The Bose Acoustimass 15 is a premium home theater speaker system featuring proprietary waveguide technology, a powered Acoustimass module (bass unit), and five Direct/Reflecting cube speakers. This manual provides detailed repair, service, and troubleshooting information for qualified technicians. Below are key sections covering safety, system overview, disassembly, component testing, common repairs, and reassembly procedures.
Key components: Powered Acoustimass bass module, five cube speakers (left/right front, center, left/right rear), system controller/interface module, power supply, and all necessary cables.
| Component | Specification |
|---|---|
| Acoustimass Module | Powered bass unit with built-in amplifier, crossover, and protection circuits. |
| Cube Speakers | Direct/Reflecting design, 2.25" full-range drivers, magnetically shielded. |
| System Power | 120V AC, 60Hz, internal switching power supply. |
| Inputs | Line-level (RCA) for front L/R, center, rear L/R; speaker-level inputs via barrier strips. |
| Outputs | High-level outputs to cube speakers via proprietary connectors. |
| Dimensions (Module) | Approx. 17.5" H x 10.5" W x 17.5" D. |
| Weight (Module) | Approx. 35 lbs. |
| Protection Features | Thermal, over-current, DC offset, and short-circuit protection. |
Before servicing, review all safety warnings. The Acoustimass module contains high voltages and large capacitors that can retain a lethal charge.
WARNING! Failure to follow these precautions can result in severe electrical shock, component damage, or personal injury. Service should only be performed by qualified personnel.
Acoustimass Module:
Cube Speaker:
Amplifier Board: Check for bulging/leaking capacitors, burnt resistors, or cracked solder joints. The output stage uses complementary power transistors. Test with DMM in diode mode.
Power Supply: Primary side includes fuse, bridge rectifier, and switching transistors. Secondary side provides +/- DC voltages for the amplifier. Check fuse first. CAUTION: Primary side is at line voltage.
Bass Driver: A 10" long-throw woofer. Check voice coil continuity (should be 4-8 ohms). Inspect surround and spider for tears or fatigue.
Protection Circuit: A relay on the board mutes the output at power on/off and during faults. Check relay operation and associated driver transistor.
The 2.25" full-range driver is the only serviceable part. Symptoms: no sound, distorted sound, or rattling.
| Component | Test Procedure | Expected Result |
|---|---|---|
| Main Fuse | Visual inspection and continuity test with DMM. | Continuity (0 ohms). |
| Filter Capacitors | Discharge first! Test capacitance with DMM. | Value within +/-20% of rating (e.g., 4700uF). |
| Power Transistors (MOSFETs/BJTs) | Use DMM diode test function between pins. | Refer to datasheet for pinout and expected voltage drops. |
| Rectifier Diodes | Diode test. Remove from circuit for accurate reading. | Forward bias: 0.5-0.7V drop. Reverse bias: OL (open). |
| Resistors | Measure resistance. Compare to color code or schematic. | Value within tolerance band (e.g., 5%, 1%). |
| Symptom | Possible Cause | Corrective Action |
|---|---|---|
| No power (no LED) | Blown fuse, faulty power cord, dead power supply. | Check/Replace fuse (T2A 250V). Test AC input to board. Check primary-side components. |
| Power LED on, but no sound from module | Faulty amplifier section, protection circuit engaged, broken driver. | Check DC offset at speaker output (should be <50mV). Check relay. Test driver continuity. |
| Distorted bass output | Clipping amplifier, damaged voice coil, leaking capacitor. | Check power supply voltages under load. Inspect driver. Replace bulging capacitors. |
| One cube speaker not working | Faulty cube driver, broken wire in cable, bad connection at module. | Swap cube with a known good one to isolate fault. Test driver continuity. Inspect cable. |
| Hum or buzz from module | Ground loop, failing filter capacitor. | Replace main filter capacitors. Ensure all ground connections are secure. |
Genuine Bose replacement parts are required for optimal performance and safety.
To Order: Contact Bose Professional Parts or an authorized Bose service center. Provide the system serial number (located on the rear label of the Acoustimass module).
This manual is for use by qualified service technicians. Unauthorized modifications may void the product warranty and violate safety standards.
Limited Warranty: Refer to the original owner's documentation for warranty terms. Out-of-warranty service is available through Bose authorized service centers.
Service Support: For technical assistance or to locate an authorized service center:
Copyright: This repair manual is provided for informational purposes. Bose, Acoustimass, and Direct/Reflecting are trademarks of Bose Corporation. © [Year] Bose Corporation. All rights reserved.