Kenwood KA 6100 Service Manual

The Kenwood KA 6100 is a high-quality stereo integrated amplifier featuring 60 watts per channel RMS, phono input for turntables, tape monitor circuits, loudness control, tone controls, and multiple audio inputs. This service manual provides detailed technical information, schematics, alignment procedures, and troubleshooting guides for qualified service technicians. Below are key sections covering specifications, block diagrams, circuit descriptions, adjustment procedures, and parts list.

1. Specifications 2. Block Diagram 3. Circuit Description 4. Disassembly Instructions 5. Adjustment Procedures 6. Schematic Diagrams 7. Parts List 8. PCB Layouts 9. Troubleshooting Guide 10. Safety Precautions

Specifications

Technical specifications for the Kenwood KA 6100 integrated amplifier.

ParameterSpecification
Power Output60W + 60W (RMS, 8Ω, 20Hz-20kHz)
Total Harmonic Distortion0.02% (at rated output)
Frequency Response10Hz-50kHz (+0, -1dB)
Input SensitivityPhono: 2.5mV; Aux: 150mV
Signal-to-Noise RatioPhono: 76dB; Aux: 100dB
Tone ControlsBass: ±10dB at 100Hz; Treble: ±10dB at 10kHz
Power SupplyAC 120V/220V/240V, 50/60Hz
Dimensions430(W) x 145(H) x 310(D) mm
Weight8.5 kg
Power Consumption220W (max)

Block Diagram

System block diagram showing signal flow and major components.

  1. Input Selector: Phono, Aux, Tuner, Tape 1, Tape 2
  2. Phono Equalizer: RIAA compensation circuit
  3. Tone Control: Bass and treble adjustment circuits
  4. Volume Control: ALPS potentiometer
  5. Power Amplifier: Complementary symmetry output stage
  6. Protection Circuit: DC detection and relay protection
  7. Power Supply: Transformer, rectifier, and filter capacitors

WARNING! High voltages present - discharge capacitors before servicing.

Circuit Description

Detailed explanation of major circuit sections.

  1. Phono Stage: Low-noise transistor array with RIAA equalization
  2. Pre-amplifier: Voltage amplifier with tone control circuits
  3. Power Amplifier: Direct-coupled complementary output
  4. Protection Circuit: Speaker relay with DC offset detection
  5. Power Supply: Dual voltage rails (+/- supplies)

CAUTION! Use proper grounding techniques when testing live circuits.

Disassembly Instructions

Adjustment Procedures

Required test equipment: oscilloscope, audio generator, DMM, dummy loads.

DC Offset: Adjust VR301/VR302 for 0mV ±5mV at speaker terminals

Bias Current: Adjust VR303/VR304 for 20mA across emitter resistors

Phono Equalization: Verify RIAA response with test records

Power Output:Verify 60W RMS into 8Ω load with <1% THD

Schematic Diagrams

Complete schematics for all circuit boards.

  1. Main Amplifier Board (X50-1290-10)
  2. Power Supply Board (X50-1291-10)
  3. Protection Circuit Board (X50-1292-10)
  4. Front Panel Board (X50-1293-10)
  5. Input Selector Board (X50-1294-10)

Tip: Use original schematics for accurate component values.

Parts List

Complete component listing with Kenwood part numbers.

ReferenceDescriptionPart Number
Q701-Q704Output Transistor 2SC25812SC2581
Q705-Q708Output Transistor 2SA11062SA1106
D701-D704Rectifier Diode 1S18861S1886
C701,C702Main Filter 10000μF/63VECA-1JM103
VR301,VR302DC Offset Adjust 100ΩX93-1090-00
VR303,VR304Bias Adjust 200ΩX93-1091-00
RY701Protection Relay MY4-02MY4-02
F701,F702Main Fuse 4A4A

PCB Layouts

Printed circuit board layouts and component placement diagrams.

  1. Main Board Component Side
  2. Main Board Solder Side
  3. Power Supply Board Layout
  4. Protection Circuit Board
  5. Front Panel Board

WARNING! Observe polarity when replacing electrolytic capacitors.

Troubleshooting Guide

SymptomPossible CauseCorrective Action
No powerBlown fuse, faulty switchCheck F701/F702; test power switch
No soundProtection relay, dead channelCheck RY701; measure output transistors
DistortionBias current, faulty transistorsAdjust bias; test output devices
DC offset highInput stage imbalanceAdjust VR301/VR302; check differential pair
HumGrounding, filter capacitorsCheck ground connections; test C701/C702

Reset: Recalibrate after component replacement.

Service: Use genuine Kenwood parts for best performance.

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