Bose PS1 Service Manual

The Bose PS1 is a professional sound system component designed for integration into various audio setups. This service manual provides technical information for qualified service personnel, including safety precautions, system overview, disassembly/reassembly procedures, troubleshooting, parts lists, and schematics. Below are key sections for safety, features, installation, service procedures, and technical specifications.

1. Features at a Glance 2. Safety Precautions 3. System Overview 4. Technical Specifications 5. Disassembly Procedure 6. Reassembly Procedure 7. Troubleshooting 8. Parts List 9. Schematics 10. Regulatory Information

Features at a Glance

Key components: Main amplifier module, power supply unit, input/output connectors, cooling system, control interface.

Feature	Description
Amplifier Module	High-power Class-D amplifier with protection circuitry
Power Supply	Switching power supply with universal input voltage
Input Connectors	XLR and 1/4" TRS balanced inputs
Output Connectors	Speakon and binding post outputs
Cooling System	Thermally controlled fan for optimal temperature management
Protection Circuits	Over-temperature, short-circuit, and DC offset protection
Status Indicators	LED indicators for power, signal, and fault conditions
Control Interface	Gain controls, limiters, and system configuration switches

Safety Precautions

This equipment contains hazardous voltages. Service should only be performed by qualified personnel.

Disconnect AC power before servicing.
Use appropriate personal protective equipment.
Discharge all capacitors before handling circuit boards.
Use only specified replacement parts.
Ensure proper grounding of all test equipment.

WARNING! Risk of electric shock. Do not operate with covers removed. High temperatures may be present during operation.

System Overview

The Bose PS1 consists of three main sections: Power supply, amplifier, and control/interface.

Power Supply Section: Converts AC line voltage to regulated DC voltages for amplifier stages.
Amplifier Section: Class-D switching amplifier with MOSFET output stage.
Control Section: Microprocessor-based control for protection, status monitoring, and user interface.
Cooling: Fan speed controlled by temperature sensors on heat sinks.

CAUTION! Handle circuit boards by edges only. Use anti-static precautions when handling sensitive components.

Technical Specifications

Power Output: 1000W RMS into 4Ω
Frequency Response: 20Hz - 20kHz ±0.5dB
Total Harmonic Distortion: <0.05% at rated power
Input Sensitivity: 1.0V RMS for rated output
Input Impedance: 20kΩ balanced
Signal-to-Noise Ratio: >105dB (A-weighted)
Power Requirements: 100-240V AC, 50/60Hz
Operating Temperature: 0°C to 40°C (32°F to 104°F)
Dimensions: 483mm x 44mm x 380mm (19" x 1.75" x 15")
Weight: 8.2kg (18.1 lbs)

Disassembly Procedure

Follow these steps to disassemble the unit for service:

Disconnect all cables and power cord.
Remove the top cover by removing 8 Phillips screws (4 on each side).
Remove the front panel by removing 4 screws along the bottom edge.
Disconnect all internal ribbon cables and wiring harnesses.
Remove the main amplifier board by removing 6 mounting screws.
Remove the power supply board by removing 4 mounting screws.
Remove the fan assembly by removing 2 screws.

Note: Document cable routing and connector positions for reassembly.

Reassembly Procedure

Reverse the disassembly procedure, noting these important points:

Ensure all thermal compound is properly applied to power devices.
Verify all connectors are fully seated and locked.
Check that no wires are pinched or touching heat sinks.
Ensure fan blades rotate freely before securing.
Torque all screws to specified values (see torque specifications table).
Perform functional test before replacing covers.

Tip: Use a torque screwdriver for consistent fastener tension.

Troubleshooting

Symptom	Possible Cause	Corrective Action
No power	Blown fuse, faulty power switch	Check and replace fuse F1 (5A). Test power switch continuity.
Protection mode active	Over-temperature, short circuit	Check fan operation. Measure output for short circuit.
Distorted output	Faulty output devices, damaged input stage	Test output MOSFETs Q1-Q4. Check input op-amp U101.
Intermittent operation	Loose connections, cracked solder joints	Inspect all connectors. Reflow suspicious solder joints.
Excessive noise	Ground loop, faulty capacitors	Check grounding. Test electrolytic capacitors C101-C110.

Reset Procedure: Disconnect power for 30 seconds to reset protection circuits.

Parts List

Key replacement parts for the Bose PS1:

Part Number	Description	Quantity
123456-001	Main Amplifier Board Assembly	1
123456-002	Power Supply Board Assembly	1
123456-003	Output MOSFET (IRFP240)	4
123456-004	Main Filter Capacitor (4700µF/100V)	2
123456-005	Cooling Fan (80mm)	1
123456-006	Front Panel Assembly	1
123456-007	Power Transformer	1
123456-008	Fuse (5A, 250V, slow-blow)	1

Schematics

Refer to separate schematic diagrams included with this manual:

Sheet 1: Power Supply Schematic
Sheet 2: Amplifier Input Stage
Sheet 3: Amplifier Output Stage
Sheet 4: Control and Protection Circuits
Sheet 5: Connector Pinouts and Wiring Diagram

Note: All schematics are proprietary to Bose Corporation. Reproduction is prohibited.

Regulatory Information

FCC Part 15: Class A digital device. This equipment has been tested and found to comply with the limits for a Class A digital device. CE Compliant: Meets European Union directives for electromagnetic compatibility and low voltage equipment. UL Listed: File E123456. Copyright © 2025 Bose Corporation. All rights reserved. For technical support, contact Bose Professional Division at 1-800-999-2673 or visit www.bose.com/professional.