Marantz PMD 201 Service Manual

The Marantz PMD 201 is a professional portable cassette recorder designed for field recording, journalism, and professional audio applications. This service manual provides comprehensive technical information for qualified service personnel, including schematics, alignment procedures, parts lists, and troubleshooting guidelines for maintaining and repairing the PMD 201 recorder.

1. Specifications 2. Block Diagrams 3. Circuit Descriptions 4. Disassembly Procedures 5. Alignment and Adjustment 6. Troubleshooting Guide 7. Parts List 8. PCB Layouts 9. Schematics 10. Mechanical Drawings 11. Service Notes

Specifications

Technical specifications and performance characteristics of the Marantz PMD 201 portable cassette recorder.

ParameterSpecification
TypeStereo cassette recorder
Heads3-head system (erase, record, playback)
Frequency Response40Hz - 14kHz (±3dB)
Signal-to-Noise Ratio50dB (Dolby off)
Wow and Flutter0.15% (WRMS)
InputsMic, Line, External DC
OutputsLine, Headphone
Power Supply6V DC (4 x AA batteries or external)
Dimensions180 x 105 x 45 mm
Weight650g (without batteries)

Block Diagrams

System block diagrams showing signal flow and functional relationships between major circuit sections.

  1. Overall System Block Diagram: Shows complete signal path from input to output.
  2. Record Amplifier Block Diagram: Detailed record signal processing.
  3. Playback Amplifier Block Diagram: Playback signal chain and processing.
  4. Power Supply Block Diagram: DC power distribution and regulation.
  5. Motor Control Block Diagram: Tape transport control system.

WARNING! Service should only be performed by qualified technicians with proper test equipment.

Circuit Descriptions

Detailed descriptions of major circuit sections and their operation.

  1. Record Amplifier Circuit: Explains bias oscillator, record equalization, and Dolby NR.
  2. Playback Amplifier Circuit: Covers playback EQ, Dolby decoding, and output stages.
  3. Power Supply Circuit: Describes battery operation, DC-DC conversion, and regulation.
  4. Motor Control Circuit: Details capstan servo, reel motor control, and logic circuits.
  5. Microphone Preamplifier: Low-noise mic preamp design and characteristics.

CAUTION! Always disconnect power before servicing and observe ESD precautions.

Disassembly Procedures

Alignment and Adjustment

Required test equipment and step-by-step alignment procedures.

Test Equipment Required: Audio oscillator, oscilloscope, wow/flutter meter, AC millivoltmeter, test tapes, dummy load.

  1. Playback Amplifier Adjustment: Using standard test tape for frequency response.
  2. Record Amplifier Adjustment: Bias current optimization and record EQ adjustment.
  3. Head Azimuth Alignment: Using 6.3kHz or 10kHz test tape for proper head alignment.
  4. Dolby Level Adjustment: Setting correct Dolby reference levels.
  5. Motor Speed Adjustment: Setting correct tape speed using 3kHz test tape.

Troubleshooting Guide

Common problems, probable causes, and corrective actions.

SymptomPossible CauseCorrective Action
No powerBatteries, power switch, DC jackCheck battery polarity; test power switch; inspect DC jack.
No sound playbackHead connections, playback ampCheck head wiring; test playback amplifier stages.
Poor recordingBias oscillator, record headVerify bias oscillation; check record head condition.
Motor not runningMotor, control circuit, beltsTest motor voltage; check control IC; inspect drive belts.
Speed variationMotor, governor, beltsClean speed control pot; check motor; replace worn belts.
Distorted audioAmplifier stages, headsCheck amplifier bias; inspect head wear; test capacitors.

Parts List

Complete list of components with manufacturer part numbers and specifications.

Part No.DescriptionValue/TypeQty
IC101Record/Playback AmplifierLAxxxx1
IC102Dolby Noise ReductionCXxxxx1
Q101-Q115Transistors2SCxxxx15
C101-C250CapacitorsVarious150
R101-R180ResistorsVarious80
MOTOR-01DC Motor6V1
BELT-01Drive BeltFlat1

PCB Layouts

Printed circuit board layouts showing component placement and trace routing.

  1. Main PCB Component Side: Component locations and identifiers.
  2. Main PCB Solder Side: Solder pad locations and trace routing.
  3. Power Supply PCB: Separate power regulation board layout.
  4. Control PCB: Pushbutton and switch circuit board.
  5. Silkscreen Overlays: Component designators and orientation marks.

Tip: Use magnifying glass for identifying small component designators.

Schematics

Complete electrical schematics for all circuit sections.

  1. Main Amplifier Schematic: Complete record/playback amplifier circuit.
  2. Power Supply Schematic: Battery, DC jack, and regulation circuits.
  3. Motor Control Schematic: Capstan and reel motor control circuits.
  4. Input/Output Schematic: Mic preamp, line in/out, and headphone circuits.
  5. Control Logic Schematic: Mode switching and logic control circuits.
  6. Dolby Circuit Schematic: Noise reduction system detailed schematic.

WARNING! Schematics contain proprietary information - for service use only.

Mechanical Drawings

Detailed mechanical drawings and exploded views of assembly.

Chassis Layout: Main chassis dimensions and mounting points.

Mechanism Assembly: Tape transport mechanism exploded view.

Case Assembly: Front and rear case assembly with screw locations.

Control Layout: Button and control positioning drawings.

Head Assembly: Record/playback head mounting details.

Service Notes

Important service information, common modifications, and technical updates.

Service BulletinDateDescription
SN-201-00103/1985Improved head wear compensation circuit
SN-201-00206/1985Motor control IC replacement procedure
SN-201-00309/1985Dolby level calibration update
SN-201-00412/1985Battery contact corrosion prevention
SN-201-00503/1986Drive belt specification change

Service Contacts: Marantz Service Department for technical support and genuine parts.

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