INSTRUCTION BOOK ® MODULOAD RF LOAD RESISTOR SERIES 8640 and 8640B INCLUDING MODELS 8645-xxx AND 8646-xxx Bird® Electronic Corporation 30303 Aurora Road Cleveland (Solon), Ohio 44139 Sales & Technical Support: 440-248-1200 866-695-4569 toll free Sales email: sales@bird-technologies.com Technical Support email: techsupport@bird-technologies.com ©Copyright 2008 by Bird Electronic Corporation Instruction Book Part Number 920-8640S Rev. F ® ® ® ® Moduload , Econoload , Econoline , and Thruline are registered trademarks of Bird Electronic Corporation 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 applied to all phases of operation and maintenance. Keep Away From Live Circuits Operating personnel must at all times observe normal safety regulations. Do not replace components or make adjustments inside the equipment with high voltage turned on. To avoid casualties, always remove power. Shock Hazard Do not remove the RF transmission line while RF power is present. Capacitors can store a dangerous electric charge. Avoid contact with all system capacitors. If it is necessary to perform work near a system capacitor, be sure to discharge the capacitor through a low resistance. Do Not Service Or Adjust Alone Under no circumstances should any personnel 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. 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. Chemical Hazard Dry cleaning solvents for cleaning parts may be potentially dangerous. Avoid inhalation of fumes or prolonged contact with skin. Coolant may contain ethylene glycol. Avoid ingestion, inhaling of vapors and eye and skin contact. Resuscitation Personnel working with or near high voltages should be familiar with modern methods of resuscitation. i Bird 8640 and 8640B Series Moduload RF Load Resistor Safety Symbols 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 follwed. The caution symbol appears on the equipment indicating there is important information in the instruction manual regarding that particular area.  NOTE: Calls attention to supplemental information. 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 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. WARNING Connect the power cord to the Moduload BEFORE connecting to ac mains. WARNING Ethylene glycol is toxic. Do not take internally. Avoid contact with eyes, skin, and clothing. Avoid breathing vapor. Wash thoroughly after handling. ii 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 HEAVY. Do not lift this unit alone. 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 air flow. The air intake vents on the side of the heat exchanger and the exhaust on top must not be obstructed. 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 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 unit and void all warranties. CAUTION Operation without sufficient coolant can damage the unit. iii Bird 8640 and 8640B Series Moduload RF Load Resistor 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. 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. iv 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. 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. v Bird 8640 and 8640B Series Moduload RF Load Resistor About This Manual This manual covers the Bird 8645B and 8646B Moduload RF Load Resistors. This instruction book is arranged so that essential information on safety is in the front of the book. Reading the Safety Precautions before operating the equipment is strongly advised. The remainder of this instruction book is divided into Chapters and Sections. Operation First time operators should read Chapter 1 - Introduction, and Chapter 3 - Installation, to get an overview of equipment capabilities and how to install it. An experienced operator can refer to Chapter 4 - Operating Instructions. All instructions necessary to operate the equipment are contained in this chapter. Maintenance All personnel should be familiar with preventative maintenance found in Chapter 5 - Maintenance. If a failure should occur, the troubleshooting section will aid in isolating and repairing the failure. Parts lists and repair instructions are also in this chapter. Changes To The Manual We have made every effort to ensure this manual is accurate at the time of publication. If you should discover any errors or if you have suggestions for improving this manual, please send your comment to our factory. This manual may be periodically updated. When inquiring about updates to this manual, refer to the part number and revision level on the title page. Naming Conventions The following terms will be used throughout this manual to refer to certain components of the Moduload: 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. vi Resistor: A subcomponent of the LOAD. This is the ceramic resistor which actually absorbs the RF power. vii Table of Contents Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . i About This Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . vi Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Moduload Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Items Supplied . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Items Required but not Supplied. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Optional Items Available . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Theory of Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Resistor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Flow Interlock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Thermal Interlock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Unpacking and Inspection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 DC Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Meter Rack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Interlock Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 AC Mains Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Adding Coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Connecting RF Power. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Operating Instructions . . . . . . . . . . . . . . . . . . . . . . . . . 11 Normal Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Emergency Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 viii Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 DC Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Changing Coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Coolant Flush . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Fuse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Interlock Relay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Flow Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Load Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Pump Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Resistor Servicing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Resistor Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Fractured Resistor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Resistor Replacement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Conductor Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Preparation for Storage or Shipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Customer Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Replacement Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Heat Exchanger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 ix x 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 y Useable with CW, AM, FM, SSB, and TV modulation, and certain Features pulse types. Contact Bird Electronic Corporation for information on using Moduloads with pulsed signals. y Useable to make RF power measurements when used with a Bird 4600 or 4800 Thruline Wattmeter y Self-contained water-based cooling system y Time-delay interlock ensures steady coolant flow before RF power is applied Indicators y Coolant Level Gauge Items Supplied y Moduload y Instruction Manual y Power Meter Rack-Mount Kit Items Required but y No. 22 AWG wire, with ring terminals, for interlock connection not Supplied y RF Coupling Kit y Ethylene Glycol, Industrial Grade, 1 Gallon - available from Bird Optional Items y Dolly (Bird P/N 6771-011) for moving the load Available 1 Bird 8640 Series Moduload RF Load Resistor Figure 1 8640 Series Moduload Outline Drawing 19.25” (490 mm) AC ON 9.75” INTERLOCK (248 mm) 26” 9.875” (660 mm) (251 mm) 19.625” (500 mm) Coolant Figure 2 Reservoir System Block Diagram Temperature Flow Switch Pump Switch RF Input Load Resistor Fan Heat Exchanger Fan Heat Exchanger 2 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 opens causing immediate transmitter shutdown. The flow switch is a “normally open” type, and is closed during normal operation. After flow is restored, a time delay switch 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 Bird 8640 Series Moduload RF Load Resistor 4 Chapter 3 Installation This chapter provides information on site requirements, unpacking, inspection, and preparing the Bird 8640 Moduload for use. Unpacking and 1. Carefully inspect the shipping container for signs of damage. If Inspection damage is noticed, do not unpack the unit. Immediately notify the shipping carrier and Bird Electronic Corporation. 2. If the container is not damaged, unpack the unit. Save the packing materials in case the unit should need to be shipped again. 3. Inspect all of the components for visible signs of damage. Immediately notify the shipping carrier and Bird Electronic Corporation of equipment damage or missing parts. 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. y Do not use outdoors or in areas of condensing humidity. y Surrounding air must be free of contaminants or particles that could be drawn into the air intakes. y The heat exchanger must be operated in a horizontal position. y AC power is required. y Allow a minimum of one foot clearance along the sides and three feet over the top to allow unobstructed air intake and exhaust. y 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 1 a screw with a ⁄ inch (6.4 mm) diameter max. The brackets may be 4 removed by removing the screws holding them to the Moduload. 5 Bird 8640 Series Moduload RF Load Resistor DC Resistance Before first using the load, get a resistance baseline for future maintenance. Refer to “DC Resistance” on page 14 for instructions. 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 1 supplied #6-32 x ⁄ screws to assemble the rack. To install the rack, 4 remove two screws from the Moduload where the rack will be 3 mounted, then screw it into place with the supplied #8-32 x ⁄ screws. 8 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 CAUTION Connection Do not operate without the interlock. Even momentary application of RF power while coolant is not circulating could cause immediate destruction of the load. y Use number 22 AWG (or heavier) wire for interlock connection. Attach solderless ring terminals to the wire for ease of installation. y 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 CAUTION Connection 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, 1φ. The unit is equipped with an IEC 320 “cold” (70 °C) ac inlet. 6 Installation 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 glycol, to ensure proper mixing. Figure 3 on page 8 shows the coolant’s freezing point for a given percentage of ethylene glycol in the mix. The following example shows the weights to make a 65% distilled water to 35% ethylene glycol mixture in 5 and 55 gallon quantities. 5 Gal. (18.9 L) 55 Gal. (208.2 L) Distilled Water 28.0 lb (12.7 kg) 310 lb (140.6 kg) Ethylene Glycol 15.2 lb (6.9 kg) 167 lb (75.7 kg) 7 Bird 8640 Series Moduload RF Load Resistor 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. Make sure 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 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. Figure 3 0 Freezing Point of Ethylene Glycol / Distilled Water -10 Mixture -20 -30 -40 Specifications for ethylene glycol -50 having: specific gravity 1.125 @ 32°F; specific heat .575 @ 68°F -60 10 20 30 40 50 60 % Ethylene Glycol 8 Temperature, Degrees Celsius Installation 40 20 0 -20 -40 Specifications for ethylene glycol -60 having: specific gravity 1.125 @ 32°F; specific heat .575 @ 68°F -80 10 20 30 40 50 60 % Ethylene Glycol 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 while following the instructions below: Figure 4 RF COAXIAL LINE BOLT BULLET LOAD Swivel Flanged Coupling 9 Temperature, Degrees Fahrenheit Bird 8640 Series Moduload RF Load Resistor y Insert the center bullet and push it in until it is fully seated. y 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. y 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 while following the instructions below: Figure 5 RF COAXIAL CLAMPING CONNECTOR BULLET LOAD LINE BANDS SLEEVE Unflanged Coupling y Insert the center bullet and bottom it on the midpoint nibs. y Position the outer sleeve, with clamping bands, over the input connector. y Set the transmission line snugly against the coupling stops. y Position the clamping bands evenly about 3/4” from the ends of the sleeve. y Tighten the clamping bands. 10 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 y Check that the coolant level is above the min. mark on the gauge. y Turn on the Moduload. y Check that the fans are running properly. y Wait about 2 seconds for proper coolant flow and for the interlock to close. y Apply RF power. Shutdown y Turn off RF power at the source. y Wait five minutes for the system to cool to room temperature. y Turn off the Moduload. Emergency Turn off RF power at the source. Shutdown If the interlock is properly connected, RF power will be automatically turned off if a fault occurs in the Moduload. 11 Bird 8640 Series Moduload RF Load Resistor 12 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 No ac power Connected the unit to ac mains operating Unit turned off Set the line switch to ON Fuse burnout Replace fuse after correcting the burnout cause (See “Fuse” on page 16) Coolant leaking Loose connections Tighten drain plug and all connections Worn or cracked hose Replace defective hose Interlock opening Insufficient coolant flow Check coolant level. Add coolant if necessary repeatedly (see “Changing Coolant” on page 15). Defective flow switch Check flow switch (see “Flow Switch” on page 17). RF power too high Lower RF power Ambient temperature too Lower ambient temperature high Air intakes or exhaust are Check that clearances are at least blocked 1 foot on the sides and 3 feet on top Clean panels (See “Cleaning” on page 14) Excessive reflected DC resistance of the load Check dc resistance (See “DC Resistance” on power has changed page 14) 13 Bird 8640 Series Moduload RF Load Resistor 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. 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: y Remove the screws around the edge of the top panel. y Lift the top panel to access the fan power connector then disconnect the fan cable. y Remove the top panel. Inspection 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 15. DC Resistance Measuring the dc resistance between the inner and outer conductors of the RF connector shows changes in the load over time, a good check of the resistor’s condition. Under normal operating conditions, the resistor should provide at least 5,000 hours of operation before requiring any additional service. DC resistance tracking must start before the load is put into service, and should be measured annually. Perform the following steps and record the value for future comparison. Make sure that you have an ohmmeter with an accuracy of ±1% at 50 ohms and that the load temperature is between 20 and 25 °C (68 to 77 °F) before starting. 14 Maintenance Figure 6 Measuring Resistance 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. y Turn off the RF power and interlock circuitry. y Disconnect the RF line. y Connect the multimeter test leads to the center and outer conductor of the load. Refer to Figure 6. y Compare the measured value with the previous measurement and with the baseline resistance, measured when the load was put into service. If the new value differs from either of these by more than 2 ohms this could indicate a failing 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 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. CAUTION Operation without sufficient coolant can damage the unit. Changing Coolant Follow these instructions to change the coolant. To just add coolant, go to step 5. To just drain the coolant, follow steps 1 – 4. 15 Bird 8640 Series Moduload RF Load Resistor 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. 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 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. Coolant Flush If the coolant is contaminated, for example by pipe sealant or a broken resistor, the system should be thoroughly flushed. To do this: 1. Fill the unit with clean, potable water. 2. Run the unit for five minutes with no RF power applied. 3. Drain the coolant and discard it. 4. Repeat steps 1 – 3 until the drained liquid is clear. 5. Refill the system with proper coolant (distilled water or a distilled water/ethylene glycol mixture) as described above. 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. 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. 16 Maintenance 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. 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. Model 864x 1. The relay is located on the inside of the front panel at the upper right side. 2. Loosen the screw at the top of the relay clamp. 3. Remove the relay cartridge. 4. Line up the center pin on the new relay with the hole in the socket, rotate until the keyway engages, then push in. Model 864xB 1. The relay is located on the inside of the front panel at the upper right side. 2. Loosen and remove the nut and washers that secure the relay to the panel. 3. Record the color of each wire and the relay terminal to which it connects then remove the wires from the relay. 4. Remove the relay from its mounting screw. 5. Install the replacement relay by reversing Step 2 through Step 4. Flow Switch The coolant flow switch should be inspected every three to six months, depending on the amount of use. To inspect it: 17 Bird 8640 Series Moduload RF Load Resistor 1. Drain the coolant (see “Changing Coolant” on page 15). 2. Remove the top panel 3. Unscrew the collar holding the wired sensor plug in the flow switch body. 4. Being careful not to lose the spring and sliding valve on the sensor plug stem, remove the sensor plug. 5. Clean and replace the sensor plug. 6. Reassemble the unit and replace the coolant. To replace the flow switch: 1. Disconnect the wires at the flow switch. 2. Disconnect the hoses from the flow switch, then unscrew the flow switch from the load. Load Removal 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 “Changing Coolant” on page 15). 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. 18 Maintenance  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. Model 864xB 1. Disconnect the RF line. 2. Drain the coolant (see “Changing Coolant” on page 15). 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 7). 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 switch wires. One at the flow switch, the other at the in-line connector near the flow switch. 8. Disconnect the front panel wires at the connector on top of the radiator. 19 OUT Bird 8640 Series Moduload RF Load Resistor Figure 7 1 2 Removing the Load 2 4 3 1 Item Description 1 Load mounting clamp screws 2 Flow switch wires 3 Fan-supply connector 4 Front panel connector 20 E IN AL RM E R IN Maintenance 9. Record the wire colors and locations then disconnect the pump motor wires from the front panel terminal block (TB 1) (Figure 8). 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 8 Front Panel Wiring ORG GRN / YEL BLK WHT RED YEL BLK BLK WHT GRN / YEL BLK WHT BLK WHT GRN / YEL 21 Bird 8640 Series Moduload RF Load Resistor Pump Removal 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 “Changing Coolant” on page 15). 2. Remove the load (see “Load Removal” on page 18). 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, and remove the hoses. 5. Loosen the hose clamp on the drain tube at the base of the pump. Remove the drain tube. 6. Unscrew the bolts securing the base of the pump to the unit. 7. Carefully remove the pump from the unit. 8. Note the position and direction of the fittings, then twist them off counterclockwise. 9. To replace the pump, reverse the above steps. 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. 22 Maintenance Resistor Servicing 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 9 Load Exploded View 5A 6 Hose Fitting Straight 12 1/4-20 x 2-1/2 Socket Head Cap Screw (6) Outer Conductor Assembly 5 Hose Fitting 90° 16 3 4 1/4-20 x 1-1/2 and Socket Head Cap Screw (6) Water Chamber With O-Ring Inner Seal 11 10 Center Conductor Ground Cap Assembly Assembly 2 Outer O-Ring 15 Resistor Fitting Seal O-Ring 9 17 Inner Flow Tube Inner O-Ring 7 Resistor Sleeve 1 Resistor 8 O-Ring 1 Resistor Load Housing 9A Load Housing Outer Flow Tube Resistor Removal Numbers in brackets [ ] refer to the labeled parts in Figure 9. 1. Disconnect the load (see “Load Removal” on page 18). 2. Turn the load on end with the hose fitting up. 23 Bird 8640 Series Moduload RF Load Resistor 3 3. Use a ⁄ hex socket wrench to back the cap screws [6] 16 1 approximately ⁄ inch. 2 4. Pull the water chamber assembly out. It may be necessary to rock the chamber gently while pulling. 5. 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. 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. Inspection y Carefully check the resistor [1] for fractures.  NOTE: Even in the event of resistor failure the resistor substrate will usually remain intact. y Check the inside of the load housing for damage to the internal parts. If no damage has been found proceed to “Resistor Replacement”. However, if the resistor is broken, other internal parts are damaged, or if the parts do not fit together properly, proceed to “Fractured Resistor”. 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. 3 2. Use a ⁄ hex socket wrench to remove the cap screws [16]. 16 3. Remove the outer conductor assembly [12]. 4. Pull out the center conductor assembly [11]. Carefully remove any remaining pieces of the resistor. Normally the outer flow tube will remain with the load housing. If it comes out, return it after inspection and cleaning. 5. Check the inside of the load housing for damage. 24 Maintenance 6. Remove the inner flow tube [9] and ground cap assembly [10]. Check them for broken pieces. 7. Under clear running water, thoroughly wash the inside of the conductor assemblies, load housing, and water chamber. 8. Replace the ground cap assembly and the inner flow tube. Resistor 1. Insert the new resistor [1] into the resistor fitting of the center Replacement conductor assembly [15] to test its tightness. 2. 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. 3. Bottom the resistor in the fitting. 4. Insert the resistor and the center conductor assembly into the load housing. 5. Replace the outer conductor assembly [12] and screw it into place. 6. Stand the load on its end with the RF connector down. 7. Replace the ground cap assembly onto the exposed end of the resistor. Make sure that it seats on the load housing. 8. 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. 9. 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. Make sure the counterbore faces the O-Ring and the resistor. 10. 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. 11. Tighten the water chamber screws [6]. 12. Check the dc resistance between the inner and outer conductors; it should be about 50 ohms. Record this measurement as the new baseline reading. 13. Install the load on the heat exchanger. Connect the hoses and fill with coolant. 25 Bird 8640 Series Moduload RF Load Resistor 14. Run the pump for five minutes and check for leaks before applying RF power. 3 Conductor 1. Use a ⁄ allen wrench to remove the cap screws [16] from the RF 16 Replacement 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. Make sure the resistor [1] and inner flow tube [9] do not come out with the center conductor. 4. Insert the new center conductor assembly into load housing. Make sure the resistor fitting makes a snug fit with the resistor. 5. Replace the outer conductor and screw it into place. 26 Maintenance 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 “Changing Coolant” on page 15) if the unit will be stored for more than 30 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. Customer Service Any maintenance or service procedure beyond the scope of those in this chapter should be referred to a qualified service center. If you need to return the unit for any reason, contact the Bird Service Center for a return authorization. All instruments returned must be shipped prepaid and to the attention of Bird Service Center. Bird Service Center 30303 Aurora Road Cleveland (Solon), OH 44139-2794 Phone: (440) 519-2298 Fax: (440) 519-2326 E-mail: bsc@bird-technologies.com For the location of the Sales Office nearest you, give us a call or visit our Web site at: http://www.bird-electronic.com 27 Bird 8640 Series Moduload RF Load Resistor Specifications 1 kHz – 900 MHz Frequency Range 25 kW continuous duty Power Rating CW, AM, FM, SSB, TV and certain pulse types Mode 50 ohms nominal Impedance 1.10 max VSWR Connectors 1 8645 3 ⁄ inch EIA Flanged 8 1 8646 3 ⁄ inch Unflanged 8 NO or NC Connections Interlock Rating 5A @ 250 Vac 10A @ 125 Vac 48 Vdc Water dielectric and forced air convection Cooling Method * Distilled water or distilled water/ethylene glycol Coolant mixture 9 qts. (8.5 L) nominal Coolant Capacity AC Power –115 115 Vac @ 11 A, 60 Hz –230 230 Vac @ 5.5 A, 50 Hz –230–6 230 Vac @ 5.5 A, 60 Hz 3AB Time-Delay Fuse Rating (864x) 115 Vac 15 A 230 Vac 8 A Time-Delay Fuse Rating (864xB) 15 A (3AB) 115 Vac 8 A (5x20 mm) 230 Vac † Ambient Temperature † Water only +5 to +45 °C (41 to 113 °F) † 35% Ethylene Glycol –20 to +35 °C (–4 to +95 °F) 26"L x 19-5/8"W x 19-1/4"H (670 x 500 x 490 mm) Dimensions 154 lb. (70 kg) Weight, Nominal * Below 5°C, ONLY use 35% E.G. and 65% Dist. H O 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. 28 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. Figure 10 Load Exploded View 5A 6 Hose Fitting Straight 12 1/4-20 x 2-1/2 Socket Head Cap Screw (6) Outer Conductor Assembly 5 Hose Fitting 90° 16 4 3 and 1/4-20 x 1-1/2 Socket Head Cap Screw (6) Water Chamber With O-Ring Inner Seal 11 10 Center Conductor Ground Cap Assembly Assembly 2 Outer O-Ring 15 Resistor Fitting Seal O-Ring 9 17 Inner Flow Tube Inner O-Ring 7 Resistor Sleeve 1 Resistor 8 O-Ring 1 Resistor Load Housing 9A Load Housing Outer Flow Tube 29 Bird 8640 Series Moduload RF Load Resistor Load ITEM DESCRIPTION QTY PART NO. NO. Load Complete 1 8645 8745-101-1 8646 8746-101 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° 1 8640-089 5A Fitting, Straight, consisting of: Bushing 1 5-489-1 Nipple 1 5-490-1 1 1 6 Screw ⁄ -20 x 2- ⁄ inch 6 1121-2508-00 4 2 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 1 8645 8755-007 8646 8756-003 12 Outer Conductor Assembly 1 8645 8755-004 8646 8756-002 15 Center Conductor O-Ring 1 5-1127 1 1 16 Screw ⁄ -20 x 1- ⁄ inch 6 1121-1808-00 4 2 17 Inner O-Ring 1 5-567 30 Maintenance Heat Exchanger DESCRIPTION QTY PART NO. AC Cord 1 864x-115 5-1836 864x-230 5-1837 Fan Assembly (model 864x) 2 864x-115 8640-668-1 864x-230 and 864x-230-6 8640-668-2 8646-230-6-N 8640-668-4 Fan Assembly (model 864xB) 2 864xB - 115 5A2770-1 864xB - 230 and 864xB - 5A2770-2 230-6 Pump (model 864x) 1 864x-115 8640A505-1 864x-230 8640A505-2 864x-230-6 8640A505-4 Pump (model 864xB) 1 864xB - 115 8640B505-1 864xB - 230 8640B505-2 864xB - 230-6 8640B505-4 Flow Switch Assy (model 864x) 1 8645-004 Flow Switch Assy (model 864xB) 1 8645B004 Interlock Relay 1 864x-115 5-1627 864x-230 5-1625 864xB series 5A2787-1 Fuse (model 864x) 2 864x and 864xB -115 5-1828-36 (15 A 3AB time delay) 864x - 230 5-1828-33 (8 amp 3AB time delay) 864xB - 230 5A2257-25 (8 amp 5x20 mm) Fuse (model 864xB) 2 864xB - 115 5-1828-36 (15 A 3AB time delay) 864xB - 230 5A2257-25 (8 A 5x20 mm) Coolant Gauge Kit 1 5-1200 Ethylene Glycol 1 5-1134-3 Gal. 31 Bird 8640 Series Moduload RF Load Resistor 32 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 (10) 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 WHAT- SOEVER, 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.