Audio Electronics Repair Course

Lesson 1 • Chemical and Thermal Hazard Management

This deals with flux fumes, solvents, and soldering iron burns as normal workshop hazards. It establishes the 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. It links proper grounding habits to reducing component loss during repair.

Lesson 3 • Electrical Safety and Hazard Control

Covers shock prevention, fuse protection, and safe handling of mains-connected equipment. This is mandatory knowledge before any live-circuit work in later chapters.

Lesson 1 • Reading Audio Schematics

Develops the ability to interpret schematic symbols and trace signal paths. This 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. This establishes the quantitative language used throughout the course.

Lesson 3 • Passive Components Identification

Teaches you to recognise and understand the function of resistors, capacitors, and inductors in audio gear. It 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. This 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. This prepares students to safely diagnose output-stage failures.

Lesson 2 • Signal Processors and Effects Units

Surveys compressors, equalisers, reverb units, and delay lines as separate 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. It establishes how the transducer type determines circuit requirements.

Lesson 4 • Mixing Consoles and Signal Routing

Covers channel strip architecture, bus routing, and summing amplifiers in analogue consoles. It 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. This 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 Trace Restoration

Teaches lifted pad repair, trace bridging, and via restoration on damaged audio boards. This enables you to recover 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. This prevents pad and trace damage that would complicate later repairs.

Lesson 1 • DC Voltage and Bias Measurements

Teaches systematic voltage mapping against schematic values to locate biasing faults. It 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. This prevents random part replacement and reduces repair time.

Lesson 3 • Intermittent and Noise Fault Isolation

Addresses the hardest fault class: intermittent failures and noise artifacts caused by cold joints or aging components. It teaches thermal and mechanical stress testing.

Lesson 4 • Signal Tracing Techniques

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

Lesson 1 • Linear Power Supply Operation

Explains the transformer, rectifier, filter, and regulator stages in a linear supply. This 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. It 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. This 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. It includes reforming procedures for equipment that has been stored for a long time.

Lesson 1 • Output Stage Replacement Procedures

Guides safe removal and installation of output transistors, including thermal interface preparation. Incorrect procedure causes new devices to fail again immediately.

Lesson 2 • Performance Verification and Burn-In

Uses THD measurement, frequency response sweep, and extended load testing to confirm repair quality. This catches latent failures before the 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. This 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. This 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 that cause 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. This distinguishes digital failures from analogue ones before you open the device.

Lesson 4 • Hybrid Device Integration Testing

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