BIRD Termaline 8930 Series User manual

Termaline®Load Resistor
Series 8930
Operation Manual
©Copyright 2016 by Bird Technologies, Inc.
Instruction Book Part Number 920-8930S Rev. E
Termaline®is a Registered Trademark
of Bird Electronic Corporation

i
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.

Safety Precautions
ii
Safety Symbols
Note: Calls attention to supplemental information.
WARNING
Warning notes call attention to a procedure which, if not correctly performed, could result
in personal injury.
CAUTION
Caution notes call attention to a procedure which, if not correctly performed, could result
in damage to the instrument.
This symbol indicates that a shock hazard exists if the precautions in the
instruction manual are not followed.
The caution symbol appears on the equipment indicating there is
important information in the instruction manual regarding that particular
area. See page 10 for specific cautions.
This symbol indicates that the unit radiates heat and should not be
touched while hot.

Termaline® Load Resistor
iii
Warning Statements
The following safety warnings appear in the text where there is danger to operating and maintenance personnel
and are repeated here for emphasis.
WARNING
The vent plug must be used at all times when the unit is operating or cooling. Failure to do
so could result in an explosion or severe burns.
WARNING
Turn off ac power and RF power when attaching the power cable.
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.
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
Do not operate with side panel removed. Doing so could result in personal injury.

Caution Statements
iv
Caution Statements
The following equipment cautions appear in the text whenever the equipment is in danger of damage and are
repeated here for emphasis.
CAUTION
Do not block airflow. The air intake vent on the bottom of the load must not be obstructed.
CAUTION
This load is designed for operation in a horizontal position only, with the vent plug up. Do
not use in any other manner.
CAUTION
If installed, connect optional interlock before applying RF power.
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
Maximum power is 2,500 W when the blower is not running. If the indicator light should
turn off, immediately reduce RF power to less than 2,500 W.
CAUTION
Use only Bird coolant, P/N 5-1070, to prevent damage to the load.

Termaline® Load Resistor
v
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.

Safety Statements
vi
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 DESCARGÉAS ELCTRICAS, 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.

Termaline® Load Resistor
vii
CONNECT INTERLOCK TO TRANSMITTER/GENERATOR/AMPLIFIER BEFORE OPERATING.
BRANCHER LE VERROUILLAGE À L’ÉMETTEUR/GÉNÉRATEUR/AMPLIFICATEUR AVANT EMPLOI.
CONECTE EL INTERBLOQUEO AL TRANSMISOR/GENERADOR/AMPLIFICADOR ANTES DE LA
OPERACION.
VOR INBETRIEBNAHME VERRIEGELUNG AM SENDER/GENERATOR/VERSTÄRKER
ANSCHLIESSEN.
PRIMA DI METTERE IN FUNZIONE L’APPARECCHIO, COLLEGARE IL DISPOSITIVO DI BLOCCO AL
TRASMETTITORE/GENERATORE/AMPLIFICATORE.

About This Manual
viii
About This Manual
This manual covers the models listed below:
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.
Chapter Layout
Introduction — Describes the features of the Bird Termaline RF Load Resistor lists equipment supplied and
optional equipment, and provides power-up instructions.
Theory of Operation — Describes how the Termaline RF Load Resistor works and its functions.
Installation — Describes the how to install the Termaline RF Load Resistor.
Operation with Blower — Describes procedures require for operating the load resistor equipped with a blower
unit.
Maintenance — Lists routine maintenance tasks as well as troubleshooting for common problems. Specifications
and parts information are also included.
Connector 115 VAC 230 VAC
Female LC 8931-115 8931-230
1-5/8" EIA Flanged 8932-115 8932-230
3-1/8" EIA Flanged 8936-115 8936-230
3-1/8" Unflanged, Flush Center 8937-115 8937-230
3-1/8" Unflanged, Recessed
Center
8938-115 8938-230

ix
Table of Contents
Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .i
Warning Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .iii
Caution Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .iv
Safety Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
About This Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .viii
Changes to this Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii
Chapter Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii
Chapter 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Items Supplied . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Items Required but not Supplied . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Optional Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Chapter 2 Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Load Resistor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Fans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Power Rating Reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Thermal Interlock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Chapter 3 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Unpacking and Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Thermoswitch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Interlock Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
AC Power Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Connecting RF Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Swivel Flanged Coupling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Unflanged Coupling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Chapter 4 Operating Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Blower Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Normal Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Operation Under Abnormal Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Emergency Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Chapter 5 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
RF Assembly Resistance Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
RF Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Load Resistor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Indicator Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

Table of Contents
x
Fuse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Fans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Storage and Shipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Customer Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Replacement Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Available “QC” Type Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Limited Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

1
Chapter 1 Introduction
Bird 8930 Series Loads are general purpose, 50 ohm, coaxial RF transmission line terminations, useful as standby
reject loads for single or double sideband transmitters. They provide accurate, dependable, and low reflection line
terminations over a frequency range of DC – 1000 MHz. Up to 10,000 watts can be dissipated.
The loads have a coolant chamber surrounded by radiator fins. The front and rear fins form mounting flanges which
can be used as supports for freestanding use or as brackets for fixed mounting. A vent plug at the top of the unit
relieves internal pressure from coolant expansion. A blower with three axial fans is on the bottom of the load. The
load’s simple and rugged design minimizes maintenance requirements.
Items Supplied
Load Resistor: Pre-filled with coolant at the factory
Detachable 3-wire power cable (without male plug for 230 VAC power cable)
One Shipping Plug
One Vent Plug
Instruction Manual
Items Required but not Supplied
Coupling Kit: Connects the load to the RF line
Male plug for the power cable (230 VAC only)
Optional Accessories
Interlock Thermoswitch: Automatically shuts off the transmitter to prevent overheating of the load
Figure 1 Bird 8930 Series Outline Drawing

2
Chapter 2 Theory of Operation
Load Resistor
Bird 8930 Loads consist of a thin-film-on-ceramic resistor immersed in a dielectric coolant. The resistor, individually
selected for its accuracy, is enclosed in a special housing. When surrounded by the coolant, this produces a uniform,
practically reflection-less line termination over the specified frequencies.
Coolant
The load is cooled by forced air and natural fluid convection currents. The coolant, chosen for its desirable dielectric
and thermal characteristics, carries heat from the resistor to the walls of the cooling tank, where radiator fins
surrounding the tank transfer the heat to the forced air flow.
When the coolant is heated, thermal expansion causes an increase in the internal pressure. A vent plug relieves this
pressure while protecting the opening from dirt or other contaminants.
Fans
Forced airflow is provided by three axial fans beneath the heat exchanger. Baffles direct the air over the radiator
fins for more efficient cooling. A passive, normally open control thermoswitch closes when the coolant reaches 60
°C (140 °F), turning the fans on.
Power Rating Reduction
The baffles interfere with the free flow of normal air currents, causing a 75% reduction in heat transfer efficiency if
the forced airflow is stopped. The maximum power dissipation when the fans are not functioning is 2.5 kW.
Thermal Interlock
When installed, a passive, normally closed over-temperature thermoswitch opens above the maximum safe load
temperature of 226 °C (439 °F), turning off transmitter power. The interlock will not permit use of the transmitter
until the load has reached a safe temperature.

3
Chapter 3 Installation
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.
Mounting
Place the load in a dry, dust and vibration free environment. Do not use outdoors or in areas of condensing
humidity. Allow at least 15" (40 cm) of clearance on all sides of the load, or mount it over a suitably reinforced
opening measuring 26"L x 7"W x 5"D (660 x 178 x 127 mm).
Bird 8930 Loads are intended for stationary or fixed use. The mounting brackets on front and rear faces have four
mounting holes arranged in a 7" x 272332" (114.3 x 526.3 mm) rectangle. Use a screw with a 38" (9.5 mm) diameter
max.
Setup
Before first using the load, get a resistance baseline for future maintenance. Refer to "RF Assembly
Resistance Test" on page 11 for instructions.
Remove the shipping plug from the load and replace it with the vent plug. Refer to Figure 1 for images of
the plugs.
CAUTION
Do not block airflow. The air intake vent on the bottom of the load must not be
obstructed.
CAUTION
This load is designed for operation in a horizontal position only, with the vent plug up.
Do not use in any other manner.
WARNING
The vent plug must be used at all times when the unit is
operating or cooling. Failure to do so could result in an
explosion or severe burns.

Installation
4
Thermoswitch
Bird 8930 Loads can be equipped with an optional interlock thermoswitch, P/N 8890-017. It is normally closed,
opening at 226 °C (439 °F), with a rating of 10A @ 120Vac and 5A @ 230Vac.
A control thermoswitch, P/N 8892-333, is used to control the blower assembly. It is normally open, closing at 60 °C
(140 °F), with a rating of 10A @ 120Vac and 5A @ 230Vac.
To install or replace a thermoswitch, follow these instructions:
1. Replace the vent plug with the shipping plug.
2. Interlock Thermoswitch: Supporting the load to prevent damage to the RF connector, stand the unit on its front
with the connector down. In this position there is no danger of coolant spillage.
3. Control Thermoswitch: Stand the unit on its back end, with the connector up. In this position there is no danger
of coolant spillage.
4. Remove the socket plug (or old thermoswitch), using a 916" hex wrench.
5. Insert the new thermoswitch. Sparingly apply pipe sealing compound to the external threads, only, of the
thermoswitch. Do not contaminate the coolant with pipe sealant.
6. Check for coolant leaks upon completion.
WARNING
The vent plug must be used at all times when the unit is
operating or cooling. Failure to do so could result in an
explosion or severe burns.

Termaline® Load Resistor
5
Interlock Connection
If installed, connect the optional interlock thermoswitch to the interlock as follows (see Figure 2 ):
1. Unscrew the larger knurled ring-nut (A) at the lower end of the coupling jack assembly. Pull it off the
thermoswitch jack (B). Unscrew the small knurled cover fitting (C) from the base plug (D) of the connector to
release the base.
2. Thread the interlock wires through the clamp (E) with the washers (F) inside and with its threaded fitting in
place. Service the interlock wires with short tips and put spaghetti sleeves over the wire ends if necessary.
3. Securely solder the interlock leads to the lugs (G) of the connector base.
Note: The ring-nut (A) must be in place over the base plug (D) with the knurled end facing out.
4. Screw on the cover fitting (C), then fasten the cable clamp (E) in place and tighten both yoke screws (H).
5. Put the plug back on the thermoswitch and tighten the nut (A).
Figure 2 Thermoswitch Connections
CAUTION
If installed, connect optional interlock before applying RF power.

Installation
6
AC Power Connection
The AC power supply required for this unit is 115/230 V, depending on the model, @ 50/60 Hz, 1. The blower is
equipped with an IEC 320 “cold” (65C) AC inlet.
Connecting RF Power
After installing the load, the RF transmission line can be attached using standard coaxial line coupling kits.
“QC” Connector Coupling — Use 50 ohm coaxial cable such as
RG-218/U or -220/U (-17A or -19A), appropriate for the frequency and power level of operation. Use a cable
connector which will mate with the one on the load.
Swivel Flanged Coupling
To couple the swivel flange with a flanged RF transmission line, use an appropriate coupling kit. Refer to Figure 3
while following the instructions below:
Figure 3 Swivel Flanged Coupling
Insert the center bullet and push it in until it is fully seated.
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.
Insert the bolt sets and tighten evenly all around to transmission line manufacturer’s recommended
torque. Use all of the bolts.
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
Turn off ac power and RF power when attaching the power cable.
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.
   

Termaline® Load Resistor
7
Unflanged Coupling
To couple the unflanged connector with an unflanged RF line, use an appropriate coupling kit. Refer to Figure 4
while following the instructions below:
Figure 4 Unflanged Coupling
Insert the center bullet and bottom it on the midpoint nibs.
Position the outer sleeve, with clamping bands, over the input connector.
Set the transmission line snugly against the coupling stops.
Position the clamping bands evenly about 3/4” from the ends of the sleeve.
Tighten the clamping bands.








8
Chapter 4 Operating Instructions
Blower Controls
Bird 8930 Loads are equipped with a control switch and indicator light on the front of the blower, underneath the
RF connector. The switch is labeled “MANUAL/AUTOMATIC”. When the switch is set to MANUAL, the fans will run
continuously. When set to AUTOMATIC, the fans will be turned on when the coolant reaches a preset temperature.
The indicator light, labeled “AC ON”, will turn on whenever the unit is connected to ac power.
Normal Operation
Check that the indicator light is on.
Set the switch to MANUAL momentarily to check that the fans are working properly, then set the switch
back to AUTOMATIC.
Apply RF power.
Operation Under Abnormal Conditions
If the indicator light turns off or the fans stop unexpectedly, immediately turn off RF power or reduce it to less than
2,500 W. Refer to "Troubleshooting" on page 9 to correct the problem. A properly connected interlock will prevent
overload.
The load can be subjected to higher power levels for short intervals. If this is likely, make sure the interlock is
properly connected to prevent damage to the load.
Shutdown
Turn off RF power at the source.
Wait approximately 15 minutes, or for the fans to stop running. This will allow the load to cool without
causing heat stress.
Turn off the blower.
Emergency Shutdown
Turn off RF power at the source.
If the interlock thermoswitch is properly connected, RF power will be automatically turned off when the coolant
temperature reaches an unsafe level.
CAUTION
Maximum power is 2,500 W when the blower is not running. If the indicator light
should turn off, immediately reduce RF power to less than 2,500 W.
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.

9
Chapter 5 Maintenance
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
No air flow from blowers;
“BLOWER ON” light off
Unplugged power cable Connect the power cable
No ac power Make sure ac power is properly connected and
turned on
Fuse burnout Replace fuse after correcting the burnout cause (See
"Fuse" on page 14 )
No air flow from blowers;
“BLOWER ON” light on
Fan obstructed by bent grill Straighten the grill
Fan motors overheated Clean the grill and fan blades
(See "Cleaning" on page 10 )
Fan motors burnt out Replace fan ( "Fans" on page 15 )
Air flow from blowers;
“BLOWER ON” light off Lamp burnout Replace lamp (See "Indicator Light" on page 13 )
Leaking coolant
Loose clamping band Tighten the clamping band
Defective or improperly installed
O-ring
Replace the O-ring
(See "Load Resistor" on page 13 )
High or low DC resistance
Loose RF input connector Tighten connector
Faulty RF input connector
Model 8931: Replace connector
(See "RF Connector" on page 13 )
All other models: Return the unit for service
Faulty resistor Replace the resistor
(See "Load Resistor" on page 13 )
Overheating radiator
RF power too high Lower RF power (See
"Specifications" on page 17
for maximum RF po wer)
Coolant level too low Check the coolant level. Add coolant if necessary
(See "Coolant" on page 12 )
Coolant degraded Replace coolant (See "Coolant" on page 12 )
Faulty control thermoswitch Replace control thermoswitch
(See "Thermoswitch" on page 4 )
Faulty resistor Replace the load resistor
(See "Load Resistor" on page 13 )
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
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.