Page 1
Moduload® RF Load Resistor
Series 8640 and 8640B
Including Models
8645-xxx & 8646-xxx
Operation Manual
©Copyright 2016 by Bird Electronic Corporation
Instruction Book Part Number 920-8640S Rev. G
®
Moduload
, Econoload®, Econoline®, and Thruline® are
registered trademarks of Bird Electronic Corporation
Page 2
Safety Precautions
The following are general safety precautions that are not necessarily related to any specific part or procedure, and
do not necessarily appear elsewhere in this publication. These precautions must be thoroughly understood and
apply to all phases of operation and maintenance.
WARNING
Keep Away From Live Circuits
Operating Personnel must at all times observe general safety precautions. Do not replace
components or make adjustments to the inside of the test equipment with the high
voltage supply turned on. To avoid casualties, always remove power.
WARNING
Shock Hazard
Do not attempt to remove the RF transmission line while RF power is present.
WARNING
Do Not Service Or Adjust Alone
Under no circumstances should any person reach into an enclosure for the purpose of
service or adjustment of equipment except in the presence of someone who is capable of
rendering aid.
WARNING
Safety Earth Ground
An uninterruptible earth safety ground must be supplied from the main power source to
test instruments. Grounding one conductor of a two conductor power cable is not
sufficient protection. Serious injury or death can occur if this grounding is not properly
supplied.
WARNING
Resuscitation
Personnel working with or near high voltages should be familiar with modern methods of
resuscitation.
WARNING
Remove Power
Observe general safety precautions. Do not open the instrument with the power on.
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Safety Symbols
Warning notes call attention to a procedure, which if not correctly performed, could result
Caution notes call attention to a procedure, which if not correctly performed, could result
Note: Calls attention to supplemental information.
Warning Statements
Safety Precautions
WARNING
in personal injury.
CAUTION
in damage to the instrument.
The caution symbol appears on the equipment indicating there is
important information in the instruction manual regarding that particular
area
The following safety warnings appear in the text where there is danger to operating and maintenance personnel,
and are repeated here for emphasis.
WARNING
HEAVY. Do not lift this unit alone.
On page 4.
WARNING
Disconnect the unit from all power sources before servicing.
The unit may be energized from multiple sources.
The potential for electric shock exists.
On pages 5, 10, 14, 18, and 19.
WARNING
Improper wiring could result in electric shock and death.
On page 5.
WARNING
Connect the power cord to the Moduload
BEFORE connecting to AC mains.
On page 5.
WARNING
Ethylene glycol is toxic. Do not take internally.
Avoid contact with eyes, skin, and clothing. Avoid breathing vapor.
Wash thoroughly after handling.
On pages 6 and 12.
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Page 4
Moduload® RF Load Resistor
WARNING
Never attempt to connect or disconnect RF equipment from the transmission line while
RF power is being applied.
Leaking RF energy is a potential health hazard.
On pages 8 and 11.
WARNING
Disconnect from RF power sources and the AC line before any disassembly or service.
Electrical shock hazard.
On page 15.
Caution Statements
The following equipment cautions appear in the text and are repeated here for emphasis.
CAUTION
Do not block air flow. The air intake vents on the side of the heat exchanger and the
exhaust on top must not be obstructed.
On page 4.
On pages 5 and 9.
On page 5.
Use only distilled water or ethylene glycol as coolant. Do not use tap water, automotive
On page 6.
On pages 6, 9, and 12.
CAUTION
Do not operate without the interlock. Even momentary
application of RF power while coolant is not circulating could
cause immediate destruction of the load.
CAUTION
Check the local electrical code for proper AC hookup prior to operation
of the unit. Make sure the neutral or return hookup is only used
for that purpose.
CAUTION
antifreeze, sealants, or leak stopping material.
Use of these materials will damage the unit and void all warranties.
CAUTION
Operation without sufficient coolant can damage the unit.
On page 15.
iii
CAUTION
Incorrect hose connections will reverse coolant flow and could destroy the load.
Page 5
Safety Precautions
Safety Statements
USAGE
ANY USE OF THIS INSTRUMENT IN A MANNER NOT SPECIFIED BY THE MANUFACTURER MAY
IMPAIR THE INSTRUMENT’S SAFETY PROTECTION.
USO
EL USO DE ESTE INSTRUMENTO DE MANERA NO ESPECIFICADA POR EL FABRICANTE, PUEDE
ANULAR LA PROTECCIÓN DE SEGURIDAD DEL INSTRUMENTO.
BENUTZUNG
WIRD DAS GERÄT AUF ANDERE WEISE VERWENDET ALS VOM HERSTELLER BESCHRIEBEN,
KANN DIE GERÄTESICHERHEIT BEEINTRÄCHTIGT WERDEN.
UTILISATION
TOUTE UTILISATION DE CET INSTRUMENT QUI N’EST PAS EXPLICITEMENT PRÉVUE PAR LE
FABRICANT PEUT ENDOMMAGER LE DISPOSITIF DE PROTECTION DE L’INSTRUMENT.
IMPIEGO
QUALORA QUESTO STRUMENTO VENISSE UTILIZZATO IN MODO DIVERSO DA COME
SPECIFICATO DAL PRODUTTORE LA PROZIONE DI SICUREZZA POTREBBE VENIRNE
COMPROMESSA.
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Moduload® RF Load Resistor
SERVICE
SERVICING INSTRUCTIONS ARE FOR USE BY SERVICE - TRAINED PERSONNEL ONLY. TO AVOID
DANGEROUS ELECTRIC SHOCK, DO NOT PERFORM ANY SERVICING UNLESS QUALIFIED TO DO
SO.
SERVICIO
LAS INSTRUCCIONES DE SERVICIO SON PARA USO EXCLUSIVO DEL PERSONAL DE SERVICIO
CAPACITADO. PARA EVITAR EL PELIGRO DE DESCARGAS ELÉCTRICAS, NO REALICE NINGÚN
SERVICIO A MENOS QUE ESTÉ CAPACITADO PARA HACERIO.
WARTUNG
ANWEISUNGEN FÜR DIE WARTUNG DES GERÄTES GELTEN NUR FÜR GESCHULTES
FACHPERSONAL.
ZUR VERMEIDUNG GEFÄHRLICHE, ELEKTRISCHE SCHOCKS, SIND WARTUNGSARBEITEN
AUSSCHLIEßLICH VON QUALIFIZIERTEM SERVICEPERSONAL DURCHZUFÜHREN.
ENTRENTIEN
L’EMPLOI DES INSTRUCTIONS D’ENTRETIEN DOIT ÊTRE RÉSERVÉ AU PERSONNEL FORMÉ AUX
OPÉRATIONS D’ENTRETIEN. POUR PRÉVENIR UN CHOC ÉLECTRIQUE DANGEREUX, NE PAS
EFFECTUER D’ENTRETIEN SI L’ON N’A PAS ÉTÉ QUALIFIÉ POUR CE FAIRE.
ASSISTENZA TECNICA
LE ISTRUZIONI RELATIVE ALL’ASSISTENZA SONO PREVISTE ESCLUSIVAMENTE PER IL
PERSONALE OPPORTUNAMENTE ADDESTRATO. PER EVITARE PERICOLOSE SCOSSE
ELETTRICHE NON EFFETTUARRE ALCUNA RIPARAZIONE A MENO CHE QUALIFICATI A FARLA.
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Safety Precautions
CONNECT INTERLOCK TO TRANSMITTER BEFORE OPERATING.
BRANCHER LE VERROUILLAGE À L'ÉMETTEUR AVANT EMPLOI.
CONECTE EL INTERBLOQUEO AL TRANSMISOR ANTES DE LA OPERACION.
VOR INBETRIEBNAHME VERRIEGELUNG AM SENDER ANSCHLIESSEN.
PRIMA DI METTERE IN FUNZIONE L'APP ARECCHIO, COLLEGARE IL DISPOSITIVO DI BLOCCO AL
TRASMETTITORE.
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Moduload® RF Load Resistor
About This Manual
This manual covers the operating and maintenance instructions for the following models:
8640 8640B
Changes to this Manual
We have made every effort to ensure this manual is accurate. If you discover any errors, or if you have suggestions
for improving this manual, please send your comments to our Solon, Ohio factory. This manual may be periodically
updated. When inquiring about updates to this manual refer to the part number and revision on the title page.
Terminology
There are some unique terms used throughout this literature. They are defined here to clarify any
misunderstanding.
Moduload — The entire unit.
Load — The component which connects to the RF line. It is inside the HEAT EXCHANGER, connected by two hoses.
It contains the RESISTOR.
Heat Exchanger — The parts of the Moduload left when the LOAD is removed. It contains the pump, fans,
coolant reservoir, and controls.
Resistor — A subcomponent of the LOAD. This is the ceramic resistor which actually absorbs the RF power
Literature Contents.
Introduction — Describes the features of the Moduload, lists equipment supplied and optional equipment, and
provides power-up instructions.
Theory of Operation — Describes how the Moduload works.
Installation — Describes the power supply and load connection instructions.
Operating Instructions — Describes the base level operation instructions.
Maintenance — Lists routine maintenance tasks as well as troubleshooting for common problems. Specifications
and parts information are also included.
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Table of Contents
Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i
Safety Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii
Warning Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii
Caution Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
Safety Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
About This Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
Changes to this Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
Chapter 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Moduload Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Items Supplied . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Items Required but not Supplied . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Optional Items Available . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Chapter 2 Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Resistor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Flow Interlock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Thermal Interlock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Chapter 3 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Unpacking and Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
DC Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Meter Rack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Interlock Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
AC Mains Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Adding Coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Connecting RF Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Chapter 4 Operating Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Normal Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Emergency Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Chapter 5 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
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Moduload® RF Load Resistor
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Inspecting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
RF Assembly Resistance Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
DC Resistance Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Changing Coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Flushing the Coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Normal Coolant Flush . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Coolant Flush after Load Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Replacing the Fuse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Replacing the Interlock Relay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
For Model 864x . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
For Model 864xB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Replacing the Flow Switch (For Units Manufactured BEFORE 3/1/2010) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Replacing the Pressure Switch (For Units Manufactured AFTER 3/1/2010) . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Removing the Load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Model 864x . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Model 864xB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Removing the Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Servicing the Resistor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Removing the Resistor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
Inspecting the Resistor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
Removing a Fractured Resistor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Replacing the Resistor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Replacing the Conductor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Preparation for Storage or Shipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Customer Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Replacement Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Heat Exchanger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Limited Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
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Page 11
Chapter 1 Introduction
Bird 8640 and 8640B Series Moduloads are self-cooling, nonradiating, low reflection terminations for high power RF
lines. They dissipate up to 25 kW with a VSWR of less than 1.1:1 from 1 kHz to 900 MHz.
The Moduload has an interlock which triggers as a result of either high coolant temperature or low coolant flow. It
will also be active for about 2 seconds after power up or reset to ensure proper operation of the cooling system
before applying RF power.
Moduload Features
Useable with CW, AM, FM, SSB, and TV modulation, and certain pulse types. Contact Bird Electronic
Corporation for information on using Moduloads with pulsed signals.
Useable to make RF power measurements when used with a Bird 4600 or 4800 Thruline Wattmeter
Self-contained water-based cooling system
Time-delay interlock ensures steady coolant flow before RF power is applied
Indicators
Coolant Level Gauge
Items Supplied
Moduload
Instruction Manual
Power Meter Rack-Mount Kit
Items Required but not Supplied
No. 22 AWG wire, with ring terminals, for interlock connection
RF Coupling Kit
Distilled Water
Optional Items Available
Dolly (Bird P/N 6771-011) for moving the load
Ethylene Glycol, Industrial Grade, 1 Gallon - available from Bird
1
Page 12
Moduload® RF Load Resistor
Figure 1 8640 Series Moduload Outline Drawing
Figure 2 System Block Diagram
2
Page 13
Chapter 2 Theory of Operation
Resistor
Bird 8640 and 8640B Series Moduloads consist of a thin-film-on-ceramic resistor immersed in coolant. The coolant
flows directly over the resistor instead of using an intermediate heat transfer system, reducing the load size to a
minimum. After passing over the entire length of the resistor, the coolant is cooled in a forced air heat exchanger.
Coolant
The load’s electrical and thermal performance is reduced by impurities or chemical additives in the coolant,
especially ones which are deposited as scale on the resistor. This increase in the load’s thermal resistance may
cause the load to overheat and fail. Therefore, the coolant should be distilled water or a mixture of distilled water
and ethylene glycol.
When the coolant is heated, thermal expansion causes an increase in the internal pressure. The vent plugs relieves
this pressure while protecting the opening from dirt or other contaminants.
Flow Interlock
Dissipation of the heat generated by RF power is critically dependent on a minimum coolant flow of six gallons per
minute at all times, regardless of coolant temperature. When coolant flow drops below six gallons per minute, the
low flow switch or pressure switch opens causing immediate transmitter shutdown. The flow or pressure switch or
pressure switch is a “normally open” type, and is closed during normal operation.
After flow is restored, a time delay relay keeps the interlock open for an additional 2 seconds. This ensures proper
operation of the cooling system before RF power is applied to the load, preventing resistor damage or burnout.
Thermal Interlock
The Moduload is equipped with a normally closed thermoswitch which opens when the coolant temperature
exceeds 79 °C (174 °F), opening the interlock.
3
Page 14
Chapter 3 Installation
This chapter provides information on site requirements, unpacking, inspection, and preparing the Bird 8640
Moduload for use.
Unpacking and Inspection
1. Carefully inspect shipping container for signs of damage.
If the shipping container is damaged, do not unpack the unit. Immediately notify the shipping carrier and
Bird Technologies.
If the shipping container is not damaged, unpack the unit. Save shipping materials for repackaging.
2. Inspect unit for visual signs of damage.
Note: If there is damage, immediately notify the shipping carrier and Bird Technologies.
Placement
WARNING
HEAVY. Do not lift this unit alone.
CAUTION
Do not block air flow. The air intake vents on the side of the heat exchanger and the
exhaust on top must not be obstructed.
Do not use outdoors or in areas of condensing humidity.
Surrounding air must be free of contaminants or particles that could be drawn into the air intakes.
The heat exchanger must be operated in a horizontal position.
AC power is required.
Allow a minimum of one foot clearance along the sides and three feet over the top to allow unobstructed
air intake and exhaust.
In small rooms or restricted areas, outside venting is recommended. Ductwork must not have sharp bends
that would restrict air flow or create back pressure.
Mounting
The Moduload is equipped for either portable use or fixed installation. The mounting brackets on the front and rear
faces have four mounting slots arranged in a 17" x 25" rectangle (432 x 635 mm). Use a screw with a 14 inch (6.4
mm) diameter max. The brackets may be removed by removing the screws holding them to the Moduload.
4
Page 15
DC Resistance
Installation
Before first using the load, get a resistance baseline for future maintenance. Refer to
Test" on page 11
for instructions.
"RF Assembly Resistance
Meter Rack
If the Moduload will be used with a power meter, install the meter rack to provide a convenient place to keep the
meter. Use the supplied #6-32 x 14 screws to assemble the rack. To install the rack, remove two screws from the
Moduload where the rack will be mounted, then screw it into place with the supplied #8-32 x 38 screws.
WARNING
Disconnect the unit from all power sources before servicing.
The unit may be energized from multiple sources.
The potential for electric shock exists.
WARNING
Improper wiring could result in electric shock and death.
Interlock Connection
CAUTION
Do not operate without the interlock. Even momentary
application of RF power while coolant is not circulating could
cause immediate destruction of the load.
Use number 22 AWG (or heavier) wire for interlock connection. Attach solderless ring terminals to the wire
for ease of installation.
Connect the interlock wires to the interlock terminal strip as required for the transmitter.
Note: Interlock contact resistance could be as high as 10 ohms for circuits drawing less than 250 mA.
AC Mains Connection
CAUTION
Check the local electrical code for proper AC hookup prior to operation of the unit.
Make sure the neutral or return hookup is only used for that purpose.
WARNING
Connect the power cord to the Moduload
BEFORE connecting to AC mains.
The AC power supply required for this unit is 115/230 V, depending on the model, @ 50/60 Hz, 1. The unit is
equipped with an IEC 320 “cold” (70C) AC inlet.
5
Page 16
Moduload® RF Load Resistor
Coolant
WARNING
Ethylene glycol is toxic. Do not take internally.
Avoid contact with eyes, skin, and clothing. Avoid breathing vapor. Wash thoroughly
after handling.
CAUTION
Use only distilled water or ethylene glycol as coolant. Do not use tap water,
automotive antifreeze, sealants, or leak stopping material. Use of these materials will
damage the instrument and void all warranties.
Distilled water is the primary coolant for the Bird 8640. Ethylene glycol should be added to prevent bacterial growth
and freezing; 10% to 35% ethylene glycol is recommended. Using at least 10% will prevent bacterial growth and at
least 35% will protect against freezing to – 20°C.
Note: When using both ethylene glycol and distilled water, add the water first, then the ethylene gly-
col, to ensure proper mixing.
Figure 3 on page 7
following example shows the weights to make a 65% distilled water to 35% ethylene glycol mixture in 5 and 55
gallon quantities.
shows the coolant’s freezing point for a given percentage of ethylene glycol in the mix. The
5 Gal. (18.9 L) 55 Gal. (208.2 L)
Distilled Water
Ethylene Glycol
28.0 lb (12.7 kg) 310 lb (140.6 kg)
15.2 lb (6.9 kg) 167 lb (75.7 kg)
Adding Coolant
The Bird 8640 Moduload has a coolant capacity of about 9 quarts (8.5 L). To fill the coolant reservoir, follow these
steps:
CAUTION
Operation without sufficient coolant can damage the unit.
1. Ensure that the drain plug is in place.
2. Remove the filler cap on top of the heat exchanger.
3. Add about 3 quarts (2.9 L) of coolant.
4. Turn the unit on for a few seconds to draw coolant into the system.
5. Repeat steps 3 and 4 twice more, until the coolant remains steady at or just below the high mark on the level
gauge.
6. Replace the filler cap.
7. Turn the unit on and run it for five minutes to remove any air trapped in the system.
6
Page 17
Figure 3 Freezing Point of Ethylene Glycol / Distilled Water Mixture
Installation
7
Page 18
Moduload® RF Load Resistor
Connecting RF Power
After installing the Moduload, the RF transmission line can be attached using standard coaxial line coupling kits.
WARNING
Never attempt to connect or disconnect RF equipment from the transmission line
while RF power is being applied.
Leaking RF energy is a potential health hazard.
Swivel Flanged Coupling: To couple the swivel flange with a flanged RF transmission line, use an
appropriate coupling kit. Refer to
Figure 4 Swivel Flanged Coupling
Figure 4
while following the instructions below:
1. Insert the center bullet and push it in until it is fully seated.
2. Connect the coaxial input in a straight line and push carefully on the center conductor to close.
Note: The swivel flange on the load makes connection independent of the orientation of the fixed
flange on the coaxial input outer conductor.
3. Insert the bolt sets and tighten evenly all around to transmission line manufacturer’s recommended torque.
Use all of the bolts.
Unflanged Coupling: To couple the unflanged connector with an unflanged RF line, use an appropriate
coupling kit. Refer to
Figure 5 Unflanged Coupling
1. Insert the center bullet and bottom it on the midpoint nibs.
2. Position the outer sleeve, with clamping bands, over the input connector.
3. Set the transmission line snugly against the coupling stops.
4. Position the clamping bands evenly about 3/4” from the ends of the sleeve.
5. Tighten the clamping bands.
Figure 5
while following the instructions below:
8
Page 19
Chapter 4 Operating Instructions
CAUTION
Operation without sufficient coolant can damage the unit.
CAUTION
Do not operate without the interlock. Even momentary
application of RF power while coolant is not circulating could
cause immediate destruction of the load.
Normal Operation
1. Check that the coolant level is above the min. mark on the gauge.
2. Turn on the Moduload.
3. Check that the fans are running properly.
4. Wait about 2 seconds for proper coolant flow and for the interlock to close.
5. Apply RF power.
Shutdown
1. Turn off RF power at the source.
2. Wait five minutes for the system to cool to room temperature.
3. Turn off the Moduload.
Emergency Shutdown
Turn off RF power at the source.
Note: If the interlock is properly connected, RF power will be automatically turned off if a fault occurs
in the Moduload.
9
Page 20
Chapter 5 Maintenance
WARNING
Disconnect the unit from all power sources before servicing.
The unit may be energized from multiple sources.
The potential for electric shock exists.
Troubleshooting
The table below contains troubleshooting information for problems which can occur during normal operation. This
manual cannot list all malfunctions that may occur, or their corrective actions. If a problem is not listed or is not
corrected by the listed actions, notify a qualified service center.
PROBLEM POSSIBLE CAUSE CORRECTION
Heat exchanger not
operating.
Coolant leaking. Loose connections. Tighten drain plug and all connections.
Interlock opening
repeatedly.
Excessive reflected
power.
No AC power. Connected the unit to AC mains.
Unit turned off. Set the line switch to ON.
Fuse burnout. Replace fuse after correcting the
burnout cause. See
Fuse" on page 14
Worn or cracked hose. Replace defective hose.
Insufficient coolant flow. Check coolant level. Add coolant if
necessary . See
page 12
Defective flow switch. Check flow switch. See
Flow Switch (For Units Manufactured
BEFORE 3/1/2010)" on page 15
RF power too high. Lower RF power.
Ambient temperature
too high.
Air intakes or exhaust
are blocked.
DC resistance of the
load has changed.
Lower ambient temperature.
Check that clearances are at least
1 foot on the sides and 3 feet on top.
Clean panels. See
11
Check DC resistance. See
Assembly Resistance Test" on page
11
.
.
.
"Replacing the
.
"Changing Coolant" on
"Replacing the
"Cleaning" on page
"RF
.
Maintenance
WARNING
Disconnect the unit from all power sources before servicing.
The unit may be energized from multiple sources.
The potential for electric shock exists.
10
Page 21
Maintenance
Cleaning
The outside surface of the unit should be wiped free of dust and dirt when necessary. Clean the RF connector, both
metallic and insulating surfaces, with a dry, non-residue forming solvent.
If dust has collected on the radiator coils, remove the top panel and vacuum the coils. To remove the panel:
1. Remove the screws around the edge of the top panel.
2. Lift the top panel to access the fan power connector then disconnect the fan cable.
3. Remove the top panel.
Inspecting
Routinely check the load’s center and outer conductors for visible damage or excessive wear. The coolant level
should be checked once a week, more often if the Moduload is used continuously or under high ambient
temperatures. The coolant level should be above the min. mark on the gauge even when the unit is on. To add
coolant, see
"Changing Coolant" on page 12
.
RF Assembly Resistance Test
Note: These tests are by no means a necessity to the operation of the load but merely guidelines for
the users information.
Accurate measurement of the DC resistance between the inner and outer conductors of the RF input connector will
provide a good check of the condition of the load resistor.
Checking the DC resistance is simply used to measure a change in the resistance over time. Tracking the DC
resistance should start before the unit is first put into service. Perform the following steps and record the value for
future comparison. Resistance measurements should be taken periodically according to use.
Preparation:
Tools: Common hand tools.
Ohmmeter with an accuracy of ± 1% at 50 ohms (or use a resistance bridge).
Use low resistance leads, preferably a short piece of 50 ohm coaxial cable fitted with an appropriate
connector or alligator clips.
Temperature of the load should be stabilized between 20°C to 25°C (68°F to 77°F).
DC Resistance Measurement
WARNING
Never attempt to connect or disconnect RF equipment from the transmission
line while RF power is being applied.
Leaking RF energy is a potential health hazard.
Note: It is recommended that this resistance check be performed each time the load is to be used.
1. Turn off RF power and interlock circuitry before making any disconnections.
2. Disconnect the RF coaxial line.
3. Connect the multimeter test leads across the center and outer conductor of the load resistor. See
4. Record the value of the resistance before the load is put into service. Compare subsequent values with the
latest reading. If the values vary more than 2 ohms this could be an indication of a failing resistive element.
Figure 6
.
11
Page 22
Moduload® RF Load Resistor
Figure 6 Measuring DC Resistance
Coolant
Ethylene glycol is toxic. Do not take internally. Avoid contact with eyes, skin, and
clothing. Avoid breathing vapor. Wash thoroughly after handling.
Use only distilled water or the supplied ethylene glycol as coolant. Do not use tap
water, automotive antifreeze, sealants, or leak stopping material. Use of these
materials will damage the instrument and void all warranties.
WARNING
CAUTION
CAUTION
Operation without sufficient coolant can damage the unit.
Changing Coolant
Note: Follow these instructions to change the coolant.
To just add coolant, go to step 5.
To just drain the coolant, follow steps 1 – 4.
1. Get a clean container, with a capacity of 3 gal. (11 L), to hold the old coolant.
2. Remove the filler cap on top of the heat exchanger.
Note: This will allow the coolant to drain faster.
3. Unscrew and remove the drain plug on the rear of the load. Drain the coolant into the container.
Note: If the coolant has no contaminants it may be reused.
4. Replace the drain plug and screw it tightly into place.
5. Remove the filler cap on top of the heat exchanger.
6. Add about 3 quarts (2.9 L) of coolant.
7. Turn the unit on for a few seconds to draw coolant into the system.
8. Repeat steps 6 and 7 twice more, until the coolant remains steady at or just below the high mark on the level
gauge.
9. Replace the filler cap.
10. Turn the unit on and run it for five minutes to remove any air trapped in the system.
12
Page 23
Maintenance
Flushing the Coolant
Whenever maintenance work has been performed, including resistor repair, or there is a reason to suspect that
contamination has been introduced or dislodged into the coolant, the system should be thoroughly flushed.
Note: If the unit is to remain fully or partially drained for two weeks or more, see
Storage or Shipment" on page 21
.
WARNING
Disconnect from RF power sources and the AC line before any disassembly or service.
Electrical shock hazard.
CAUTION
Incorrect hose connections will reverse coolant flow and could destroy the load.
Normal Coolant Flush
As scheduled maintenance or If the coolant is contaminated, old and needs to be replaced, the system should be
thoroughly flushed.
1. Drain the circulating system as completely as possible.
2. Fill the unit with fresh, clean, distilled water.
3. Run the load with coolant but without RF power applied for a period of five minutes.
4. Drain and discard the water.
5. Repeat the Steps 2 - 4 until the drained liquid is clear.
6. Fill the unit with distilled water and/or approved ethylene glycol mixture per
"Coolant" on page 3
"Preparation for
.
Coolant Flush after Load Replacement
Prior to installing a repaired load or a new load the cooling system needs to be flushed to remove any debris or
containments that may remain when a damaged load is removed.
1. Open the drain plug.
2. Drain and discard the coolant.
3. Close drain plug.
4. Connect a suitable hose from the outlet of the pump to a drain or container to hold the discarded coolant.
5. Connect a second hose from the inlet of the heat exchanger to a source of clean potable water.
6. Open the fill cap.
7. Turn on water source and allow the tank to fill.
8. Replace the fill cap.
9. Leave the water source on and allow the system to flush for 1 to 3 minutes.
10. Turn the water source off.
11. Reverse the position of the hoses.
12. Flush the system with the water flowing in the opposite direction for 1 to 3 minutes.
13. Repeat steps 9 - 12 until there are no signs of debris or contaminants in the water being discharged.
14. Remove the hoses.
15. Reinstall the load.
16. Fill the unit with distilled water and/or approved ethylene glycol mixture per
"Coolant" on page 3
.
13
Page 24
Moduload® RF Load Resistor
Repair
WARNING
Disconnect the unit from all power sources before servicing.
The unit may be energized from multiple sources.
The potential for electric shock exists.
Replacing the Fuse
1. Correct the fuse burnout cause.
2. Use a flat blade screwdriver to lift the tab securing the fuse drawer, above the AC mains connector.
3. Remove the defective fuse.
4. Replace with the same type and rating fuse
Series 115 Vac: 230 Vac
8640 15 amp 8 amp
8640B 15 amp 8 amp
5. Replace the fuse drawer.
Replacing the Interlock Relay
The interlock relay cannot be repaired in the field. To replace it, follow the instructions below for your model.
WARNING
Disconnect the unit from all power sources before servicing.
The unit may be energized from multiple sources.
The potential for electric shock exists.
For Model 864x
Note: The relay is located on the inside of the front panel at the upper right side.
1. Loosen the screw at the top of the relay clamp.
2. Remove the relay cartridge.
3. Line up the center pin on the new relay with the hole in the socket.
4. Rotate until the key-way engages, then push in.
For Model 864xB
Note: The relay is located on the inside of the front panel at the upper right side.
1. Loosen and remove the nut and washers that secure the relay to the panel.
2. Record the color of each wire and the relay terminal to which it connects then remove the wires from the relay.
3. Remove the relay from its mounting screw.
4. Install the replacement relay by reversing Step 2 through Step 4.
14
Page 25
Replacing the Flow Switch (For Units Manufactured BEFORE 3/1/2010)
Note: The coolant flow switch should be inspected every three to six months, depending on the
amount of use. To inspect it:
1. Drain the coolant. See
"Changing Coolant" on page 12
.
2. Remove the top panel
3. Unscrew the collar holding the wired sensor plug in the flow switch body.
Note: Being careful not to lose the spring and sliding valve on the sensor plug stem.
4. Remove the sensor plug.
5. Clean and replace the sensor plug.
6. Reassemble the unit and replace the coolant.
7. Disconnect the wires at the flow switch.
8. Disconnect the hoses from the flow switch, then unscrew the flow switch from the load.
9. Install the new flow switch by reversing this procedure.
Replacing the Pressure Switch (For Units Manufactured AFTER 3/1/2010)
Maintenance
1. Remove the top panel. See
2. Drain the coolant. See
"Removing the Load" on page 16
"Flushing the Coolant" on page 13
.
.
3. Pull the quick disconnect connector from the thermoswitch terminal.
4. Remove the black pressure switch wire from the thermoswitch.
5. Disconnect the red pressure switch wire by gently prying the retaining clips outward while pulling the
connector away from its mating connector.
6. Unscrew the switch from the output plumbing assembly of the load.
Note: Use a ¾ inch wrench on the hex portion of the pressure switch.
7. Apply a thin coating of Teflon based thread sealant to the male threads of the pressure switch.
8. Thread the switch into the output plumbing assembly.
9. Tighten the pressure switch using a ¾ inch wrench.
10. Reconnect the red wire to the front panel via the in-line connector.
11. Reconnect the black wire to the terminal of the thermoswitch.
12. Replace the coolant in the unit as described in the load replacement procedure,
13. Check for leaks by running the unit with the top panel removed.
14. Ensure the interlock circuit is working by checking the resistance between the two terminals of the interlock
terminal strip on the front panel.
Note: Two seconds after the unit is turned on, the relay contact should close providing a low resis-
tance. When the unit is turned off, the resistance should go high.
15. Remove power from the unit.
16. Replace the top panel.
Note: Ensure that the fan power cable is reconnected to the connector on top of the radiator.
17. Replace the screws and the coolant tank cap.
15
Page 26
Moduload® RF Load Resistor
Removing the Load
WARNING
Radiator fins are very sharp. Avoid contact with the radiator fins. Failure to comply
may result in severe cuts and bleeding.
WARNING
Dangerous voltages are present.
Disconnect the unit from all power line and RF power sources before servicing. Do not
disconnect the unit from the RF transmission line while RF power is applied.
Failure to comply may result in severe electrical shock or death.
Model 864x
1. Disconnect the RF line.
2. Drain the coolant (See
3. Remove the screws that secure the top panel.
4. Lift the top panel and disconnect the fan-supply plug located on top of the radiator block.
5. Loosen the hose clamps on both water hose connections to the load.
6. On the inside of the front panel, remove the nuts holding the load to the front panel.
Note: Remove the nuts only. Do not disturb the screws. The screws also secure the outer conductor
assembly to the load. Hold this assembly to keep it from falling and being damaged.
7. Unscrew the mounting clamp holding the load to the rest of the unit. Remove the top half of the clamp.
8. Carefully push the load forward a few inches to access the wires and water connection fittings.
9. Disconnect the flow switch wires from the front panel.
10. Note the position and direction of the flow switch and the output elbow on the load. Unscrew these from the
load.
11. The load can now be removed from the unit.
"Changing Coolant" on page 12
).
Model 864xB
1. Disconnect the RF line.
2. Drain the coolant (See
"Changing Coolant" on page 12
).
3. Remove the screws that secure the top panel.
4. Lift the top panel and disconnect the fan-supply plug located on top of the radiator block (
Figure 9
).
5. Loosen the hose clamps on both water hose connections to the load.
6. Remove the screws that secure the load mounting clamp. Remove the top half of the mounting clamp.
7. Disconnect the flow or pressure switch wires. One at the thermal switch, the other at the in-line connector near
the flow or pressure switch.
8. Disconnect the front panel wires at the connector on top of the radiator.
16
Page 27
Figure 7 Removing the Load (Models BEFORE 3/1/2010)
Maintenance
21
4
1
3 2
Item Description
1 Load mounting clamp screws
2 Flow switch wires
3 Fan-supply connector
4 Front panel connector
Figure 8 Removing the Load (Models AFTER 3/1/2010)
21
4
3
1
Item Description
1 Load mounting clamp screws
2 Pressure switch wires
3 Fan-supply connector
4 Front panel connector
2
17
Page 28
Moduload® RF Load Resistor
9. Record the wire colors and locations then disconnect the pump motor wires from the front panel terminal
block (TB 1) (
Figure 10
).
10. Remove the screws that secure the front panel to the unit then tilt the top of the panel away from the unit and
remove the two water hoses from the load water pipes.
11. Remove the front panel with the load attached.
12. Remove the nuts and lock washers that secure the load to the panel.
13. Remove the socket head cap screws that secure the water chamber to the load then remove the water
chamber.
14. Inspect the water chamber to be sure it is in good condition and that the inner o-ring seal is good. If
appropriate, order replacement parts.
Figure 9 Front Panel Wiring
Removing the Pump
WARNING
Disconnect the unit from all power sources before servicing. The unit may be
energized from multiple sources. The potential for electric shock exists.
1. Drain the coolant (See
2. Remove the load (See
3. Disconnect the pump wire leads from the terminal block on the inside of the front panel.
4. Loosen the hose clamps on the input and output hoses to the pump.
5. Remove the hoses.
6. Loosen the hose clamp on the drain tube at the base of the pump.
7. Remove the drain tube.
8. Unscrew the bolts securing the base of the pump to the unit.
9. Remove the pump, carefully, from the unit.
Note: Note the position and direction of the fittings, then twist them off counterclockwise.
10. To replace the pump, reverse the above steps.
Note: When replacing the threaded fittings, carefully coat the external threads, ONLY, with a pipe
sealing compound. Coating only the external threads reduces the chances of contaminating the coolant.
"Changing Coolant" on page 12
"Removing the Load" on page 16
).
).
18
Page 29
Maintenance
Servicing the Resistor
The load is designed to be quickly and easily repaired in the field. If a significant change in the DC resistance is noted
or if the resistor should fail, inexpensive replacement resistors are available.
WARNING
Disconnect the unit from all power sources before servicing.
The unit may be energized from multiple sources.
The potential for electric shock exists.
Figure 10 Load, Exploded View
Removing the Resistor
Note: Numbers in brackets [ ] refer to the labeled parts in
1. Disconnect the load (see
2. Turn the load on end with the hose fitting up.
3. Use a 316 hex socket wrench to back the cap screws [6] approximately 12 inch.
4. Pull the water chamber assembly out. It may be necessary to rock the chamber gently while pulling.
Note: If the resistor [1] is intact it may be pulled straight out of the load housing and is ready for
replacement. The outer flow tube is captive and will not come out of the housing at this stage.
The ground cap assembly [10] and the inner flow tube [9] should come out with the water chamber assembly. To
remove the ground cap assembly [10], hold the resistor sleeve [7] on the flow tube and pull out the assembly. This
includes the cushioning O-Ring [8] which fits loosely below the stop sleeve; do not lose it.
"Removing the Load" on page 16
).
Figure 10
.
19
Page 30
Moduload® RF Load Resistor
The resistor sleeve [7] has a small escape hole at the side and an access counter bore leading to it. If the sleeve is
removed, be sure this counterbore faces the O-Ring and the resistor [1] during reassembly. This is essential for
internal water venting. The base of the inner flow tube has water outlet holes and a small shoulder. At reassembly,
these must fit into mating recesses in the input fitting.
Inspecting the Resistor
Note: Carefully check the resistor [1] for fractures.
Note: Even in the event of resistor failure the resistor substrate will usually remain intact.
Check the inside of the load housing for damage to the internal parts.
If no damage has been found proceed to “
Replacing the Resistor
”.
If the resistor is broken, other internal parts are damaged, or if the parts do not fit together properly,
proceed to “
Removing a Fractured Resistor
1. Turn the load on end with the RF input connector up to allow any loose pieces of the resistor to fall out of the
housing.
2. Use a 316 hex socket wrench to remove the cap screws [16].
3. Remove the outer conductor assembly [12].
4. Pull out the center conductor assembly [11].
5. Remove any remaining pieces of the resistor carefully.
Note: Normally the outer flow tube will remain with the load housing. If it comes out, return it after
inspection and cleaning.
6. Check the inside of the load housing for damage.
7. Remove the inner flow tube [9] and ground cap assembly [10].
Note: Check them for broken pieces.
8. Under clear running water, thoroughly wash the inside of the conductor assemblies, load housing, and water
chamber.
9. Replace the ground cap assembly and the inner flow tube.
Replacing the Resistor
Removing a Fractured Resistor
”.
1. Insert the new resistor [1] into the resistor fitting of the center conductor assembly [15] to test its tightness.
Note: The resistor should be snug but should not have to be forced into the fitting. If the resistor is too
loose, press the fitting fingers together slightly and try the resistor again. Continue closing the ends of
the resistor fitting until a snug fit is obtained.
2. Bottom the resistor in the fitting.
3. Insert the resistor and the center conductor assembly into the load housing.
4. Replace the outer conductor assembly [12] and screw it into place.
5. Stand the load on its end with the RF connector down.
6. Replace the ground cap assembly onto the exposed end of the resistor. Make sure that it seats on the load
housing.
Note: If the inner flow tube [9] is separated from the water chamber assembly [3], place it inside the
resistor and lower until it reaches the resistor fitting. Gently twist the flow tube until it seats in the bottom of the resistor fitting.
7. Check that the O-Ring [8] is on the inner flow tube next to the resistor and the resistor sleeve [7] is right behind
it.
20
Page 31
Maintenance
8. Ensure the counterbore faces the O-Ring and the resistor.
9. Replace the water chamber [3], gently rocking and twisting the chamber to achieve a flat seat on the outer
housing.
Note: If the water chamber does not fit properly make sure that the inner flow tube is properly
placed.
10. Tighten the water chamber screws [6].
11. Check the DC resistance between the inner and outer conductors; it should be about 50 ohms.
Note: Record this measurement as the new baseline reading.
12. Install the load on the heat exchanger.
13. Connect the hoses and fill with coolant.
14. Run the pump for five minutes and check for leaks before applying RF power.
Replacing the Conductor
1. Use a 316 Allen wrench to remove the cap screws [16] from the RF connector.
2. Remove the outer conductor assembly [12].
Note: If only the outer conductor needs replaced, install it now and screw it into place.
3. Remove the center conductor assembly [11] by pulling it carefully out of the load housing.
4. Ensure the resistor [1] and inner flow tube [9] do not come out with the center conductor.
5. Insert the new center conductor assembly into load housing.
6. Ensure the resistor fitting makes a snug fit with the resistor.
7. Replace the outer conductor and screw it into place.
Preparation for Storage or Shipment
Store the Bird 8640 in a cool, dry area. For pure water-cooled units, the ambient temperature must be within 5°C to
50°C (41°F to 122°F). For units with 35% ethylene glycol, the ambient temperature must be within –25°C to 45°C (–
13°F to 113°F). Drain the coolant (see
days.
To ship, pack the unit in its original shipping container. If this is not available, securely pack and seal it in a sturdy
wooden box or equivalent, with sufficient padding to avoid shock damage.
"Changing Coolant" on page 12
) if the unit will be stored for more than 30
Customer Service
Any maintenance or service procedure beyond the scope of those in this chapter should be referred to a qualified
service center.
If the unit needs to be returned for any reason, request an Return Material Authorization (RMA) through the Bird
Technologies website. All instruments returned must be shipped prepaid and to the attention of the RMA number.
Bird Service Center
30303 Aurora Road
Cleveland (Solon), Ohio 44139-2794
Fax: (440) 248-5426
E-mail: bsc@birdrf.com
For the location of the Sales Office nearest you, visit our Web site at:
http://www.birdrf.com
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Page 32
Moduload® RF Load Resistor
Specifications
Frequency Range
Power Rating
Mode
Impedance
VSWR
Connectors
8645
8646
Interlock Rating
Cooling Method
1
Coolant
Coolant Capacity
AC Power
–115
–230
–230–6
Fuse Rating (864x)
115 Vac
230 Vac
Fuse Rating (864xB)
115 Vac
230 Vac
Ambient Temperature
Water only
35% Ethylene Glycol
Dimensions
Weight, Nominal
1 kHz – 900 MHz
25 kW continuous duty
CW, AM, FM, SSB, TV and certain pulse types
50 ohms nominal
1.10 max
318 inch EIA Flanged
318 inch Unflanged
NO or NC Connections
5A @ 250 Vac
10A @ 125 Vac
48 Vdc
Water dielectric and forced air convection
Distilled water or distilled water/ethylene glycol mixture
9 qts. (8.5 L) nominal
115 VAC @ 11 A, 60 Hz
230 VAC @ 5.5 A, 50 Hz
230 VAC @ 5.5 A, 60 Hz
3AB Time-Delay
15 A
8 A
Time-Delay
15 A (3AB)
8 A (5x20 mm)
2
+5 to +452 °C (41 to 113 °F)
–20 to +352 °C (–4 to +95 °F)
26"L x 19-5/8”W x 19-1/4”H (670 x 500 x 490 mm)
154 lb. (70 kg)
22
1 Below 5°C, ONLY use 35% E.G. and 65% Dist. H2O mixture
2 Above 30°C (86 °F) with water only, or 25°C (77 °F) with a 35% ethylene glycol mixture,
derate power to 20 kW max.
Page 33
Maintenance
Replacement Parts
The parts lists in this section identify the components of the Bird Moduload. Exploded views are used to illustrate
the component parts and indicate their relation to each other. Each part in the exploded view has an item number
referencing the part list.
Load
Item
No.
Load Complete
8645
8646
1 Resistor 1 8755-027
2 Outer O-Ring 1 8410-009
3 Water Chamber 1 8755-014
4 Water Chamber Inner O-Ring 1 5-099
5
Fitting, 90°
5A Fitting, Straight, consisting
of:
6 Screw
7 Resistor Sleeve 1 8755-026
8 Sleeve O-Ring 1 8110-059
9 Inner Flow Tube 1 8755-025
9A Outer Flow Tube 1 8755-024
10 Resistor Ground Cap 1 8755-005
11 Center Conductor Assembly
12 Outer Conductor Assembly
15 Center Conductor O-Ring 1 5-1127
16 Screw
17 Inner O-Ring 1 5-567
Description Qty Part No.
1
8745-101-1
8746-101
BEFORE 3/1/2010
1
8640-089
BEFORE 3/1/2010
1
5-489-1
Bushing
Nipple
1
-20 x 2-
4
8645
8646
8645
8646
1
-20 x 1-
4
1
inch 6 1121-2508-00
2
1
inch 6 1121-1808-00
2
1
5-490-1
1
8755-007
8756-003
1
8755-004
8756-002
AFTER 3/1/2010
8640A089
AFTER 3/1/2010
8645A003
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Page 34
Moduload® RF Load Resistor
Heat Exchanger
Description Qty Part No.
AC Cord
864x-115
864x-230
Fan Assembly (model 864x)
864x-115
864x-230 and 864x-230-6
8646-230-6-N
Fan Assembly (model 864xB)
864xB - 115
864xB - 230 and 864xB - 230-6
Pump (model 864x)
864x-115
864x-230
864x-230-6
Pump (model 864xB)
864xB - 115
864xB - 230
864xB - 230-6
Flow Switch Assy (model 864x) 1 8645-004
Flow Switch Assy (model 864xB) 1 8645B004
Interlock Relay
864x-115
864x-230
864xB series
Pressure Switch
(Replaces Flow Switch in units
AFTER March 2010)
Fuse (model 864x)
864x and 864xB -115
864x - 230
864xB - 230
Fuse (model 864xB)
864xB - 115
864xB - 230
Coolant Gauge Kit 1 5-1200
Ethylene Glycol 1 Gal. 5-1134-3
1
5-1836
5-1837
2
8640-668-1
8640-668-2
8640-668-4
2
5A2770-1
5A2770-2
1
8640A505-1
8640A505-2
8640A505-4
1
8640B505-1
8640B505-2
8640B505-4
1
5-1627
5-1625
5A2787-1
1 8645C004
2
5-1828-36 (15 A 3AB time delay)
5-1828-33 (8 amp 3AB time delay)
5A2257-25 (8 amp 5x20 mm)
2
5-1828-36 (15 A 3AB time delay)
5A2257-25 (8 A 5x20 mm)
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Page 35
Limited Warranty
All products manufactured by Seller are warranted to be free from defects in material and workmanship for a
period of one (1) year, unless otherwise specified, from date of shipment and to conform to applicable specifications, drawings, blueprints and/or samples. Seller’s sole obligation under these warranties shall be to issue credit,
repair or replace any item or part thereof which is proved to be other than as warranted; no allowance shall be
made for any labor charges of Buyer for replacement of parts, adjustment or repairs, or any other work, unless such
charges are authorized in advance by Seller.
If Seller’s products are claimed to be defective in material or workmanship or not to conform to specifications,
drawings, blueprints and/or samples, Seller shall, upon prompt notice thereof, either examine the products where
they are located or issue shipping instructions for return to Seller (transportation charges prepaid by Buyer). In the
event any of our products are proved to be other than as warranted, transportation costs (cheapest way) to and
from Seller’s plant, will be borne by Seller and reimbursement or credit will be made for amounts so expended by
Buyer. Every such claim for breach of these warranties shall be deemed to be waived by Buyer unless made in writing within ten days from the date of discovery of the defect.
The above warranties shall not extend to any products or parts thereof which have been subjected to any misuse or
neglect, damaged by accident, rendered defective by reason of improper installation or by the performance of
repairs or alterations outside of our plant, and shall not apply to any goods or parts thereof furnished by Buyer or
acquired from others at Buyer’s request and/or to Buyer’s specifications. Routine (regularly required) calibration is
not covered under this limited warranty. In addition, Seller’s warranties do not extend to the failure of tubes, transistors, fuses and batteries, or to other equipment and parts manufactured by others except to the extent of the
original manufacturer’s warranty to Seller.
The obligations under the foregoing warranties are limited to the precise terms thereof. These warranties provide
exclusive remedies, expressly in lieu of all other remedies including claims for special or consequential damages.
SELLER NEITHER MAKES NOR ASSUMES ANY OTHER WARRANTY WHATSOEVER, WHETHER EXPRESS, STATUTORY,
OR IMPLIED, INCLUDING WARRANTIES OF MERCHANTABILITY AND FITNESS, AND NO PERSON IS AUTHORIZED TO
ASSUME FOR SELLER ANY OBLIGATION OR LIABILITY NOT STRICTLY IN ACCORDANCE WITH THE FOREGOING.
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