................................................................................21
Table 3-3 Catalog of IEEE-488 Commands.....................................................................24
Table 3-4 Catalog of Status Codes ...................................................................................25
Table 3-5 Catalog of Fault Codes.....................................................................................26
Table 3-6 Catalog of System State Codes ........................................................................27
Table 3-7 Catalog of *STA?; Response Codes ................................................................27
Table 3-8 Catalog of *STB?; Response Codes ................................................................28
Table 3-9 Catalog of Heater Auto Off Time Delay Codes...............................................28
ii

1. DESCRIPTION AND SPECIFICATIONS
This manual provides operating, interfacing and selected service information pertinent to Amplifier
Research Model 2000TP8G18 Broadband Microwave Amplifier. The Model 2000TP8G18 is a 2,000
watt pulse only IJ band traveling-wave tube amplifier (TWTA).
1.1 TWTA DESCRIPTION
The amplifier uses a broadband traveling-wave “supertube” assembly that consists of two traveling wave
tubes (TWTs) that are power combined to provide a minimum of 2,000 watts peak pulsed output power over
the amplifier's full bandwidth. The amplifier is well suited for pulse susceptibility and general laboratory
testing where instantaneous bandwidth and high gain are required.
For bench top use the amplifier is supplied in an enclosure with integral carrying handles.
The amplifier is completely self-contained in a single unit housed in a standard 19 inch rack cabinet 14 inches
high and approximately 26 inches deep. It is packaged in two sub-enclosures: a power supply/control module
that is 8.75” high, and an RF power unit (the “supertube”) that is 5.25” high. The sub-enclosure packages are
connected together with side plates to form the amplifier. They are interconnected by a low voltage cable. The
two sub-enclosures are completely open to one another on the inside of the unit to allow for HV
interconnects.
Primary power is 190-260VAC, 50/60 Hz, single phase. An efficient switching power supply design provides
minimum power consumption. In addition, the TWTs in the supertube module are provided with dual
collectors to minimize prime 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 enclosure are interlocked to reduce the likelihood of
accidental contact with high voltage.
1.2 SUGGESTED APPLICATIONS
•Pulse RF Susceptibility testing
•Antenna and component testing
•Equipment calibration
•General laboratory pulse RF 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.
Rev - 1

Model 2000TP8G18
2
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.

160 School House Road, Souderton, PA 18964-9990 US
A
Phone [phone]•FAX [phone]
MODEL 2000TP8G18,
M1
2000 WATTS PULSE
7.5 – 18 GHz
The Model 2000TP8G18 is a self contained, forced air cooled, broadband traveling wave tube (TWT)
microwave amplifier designed for pulse applications at low to moderate duty factors where
instantaneous bandwidth, reduced harmonics and high gain are required. A reliable TWT subsystem
provides a conservative 2000 watts minimum peak RF pulse power at the amplifier output connector.
Stated power specifications are at the fundamental frequency.
The amplifier's front panel digital display shows forward and reflected average power output or
forward and reflected peak power, 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
average or peak reflected power warning and remote. Standard features include a built-in IEEE-488
(GPIB) interface, 0 dBm input, TTL Gating, 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, the Model 2000TP8G18 provides readily available pulsed
RF power for a variety of applications in Test and Measurement, (including EMC RF pulse
susceptibility testing), Industrial and University Research and Development, and Service
applications. AR also offers a broad range of amplifiers for CW (Continuous Wave) applications.
See model configurations for external harmonic filters.
0
1000
2000
3000
4000
5000
WATTS
6 8 10 12 14 16 18 20
FREQUENCY (GHz)
2000TP8G18 TYPICAL POWER OUTPUT
PEAK PULSE
REV121304

SPECIFICATIONS
Model 2000TP8G18
POWER (fundamental), PEAK PULSE, @ OUTPUT CONNECTOR
Nominal ........................................................................................................... 2500 watts
Minimum ......................................................................................................... 2000 watts
FLATNESS.......................................................................................................... ±8 dB maximum, equalized for
±3 dB maximum at rated power
FREQUENCY RESPONSE ................................................................................ 7.5 – 18 GHz instantaneously
INPUT FOR RATED OUTPUT.......................................................................... 1.0 milliwatt maximum
GAIN (at maximum setting)................................................................................ 63 dB minimum
GAIN ADJUSTMENT (continuous range) ........................................................ 35 dB minimum
INPUT IMPEDANCE ......................................................................................... 50 ohms, VSWR 2.5:1 maximum
OUTPUT IMPEDANCE ..................................................................................... 50 ohms, VSWR 2.5:1 typical
MISMATCH TOLERANCE................................................................................Output pulse width foldback protection at peak reflected power
exceeding 1000 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.
PULSE CAPABILITY
Pulse Width...................................................................................................... 0.07 – 30 microseconds.
Pulse Rate (PRF))............................................................................................ 100kHz maximum
Duty Cycle........................................................................................................ 4% maximum
RF Rise and Fall ............................................................................................. 30 ns max (10% to 90%)
Delay .............................................................................................................. 300 ns maximum from pulse input to RF 90%
Pulse Width Distortion .................................................................................... ±30 ns max (50% point of output pulse width compared
to 50% points of input pulse width).
Pulse Off Isolation........................................................................................... 80 dB minimum, 90 dB typical
NOISE POWER DENSITY (pulse on) ............................................................... Minus 55 dBm/Hz (maximum) , minus
58 dBm/Hz(typical)
(pulse off) ............................................................... Minus 140 dBm/Hz (typical)
HARMONIC DISTORTION...............................................................................Minus 18 dBc maximum, Minus 20 dBc typical
PRIMARY POWER............................................................................................. 190-260 VAC, single phase
50/60 Hz
3 KVA maximum
CONNECTORS
RF input ....................................................................................................... Type N female on rear panel
RF output ..................................................................................................... Type WRD 750D24 waveguide flange on rear panel
RF output sample port ................................................................................. Type N female on rear panel
Pulse input ................................................................................................... Type BNC female on rear panel
GPIB ............................................................................................................ IEEE-488 female on rear panel
Interlock....................................................................................................... DB-15 female on rear panel
COOLING............................................................................................................ Forced air (self contained fans), air entry and exit
in rear.
WEIGHT.............................................................................................................. See Model Configuration.
SIZE (W x H x D)................................................................................................ See Model Configuration. See Note 1.

2000TP8G18 Model Configurations
Description Weight Size (W x H x D)
(Note 1)
Model Number
2000TP8G18 72 kg
(170 lb)
50.3. x 39.37 x 77.5 cm
19.8 x 15.5 x 30.5 in.
Supplied with one TF type filter and switch kit to offer harmonics
minus 25dBc maximum at the output of the kit. (See Note 2)
91 kg
(200 lb)
50.3. x 39.37 x 77.5 cm
19.8 x 15.5 x 30.5 in.
2000TP8G18M1
NOTE 1: Dimensions shown are for TWTA only, without kits and filters.
NOTE 2: TF type filters are externally mountable harmonic filters. Refer to filter TF type specification below. Also supplied with a switch
kit that allows user to select an appropriate band, high (which bypasses filter) or low (which applies filter), via this TWTA.
Insertion loss when used with filter is maximum 1.5 dB.
FILTER TYPE SPECIFICATIONS
Microwave
Filter Model
For Use with
AR TWTA
Model
Pass
Band
(GHz)
Insertion
Loss(dB
max)
Reject
Band
(GHz)
Rejection
(dB min)
Power
(fundamental
& harmonic,
watts, max)
Input
Connector
Output
connector
Size
L x W x D
(cm, in,
typical)
Weight
(kg, lbs
typical)
Input
VSWR in
Pass
band
(typical)
Input
VSWR in
Reject
band
(typical)
TF type
filter 1
2000TP8G18
with
WRD750D24
waveguide
flange,
requires one
filter
7.5 - 12.4 0.5 15 - 36 25 200 & 10
average,
5000 & 150
peak
WRD750D24
waveguide
flange
WRD750D24
waveguide
flange
30 x 18 x 15
12 x 3 x 6
4.5, 10 1.3:1 2.5:1

2. THEORY OF OPERATION
2.1 DESIGN OF THE AMPLIFIER
The Model 2000TP8G18 TWT amplifier consists of three main parts, the supertube, the power supply, and
the control. These will be described in greater detail below.
The heart of the microprocessor control system is the control head assembly (A22933-300), which consists of
the CPU board (A18450-006) and the data link board (A22488-001). 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. Communication from the front panel is
through the HPA display board (A22700-900).
The control head is provided with its own power supply and, other than through the IEEE-488 interface bus,
is electrically isolated from the amplifier. Communication with the amplifier is via fiberoptic links to the HPA
interface board (A25444-000).
2.2 DESCRIPTION OF THE RF CIRCUIT (A30986-000)
The TWTA consists of two stages of RF amplification: a solid-state preamp assembly with adjustable gain
(E01415-000) and the dual traveling-wave tube “Supertube” assembly (A30983-000).
The “Supertube” consists of a pair of 1,500-watt pulse only TWTs (E01449-000). Each tube is mounted on its
own heat sink and cooled with its own 400 Hz fan powered by its own fan driver (A23692-000). The single
Type N precision RF input connector is located on the rear panel. The RF input is fed to the input connector
on the solid state preamplifier. The solid state preamp's output drives the RF input of the TWT module via the
external low voltage cable that connects the power supply chassis to the RF chassis. The solid state preamp
includes a voltage controlled variable gain feature that permits control of the preamp’s output power from the
control module. The preamp’s output is then split by a 180° hybrid. The hybrid’s sum port is terminated, and
the secondary ports are run to the RF inputs of each TWT via line stretchers. The line stretchers have been
adjusted to make the electrical length of the two TWTs identical for instantaneous phase combining across the
band. This phase matching is done at the factory and is transparent to the user.
Each TWT’s type WRD-750D24 output flange is connected by waveguide to the side port of a magic tee
(waveguide 180° hybrid) (E20399-000). The sum port is terminated with a 500-watt load. The difference port
is connected to a dual directional coupler, whose output flange forms the RF output of the TWTA. Because
the two TWTs in the RF chassis share a common power supply, protective circuits, and RF input and output,
the two TWTs serve in the system like a single TWT (“supertube”). The major differences between a
conventional power supply and a supertube power supply is the dual grid modulators used in a supertube
supply (to allow the two tubes to use the same cathode and collector supply, sometimes different grid voltages
must be used), and an additional temperature reading.
Since the fundamental frequencies are amplified 180° out of phase, the second harmonic products, which
represent significant power in the lower part of the band, are largely in phase, and are dumped in the sum
port. The residual harmonics are generally lower than –20 dBc, low enough in power that they can be blocked
by a reflective filter without harm to the TWTs.
An optional external harmonic filter / switch assembly may be used to further reduce harmonic power in a
sub-band. The TWTA output connects to the input of a two-position switch via a straight piece of waveguide.
Rev - 7

Model 2000TP8G18
Switching is controlled locally, through the TWTA front panel, or remotely over the TWTA’s GPIB interface.
The switch routes the RF to the appropriate band depending upon the sub-band selected:
•LOW band selection: routes to a low pass filter for operation from 7.5 – 12.4 GHz.
•HIGH band selection: routes to a low pass filter or straight piece of waveguide for operation from 12.4–
18.0 GHz.
The reflected signal from the directional coupler is connected through a -10 dB coupler to a detector diode,
whose output is used for VSWR protection by the power supply logic board, for VSWR measurement in the
leveling loop, and for reflected power measurement on the HPA interface board.
The VSWR detection and reflected power Foldback circuit is provided to protect the tube from high reflected
peak power that may result from progressive failure or mismatch of the output load. The Foldback circuit
reduces the maximum pulse width of the output signal when the reflected power exceeds the factory set value.
FOLDBACK ACTIVE appears on Menu 1 of the front panel display when the Foldback activates. When the
reflected power is below the Foldback setting, the Foldback circuit de-activates.
The forward port output is split by a -10 dB coupler. The direct output is connected to a detector diode via a
pad. The output of the detector diode is used on the HPA interface board to measure forward power. The side
port of the coupler is connected to the forward type N precision RF sample port on the rear panel.
Forward and reflected power monitoring, both peak reading and average reading, are designed for use when a
CW RF input is present during the entire period of the pulses applied to the external pulse input.
Amplifier gain is determined by the solid state pre-amp (SSPA), 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 SSPA attenuator. The emergency bypass board mounted behind the front
panel is provided with a circuit for control head bypass in the event of a failure. In emergency bypass
operation the attenuator signal is provided locally by means of a potentiometer on the emergency bypass
board.
RF pulsing characteristics are protected by the Pulse Monitor Board (A30750-000). This board protects the
HPA from over duty and over pulse width operation. The settings of these faults are factory set prior to
shipment. This board also allows for user settable warnings for over peak forward or reflected power. These
warnings can be set locally or remotely.
2.3 DESCRIPTION OF THE POWER SUPPLY (A30984-000)
The TWT power supply provides cathode, heater, grid, and collector power for both tubes in the Supertube
assembly. The power supply chassis contains the TWT power supply assembly (A22826-344), an HPA
interface board (A25444-000), a pulse monitor board (A30750-000), the HPA control head and a front panel
circuit breaker. In addition, the chassis has a 400 Hz cooling fan and a fan inverter (A23692-000). The power
supply assembly is of modular construction. Low voltage power for logic and for control of the entire power
supply assembly is provided by the low voltage power supply module (A23687-150). Control logic and TWT
protection circuits are contained in the HPA logic and Control Assembly (A16485-000).
The Heater Power Supply Module (A23724-000) powers the DC heaters of both TWTs. Bias and pulse top
voltage for the TWT grid are provided by the Modulator Assembly (A23684-100 and A23684-101), one
modulator per tube.
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
8 Rev -

Model 2000TP8G18
Board Assembly (A16487-382), and switching is controlled by the Regulation Board. The high voltage
transformer and rectifiers are contained in the HV Rectifier (A21425-021). The high voltage DC is filtered in
the HV Filter Assembly (A21458-004).
Interconnects between the power supply modules are either through a motherboard or interconnected wiring
harnesses. The motherboard is installed in the power supply base plate so that the entire area of the finned
heat sink is available for heat transfer. The cooling air is provided by a 400 Hz fan. Air enters through the air
intake filter on the rear panel. The Motherboard assembly is A23280-000.
The HPA interface board permits the control module to control the power supply and monitor analog values
and fault status. Control is through the F/O to RS-485 board, which converts the electrical data from the
control module back to fibers to the HPA interface board.
Rev - 9

Model 2000TP8G18
10 Rev -