This document provides a comprehensive service manual for the Sony CFS-903L, an AEP (All European Parts) and UK model radio cassette-corder. The device is a portable audio system designed for both radio reception and cassette tape playback/recording.
Function Description:
The CFS-903L integrates a multi-band radio tuner with a cassette deck, offering versatile audio entertainment. The radio section supports FM, MW (Medium Wave), SW (Short Wave), and LW (Long Wave) bands, allowing users to tune into a wide range of broadcasts. A telescopic antenna is provided for FM reception, while a built-in ferrite rod antenna handles MW and LW. The cassette deck enables playback of pre-recorded tapes and recording from the radio or an external microphone. It features standard tape operation buttons for play, record, fast forward, rewind, stop/eject, and pause. A function selector allows switching between radio and tape modes. The device includes a tone control for adjusting audio output, an OPR/BATT indicator to show operation status and battery level, and a volume control. For private listening, a PHONES jack is available. The unit can be powered by batteries for portability or via an AC power adaptor.
Important Technical Specifications:
- Tuner Frequency Range:
- FM: 87.6 – 107.6MHz
- MW: 531 – 1,602kHz
- LW: 148.5 – 283.5kHz
- SW: 5.95 – 18MHz
- IF (Intermediate Frequency):
- FM: 10.7MHz
- MW/LW/SW: 455kHz
- Frequency Response:
- Speakers:
- 10cm (4 inches) diameter, full range x2
- Outputs:
- Headphones jack (stereo minijack) for 8 – 300ohm impedance headphones
- Maximum Power Output:
- Power Requirements:
- DC 9V (six R14 (size C) batteries)
- DC IN 9V jack (accepts Sony AC power adaptor (supplied))
- Power consumption (supplied AC power adaptor):
- AEP Model: 10W
- UK Model: 10W
- AEP Model: 220V AC, 50Hz
- UK Model: 240V AC, 50Hz
- DCC-127B car battery cord (optional) for use with 12V car battery
- Battery Life (approximate hours):
- Battery Type: Sony SUM-2 (NB)
- FM recording: 16 hours
- Sony AM2 alkaline: Approx. 27 hours
- Battery Type: R14 (size C)
- Dimensions (W/H/D):
- 390 x 130 x 130mm (15 3/8 x 5 1/8 x 5 1/8 inches) incl. projecting parts and controls
- Weight:
- Approx. 2.65 kg (5 lb 13oz) incl. batteries
- Accessory Supplied:
Usage Features:
The CFS-903L is designed for ease of use. The front panel features clearly labeled controls for function selection, tuning, volume, and tone. The tape operation buttons are intuitively arranged for quick access to playback and recording functions. The OPR/BATT indicator provides a visual cue for the unit's operational status and helps monitor battery life, preventing unexpected power loss during use. The inclusion of a PHONES jack allows for private listening, making the device suitable for various environments without disturbing others. Its portable design, supported by battery power, allows users to enjoy audio entertainment on the go. The option to use a car battery cord further enhances its versatility for travel.
Maintenance Features:
The service manual provides detailed instructions for the maintenance and repair of the CFS-903L.
- Disassembly: Step-by-step procedures are outlined for disassembling the unit, including removing the front cabinet, handle assembly, tuning knob, and dial pointer. This facilitates access to internal components for inspection and repair.
- Adjustments: The manual includes sections for mechanical and electrical adjustments.
- Mechanical Adjustments: Instructions cover tape recorder section adjustments such as head azimuth, tape speed, and wow/flutter. These ensure optimal tape playback and recording quality.
- Electrical Adjustments: Detailed procedures are provided for radio section adjustments, including FM, AM, MW, LW, and SW frequency coverage, as well as VCO (Voltage Controlled Oscillator) adjustments. These are crucial for accurate radio reception across all bands.
- Diagrams: Comprehensive diagrams are included:
- Semiconductor Lead Layouts: Aids in identifying and correctly placing semiconductor components.
- Schematic Diagrams: Separate diagrams for the tuner and audio sections provide a complete circuit overview, essential for troubleshooting and component replacement.
- Printed Wiring Boards: Visual representations of the printed circuit boards help in locating components and tracing connections.
- Exploded Views: Detailed exploded diagrams illustrate the assembly of the unit, with numbered parts corresponding to a parts list. This is invaluable for identifying and ordering replacement parts.
- Electrical Parts List: A comprehensive list of all electrical components, including part numbers, descriptions, and specifications, is provided. This ensures that correct replacement parts are used during repairs.
- Safety-Related Component Warning: The manual highlights safety-related components with specific markings on diagrams and parts lists. It emphasizes the importance of replacing these components only with Sony parts to ensure safe operation.
- General Maintenance Advice: The manual includes important notes such as "Do Not Immerse in Water" and instructions for cleaning the cabinet and controls. It advises against using alcohol, benzine, thinner, or abrasive cleaning agents to prevent damage to the finish. For stubborn dirt, a mild detergent solution is recommended. The manual also warns against using the unit near water to avoid electric shock.
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