The Sharp JC-202 is a portable cassette player, available in red, black, and white, designed for personal audio enjoyment. It comes in two main configurations: one with inner-ear type headphones and another with over-head type headphones. This service manual provides comprehensive information for its operation, maintenance, and repair.
Function Description:
The JC-202 is primarily a compact cassette deck, featuring auto-reverse functionality, which allows continuous playback without manually flipping the tape. It incorporates a graphic equalizer for sound customization, enabling users to adjust the audio output to their preference. The device is designed for portability, powered by either internal batteries or an external DC power supply. It includes standard controls for playback, stop, fast forward, and rewind, along with a volume control and an LED indicator for power and battery status. Headphone jacks are provided for private listening.
Important Technical Specifications:
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General:
- Power Source: The unit operates on 3V DC, supplied by two UM/SUM-3 or R6 batteries, or an external 3V DC power supply.
- Output Power (Europe): Maximum output is 50 mW (25 mW + 25 mW) for DC operation. RMS output is 36 mW (18 mW + 18 mW) for DC operation (DIN 45 324).
- Output Power (Other than Europe): Maximum output is 50 mW (25 mW + 25 mW) for DC operation. RMS output is 36 mW (18 mW + 18 mW) for DC operation with 10% distortion.
- Dimensions: The unit measures 88 mm (width) x 116 mm (height) x 37 mm (depth).
- Weight: Approximately 260 g without batteries.
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Tape Deck:
- Tape Type: Compact cassette tape.
- Frequency Response: 100-10,000 Hz.
- Signal/Noise Ratio: 54 dB.
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Headphones:
- Type: Available with over-head or inner-ear type headphones.
- Impedance: 32 ohms.
Usage Features:
The JC-202 is designed for ease of use on the go.
- Headphone Sockets: Multiple headphone jacks are available for shared listening or different headphone types.
- Power/Battery Indicator: An LED provides visual feedback on the power status and battery level.
- Volume Control: A rotary knob allows for precise adjustment of the audio output level.
- External DC Power Input Socket: Enables operation from an external power adapter, conserving battery life.
- Graphic Equalizer: Five frequency bands (100Hz, 300Hz, 1kHz, 3kHz, 10kHz) can be adjusted to tailor the sound to personal preferences or music genres.
- Tape Direction Switch: Allows manual selection of tape playback direction or enables the auto-reverse function.
- Stop Button: Halts tape playback.
- Fast Forward/Rewind Buttons: For quick navigation through the tape.
- Play Button: Initiates tape playback.
- Battery Compartment: Houses two UM/SUM-3 or R6 batteries.
- Belt Clip: For convenient carrying and hands-free use.
The device's compact size and lightweight design, combined with battery power, make it highly portable for personal listening. The auto-reverse feature enhances convenience by eliminating the need to manually flip the cassette.
Maintenance Features:
The service manual provides detailed instructions for disassembly, adjustment, and replacement of parts, ensuring the longevity and optimal performance of the JC-202.
- Disassembly: Step-by-step procedures are outlined for disassembling the rear cabinet, main PWB, mechanism, and graphic equalizer PWB. This includes instructions for removing screws and disconnecting wires.
- Adjustment:
- Driving Force Check: Procedures for measuring torque meter values for play and reverse play (TW-2412 and TW-2422, respectively), with specified values (Over 50 g).
- Torque Check: Detailed checks for play (TW-2111), reverse play (TW-2121), fast forward (TW-2231), and rewind (TW-2231) torque, with specified ranges (27 to 43 g.cm for play/reverse, Over 60 g.cm for fast forward/rewind).
- Head Azimuth Adjustment: Involves using a test tape (MTT-114) and an instrument connection (headphones with 32 ohms load resistance) to ensure proper alignment of the tape head.
- Tape Speed Adjustment: Utilizes a test tape (MTT-111) and adjusts VR1 to achieve a frequency of 3,000 ± 60 Hz, measured with headphones (32 ohms).
- Schematic Diagram and Wiring Side of P.W.Board: These diagrams are crucial for troubleshooting and repair, illustrating the electrical connections and component layout. Notes on the schematic diagram clarify resistor and capacitor unit symbols, voltage measurements, and the audio circuit mode.
- Exploded Views: Detailed exploded diagrams for both the mechanism and cabinet facilitate easy identification and reassembly of parts.
- Replacement Parts List: A comprehensive list of integrated circuits, diodes, controls, capacitors, other circuitry parts, and mechanical parts, along with their part numbers, descriptions, and codes. This list is essential for ordering correct replacement components.
- Packing Method: Instructions for packing the unit, specifically for UK models, ensure safe transportation and storage.
- User Safety: The manual emphasizes that for user safety, the set should be restored to its original condition using only identical specified parts during any repair or maintenance.
The JC-202's design and accompanying service manual reflect a commitment to both user experience and maintainability, allowing for extended product life through proper care and repair.
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