The Bose AV3 2 1 is a 3-2-1 home entertainment system comprising a media center, two front speakers, and a Acoustimass module. This repair manual provides detailed instructions for diagnosing, servicing, and repairing common issues. Below are key sections for safety, system overview, disassembly, troubleshooting, component testing, and reassembly.
Before attempting any repair, ensure the system is disconnected from AC power. Allow capacitors to discharge. Use appropriate ESD protection when handling circuit boards.
| Hazard | Precaution |
|---|---|
| Electrical Shock | Unplug unit. Verify no voltage with multimeter before touching internal components. |
| ESD Damage | Use grounded wrist strap and anti-static mat when handling PCBs. |
| Heat & Burns | Allow power supply and amplifier heatsinks to cool completely. |
| Mechanical Injury | Use correct tools. Beware of sharp edges inside chassis. |
| Component Damage | Label cables and screws during disassembly. Handle ribbon cables with care. |
The Bose AV3 2 1 system includes a Media Center (DVD/CD player, AM/FM tuner, amplifier), two Direct/Reflecting cube speakers, and an Acoustimass bass module.
WARNING! Using incorrect tools may damage fasteners and void warranty.
Media Center Chassis:
CAUTION! Note screw locations and lengths. Take photos during disassembly for reference.
Use DMM to test key components in-circuit where possible, or desolder for out-of-circuit verification.
| Component | Test Procedure | Expected Value |
|---|---|---|
| Main Fuse (F1) | Continuity test | Near 0 ohms |
| Power Transformer | Resistance primary/secondary | See schematic (typically 10-100Ω primary) |
| Output Transistors (Q101-Q104) | Diode test across B-C, B-E, C-E | B-C/B-E: ~0.6V forward; C-E: open circuit |
| Electrolytic Capacitors | ESR meter or capacitance test | Within ±20% of marked value; low ESR |
| Voltage Regulators (78xx, 79xx) | Measure input/output voltage with power applied | Output = rated voltage (e.g., +5V, ±12V) |
No Power (LED off): Check AC cord, fuse F1, power switch, primary side of power supply. Replace bridge rectifier or switching IC if faulty.
No Audio (Power LED on): Check mute circuit transistors. Test audio op-amps for correct supply voltages. Inject signal at various stages to isolate fault.
Disc Read Error: Clean laser lens with isopropyl alcohol. Check sled motor operation. Replace laser pickup assembly (KSS-213C or similar) if adjustment fails.
Distorted Audio/Protection Mode: Test output transistors for shorts. Check emitter resistors (0.22Ω/5W). Verify DC offset at speaker outputs (<50mV).
Remote Not Working: Test IR receiver module voltage (typically 5V). Check remote with phone camera for IR LED activity.
| Part Number | Description | Qty |
|---|---|---|
| 145892 | Main Power Fuse, 2.5A, 250V, Slow-Blow | 1 |
| 208783 | Laser Pickup Assembly (for DVD/CD) | 1 |
| 312456 | Output Transistor, 2SC5200 / 2SA1943 Pair | 2 pair |
| 401237 | Main Electrolytic Capacitor, 4700µF 50V | 2 |
| 556789 | IR Receiver Module, 3-pin | 1 |
| 678901 | Front Panel Button Membrane | 1 |
| 789012 | Power Transformer, Primary 120V | 1 |
Note: Always verify part numbers with Bose service portal or schematic.
Tip: Apply fresh thermal paste to power transistors and heatsink during reassembly.
To reset system microprocessor and clear error codes:
Speaker Calibration: Use setup microphone (if included) and follow on-screen prompts in setup menu to optimize sound for room.
This product complies with FCC Part 15 Class B. Any unauthorized modification may void the user's authority to operate the equipment. Contains laser product of Class 1. Copyright © Bose Corporation. All trademarks are property of Bose Corporation. For service inquiries, contact authorized Bose service centers only.
| Symptom | Diagnostic Step 1 | Diagnostic Step 2 | Likely Fault |
|---|---|---|---|
| Unit dead, no LED | Check AC power & fuse F1 | Test primary voltage on power board | Blown fuse, faulty power switch, dead transformer |
| Power LED on, no sound | Check speaker connections | Test for protection mode (relay click) | Shorted output transistor, open emitter resistor |
| Disc spins, no read | Clean laser lens | Check laser power with oscilloscope | Weak laser diode, faulty sled mechanism |
| Intermittent operation | Check for cold solder joints | Monitor power supply voltages under load | Cracked solder on large components, failing capacitor |
| No video output | Verify input source & cable | Check video encoder chip voltages | Faulty video DAC or output buffer |
Advanced: Refer to official Bose service manual (part # 123456) for detailed schematics and board layouts.
Service Support: Authorized service centers only. Do not attempt repairs beyond your skill level.