Kenwood KAC-929 Service Manual

Product Overview

The Kenwood KAC-929 is a powerful car audio amplifier designed to deliver high-quality sound. This service manual provides detailed information for servicing and maintaining the unit.

Block Diagram

The block diagram illustrates the internal signal flow and component interactions within the KAC-929. Key functional blocks include:

• Isolation Amplifier
• Input Sensitivity and Bass Boost circuits
• Mixer and Low Pass Filter (LPF)
• Expander and Inverter circuits
• Buffer and Mute stages
• Differential Stage and B-Class Stage
• DC Detector, Overload Detector, and Thermal Protection circuits

Circuit Description

Expander Circuit

The expander circuit is designed to enhance the dynamic range of the audio signal. It amplifies variations in the input signal, making loud sounds louder and quiet sounds quieter. Figure 1 and Figure 2 in the original document illustrate the characteristics of this circuit compared to an ordinary amplifier.

Adjustment

The service manual details the adjustment procedure for the idle current. This involves connecting a DC voltmeter to specific points (CN2 L/R and J2 SP.OUT L+/R-) and adjusting VR3 (Lch) and VR4 (Rch) to achieve a reading of 2.5mV.

PC Board Layouts

The document includes component side and foil side views of the main Printed Circuit Board (PC Board). These diagrams show the placement of various components, including ICs, transistors, resistors, and capacitors, along with their reference designators and locations.

Parts List

A comprehensive parts list is provided, detailing each component with its reference number, part number, description, and quantity. This includes panels, heatsinks, fans, fuses, screws, connectors, ICs, transistors, diodes, capacitors, resistors, and variable resistors.

Specifications

Audio Section

• Max Power Output (4Ω): 300W x 2 (Normal), 1000W x 1 (Bridge)
• Rated Power Output (4Ω): 150W x 2 (Normal, 20Hz-20KHz, 0.08% THD), 460W x 1 (Bridge, 1KHz, 0.8% THD)
• Frequency Response: 5Hz - 50kHz (+0, -1dB)
• Signal to Noise Ratio: 100dB
• Sensitivity (MAX): 0.2V

General

• Operating Voltage: 11V-16V
• Current Consumption: 43A (1KHz, 10% THD)
• Installation Size: 261mm x 57mm x 350mm
• Weight: 4.6kg

Company Information

Contact information for various Kenwood regional offices is provided, including Kenwood Corporation (Japan), Kenwood Service Corporation (USA), Kenwood Electronics Canada Inc., Kenwood Electronics Deutschland GmbH, Kenwood Electronics France S.A., Kenwood Electronics Belgium N.V., Kenwood Electronics Italia S.p.A., Kenwood Ibérica S.A., Kenwood Electronics Australia Pty. Ltd., Kenwood Electronics (Hong Kong) Ltd., Kenwood Electronics Gulf FZE, Kenwood Electronics (Thailand) Co., Ltd., Kenwood Electronics Singapore Pte Ltd., and Kenwood Electronics (Malaysia) Sdn Bhd.