Bendix King KR 87 ADF Maintenance Manual – KI 227 KI 228 Indicator Repair Guide PDF

Description

Bendix King KR 87 ADF Maintenance Manual

This is the complete maintenance and overhaul manual for the Bendix/King KR 87 Automatic Direction Finder system, covering the KR 87 receiver along with the KI 227 and KI 228 ADF indicators and the KA 44 and KA 44B ADF antennas. Published by AlliedSignal Electronic and Avionics Systems under manual number 006-05184-0007, Revision 7, July 1998. Whether you are bench-testing a receiver, aligning a phase detector, or diagnosing a bearing pointer fault, this Bendix King KR 87 ADF maintenance manual gives you the procedures and data the job requires.

File Details

• Manual type: Maintenance / Overhaul Manual
• Brand: Bendix/King (AlliedSignal Electronic and Avionics Systems)
• Equipment covered: KR 87 Automatic Direction Finder, KI 227 / KI 228 ADF Indicators, KA 44 / KA 44B ADF Antennas
• Manual number: 006-05184-0007
• Revision: 7, July 1998
• Language: English
• Format: PDF (digital download)
• Contents include: Installation, Operation, Theory of Operation, Test Procedures, Alignment, Overhaul, Troubleshooting, Illustrated Parts List

Chapters Covered

• Section I — Introduction
  • Equipment Description, Technical Characteristics, Units and Accessories Supplied
  • License Requirements, Requirements for a Fully TSO’d System
• Section II — Installation
  • Unpacking and Inspecting, Cooling Considerations
  • KR 87 Mounting Tray, KI 227/228, KA 44/44B Antenna Installation
  • Flight Timer Reset Switch and Elapsed Timer Alarm Installation
  • Cable Harness and Connector Assembly (Molex terminal instructions)
  • Post Installation Checks — System Check, Quadrantal Error Adjustment, Operational Checks
• Section III — Operation
  • Operating Procedures, Operating Modes, Frequency Control
  • Timers — Flight Timer and Elapsed Timer
  • Indicator Operation
• Section IV — Theory of Operation
  • Basic ADF Principles, Phase-Modulated Pointing Systems
  • Block Diagram Discussion — KA 44/44B Antenna, RF Section, Phase Detector and Pointing Circuitry, Power Supply, Microprocessor, Switching and Display
  • Detailed Circuit Theory — RF Section, Audio and AGC, LSI Frequency Synthesizer, Phase Detector, Bearing Pointer Circuitry, Microprocessor, Gas Discharge Display Multiplex, Display Dimming, Power Supply
• Section V — Test Procedures
  • Test Equipment Required, Operational Test Setup
  • Input Current, Sensitivity, ADF Sensitivity, Indicator Output Voltage
  • Display Functions and Timer Test, Display Dimming, Bearing Accuracy
  • Alignment — Power Supply, RF Preselector, Crystal Oscillator, Mixer L.O. Level, IF, Coherent Detector, Crystal Filter Center Frequency, AGC Level, Mixer Bias, Indicator Driver Level, Photocell Dimming, Rotational Bias
  • Overhaul — Inspection, Cleaning, Repair, Disassembly/Assembly
  • Troubleshooting — System, Power Supply, LSI Synthesizer, RF and IF, Coherent Detector, Bearing Detector and Driver, Display, Display Dimming, Processor
• Section VI — Illustrated Parts List
  • ADF Receiver Board, RF Amp Board, Main Board, Display Board, Power Supply Board
  • Final Assembly drawings, assembly drawings, and schematics for each board

The manual opens with an equipment description and full technical characteristics for the KR 87 receiver, the KI 227 and KI 228 indicators, and the KA 44/KA 44B antennas, including TSO compliance, environmental specs, physical dimensions, weights, power requirements, frequency range, receiver sensitivity and selectivity, bearing accuracy, audio output, and alarm output. From there, installation covers mounting tray cutout dimensions, antenna location guidelines with QE adjustment, flight timer reset wiring in both normally open and normally closed configurations, elapsed timer alarm wiring, Molex crimping and connector assembly, and post-installation system checks. Operation section explains the ANT and ADF modes, BFO function, frequency control, flight timer and elapsed timer functions, and the manual versus slaved compass card indicator operation.

The theory of operation section is unusually thorough for an avionics manual, walking through the plane electromagnetic wave, induced voltages versus relative bearing, the 32Hz phase-modulated pointing system with phasor diagrams, the phase detector’s two phase-locked loops and lock detectors, bearing pointer circuitry with the voltage shaping network, the LSI frequency synthesizer charge pump, the microprocessor and EAROM circuitry, gas discharge display multiplexing, display dimming duty cycle and current control, and the ringing choke power supply.

The test and alignment section provides a complete test setup using the KTS 156 antenna simulator and lists every adjustment — RF preselector alignment through all four half-octave bandpass filters, crystal oscillator frequency at 2.048MHz, mixer L.O. level, IF alignment for maximum AGC, coherent detector adjustment at 139.8kHz, crystal filter center frequency, AGC level, mixer bias, indicator driver level, photocell dimming, and rotational bias. The troubleshooting section includes nine detailed flowcharts plus step-by-step procedures for system, power supply, LSI synthesizer, RF and IF, coherent detector, bearing detector and driver, display, display dimming, and processor faults, with a bearing detector troubleshooting guide giving expected duty cycle and DC voltages at test points for each relative bearing.

What This Manual Enables You to Do

With this Bendix King KR 87 ADF maintenance manual, you can perform full bench testing, alignment, and repair of the KR 87 receiver, including RF preselector sweep alignment, coherent detector setup, bearing pointer calibration, and display dimming adjustment. You can diagnose no-lock, no-audio, improper-pointing, display blanking, and power supply faults using the flowcharts and expected voltages. You can also service the KI 227 and KI 228 indicators, adjust quadrantal error at the antenna, install a flight timer reset switch or elapsed timer alarm, and identify every board-level component through the illustrated parts lists and schematics.

Correct procedures and exact alignment values matter on ADF equipment — a misadjusted coherent detector or crystal filter will leave the bearing pointer wandering or the receiver unable to lock. This manual supplies the nominal voltages, waveform references, and adjustment sensitivities needed to bring the unit back to specification. The PDF is delivered instantly after payment, requires no shipping, and can be viewed on any device or printed for use at the bench.

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