Audio Equipment Repair Course

Lesson 1 • Chemical and Thermal Hazard Management

Addresses flux fumes, solvents, and soldering iron burns as routine workshop hazards. Establishes ventilation and first-aid protocols used throughout the course.

Lesson 2 • Electrostatic Discharge Prevention

Teaches ESD risks specific to audio ICs, FETs, and digital components. Connects proper earthing habits to reduced component loss during repair.

Lesson 3 • Electrical Safety and Hazard Control

Covers shock prevention, fuse protection, and safe handling of mains-connected equipment. Mandatory knowledge before any live-circuit work in subsequent chapters.

Lesson 1 • Reading Audio Schematics

Develops the ability to interpret schematic symbols and trace signal paths. Directly enables fault diagnosis in later chapters.

Lesson 2 • Core Electrical Concepts for Audio

Covers voltage, current, resistance, and power as they apply to audio circuits. Establishes the quantitative language used throughout the course.

Lesson 3 • Passive Components Identification

Teaches recognition and function of resistors, capacitors, and inductors in audio gear. Connects component behaviour to audible symptoms when they fail.

Lesson 4 • Active Components in Audio Circuits

Introduces transistors, diodes, and integrated circuits as signal-processing elements. Prepares students to trace signal flow through amplification stages.

Lesson 1 • Power Amplifiers and Speaker Systems

Analyses Class A, AB, D, and H amplifier topologies and their loudspeaker interfaces. Prepares students to diagnose output-stage failures safely.

Lesson 2 • Signal Processors and Effects Units

Surveys compressors, equalisers, reverb units, and delay lines as discrete repair targets. Students identify the functional blocks inside each processor type.

Lesson 3 • Microphones and Preamplifiers

Examines dynamic, condenser, and ribbon mic designs alongside their matching preamp stages. Establishes how transducer type dictates circuit requirements.

Lesson 4 • Mixing Consoles and Signal Routing

Covers channel strip architecture, bus routing, and summing amplifiers in analogue consoles. Connects topology knowledge to systematic fault isolation.

Lesson 1 • Surface-Mount Component Soldering

Introduces hot-air rework, fine-pitch IC soldering, and paste application for SMD work. Extends repair capability to modern compact audio hardware.

Lesson 2 • Soldering Iron Selection and Care

Covers tip types, temperature control, and station maintenance for consistent joint quality. Proper iron care directly extends tip life and joint reliability.

Lesson 3 • PCB Repair and Track Restoration

Teaches lifted pad repair, track bridging, and via restoration on damaged audio boards. Enables recovery of boards that would otherwise be scrapped.

Lesson 4 • Desoldering Methods and Tools

Covers solder wick, vacuum pumps, and hot-air removal for safe component extraction. Prevents pad and track damage that would complicate subsequent repairs.

Lesson 1 • DC Voltage and Bias Measurements

Teaches systematic voltage mapping against schematic values to locate biasing faults. Connects out-of-spec voltages to specific failed components.

Lesson 2 • Diagnostic Methodology Overview

Establishes a repeatable fault-finding process: symptom analysis, hypothesis formation, and verification. Prevents random part replacement and reduces repair time.

Lesson 3 • Intermittent and Noise Fault Isolation

Addresses the hardest fault class: intermittent failures and noise artefacts caused by cold joints or ageing components. Teaches thermal and mechanical stress testing.

Lesson 4 • Signal Tracing Techniques

Uses oscilloscope and audio probe to follow signal through stages until loss or distortion is found. Directly locates the faulty stage in multi-block devices.

Lesson 1 • Linear Power Supply Operation

Explains transformer, rectifier, filter, and regulator stages in linear supplies. Provides the circuit model used for all linear supply fault diagnosis.

Lesson 2 • Diagnosing Power Supply Faults

Applies voltage mapping and ripple measurement to locate failed rectifiers, capacitors, and regulators. Connects supply faults to downstream audio symptoms.

Lesson 3 • Switching Power Supply Fundamentals

Covers flyback, forward, and half-bridge SMPS topologies common in powered speakers and interfaces. Prepares students for high-frequency fault diagnosis.

Lesson 4 • Capacitor Replacement and Reforming

Teaches correct electrolytic capacitor selection, polarity, and voltage rating for supply rebuilds. Includes reforming procedures for long-stored equipment.

Lesson 1 • Output Stage Replacement Procedures

Guides safe removal and installation of output transistors, including thermal interface preparation. Incorrect procedure causes immediate re-failure of new devices.

Lesson 2 • Performance Verification and Burn-In

Uses THD measurement, frequency response sweep, and extended load testing to confirm repair quality. Catches latent failures before equipment is returned to service.

Lesson 3 • Preamplifier and Input Stage Faults

Diagnoses noise, DC offset, and gain errors in input and preamp stages using signal tracing. Builds on voltage measurement skills from the diagnostic chapter.

Lesson 4 • Bias Adjustment and Quiescent Current

Teaches idle current measurement and trimmer adjustment to minimise crossover distortion and heat. Correct bias is the single most critical amplifier alignment step.

Lesson 1 • Network Audio and Control Bus Faults

Addresses faults in Ethernet-based audio transport, MIDI, and RS-485 control buses. Enables repair of stage boxes, digital snakes, and remote-controlled devices.

Lesson 2 • Clock and Synchronisation Repair

Diagnoses crystal oscillator, PLL, and word clock distribution faults causing jitter or sync loss. Clock integrity underlies all digital audio performance.

Lesson 3 • Digital Audio Fault Characteristics

Identifies the unique symptoms of digital faults: dropouts, clicks, bit errors, and silence. Distinguishes digital failures from analogue ones before opening the device.

Lesson 4 • Hybrid Device Integration Testing

Validates repaired hybrid devices by testing analogue and digital domains together under real-world signal conditions. Confirms end-to-end performance before sign-off.