The Sony CFS-204 is a portable radio cassette-corder designed for both playback and recording of audio, featuring an integrated AM/FM radio tuner. This AEP (Audio European Product) model, with an Italian variant also available, is a versatile device for personal audio entertainment and recording.
Function Description:
The CFS-204 operates as a radio receiver for both FM and AM bands, allowing users to tune into their favorite stations. It also functions as a cassette player and recorder, supporting standard compact cassettes. The recording system is a 4-track, 2-channel stereo, ensuring a good quality stereo recording and playback experience. The device is equipped with a telescopic antenna for FM reception and a ferrite-rod antenna for AM reception, optimizing signal capture for different frequency bands.
For audio output, the CFS-204 features two full-range 10cm (4 inches) speakers, providing a stereo sound experience. Additionally, it includes a stereo minijack for headphones, allowing for private listening with an impedance range of 16-68 ohms. This makes it suitable for use with a wide variety of headphones.
The control interface includes a function switch to select between Tape, Radio, and Off modes, as well as separate switches for FM mode (Stereo/Mono/ISS) and power. Recording is initiated via a dedicated REC button, and playback controls include Pause, FF (Fast Forward), REW (Rewind), and Play buttons. Tuning is managed by a rotary knob, and separate rotary controls are provided for Volume and Tone adjustment.
Important Technical Specifications:
- Frequency Range:
- FM: 87.6-107MHz (AEP model), 87.5-108MHz (Italian model)
- AM: 531-1,602kHz (AEP model), 526.5-1,606.5kHz (Italian model)
- Recording System: 4-track, 2-channel stereo
- Frequency Response: 80Hz-8,000Hz
- Speakers: Full-range: 10cm (4 inches) diameter x 2
- Power Output: 2.3W + 2.3W (at 10% harmonic distortion) at DC operation
- Headphones Jack: Stereo minijack, 16-68 ohm impedance
- Power Requirements:
- AC: 220V, 50Hz
- DC: 9V (six R14, or size C, batteries)
- Power Consumption: 14W
- Battery Life (Sony SUM-2 (NS) / Sony AM2 alkaline):
- FM recording: Approximately 4 hours / Approximately 8 hours
- Dimensions (w/h/d): 460 x 145 x 160mm (18 1/8 x 5 3/4 x 6 3/8 inches), including projecting parts and controls
- Weight: Approximately 2.4kg (5 lb 5 oz), including batteries
- Accessory Supplied: AC power cord (1)
Usage Features:
The CFS-204 is designed for user-friendly operation. The clear labeling of controls and the logical layout of buttons make it easy to switch between functions, adjust volume and tone, and control cassette operations. The inclusion of both AC and DC power options provides flexibility, allowing the device to be used at home or on the go with batteries. The long battery life, particularly with AM2 alkaline batteries, supports extended portable use for FM recording. The dial pointer setting procedure ensures accurate tuning, guiding the user to set the pointer to the center of scratched lines for precise frequency selection.
Maintenance Features:
The service manual provides detailed instructions for disassembly and adjustments, which are crucial for maintaining the device's performance over time.
- Disassembly: The manual outlines the step-by-step procedure for removing the cassette holder and setting the dial pointer, which are fundamental for accessing internal components for service.
- Mechanical Adjustments:
- Cleaning: Regular cleaning of critical parts such as the record/playback head, pinch roller, erase head, capstan, rubber belts, and idlers with a denatured-alcohol-moistened swab is recommended to ensure optimal audio quality and tape transport.
- Demagnetization: Demagnetizing the record/playback head with a head demagnetizer is advised to prevent tape degradation and maintain sound fidelity. A specific caution is given not to bring the demagnetizer close to the erase head.
- Torque Measurement: The manual specifies procedures for measuring forward, forward back tension, fast forward, and rewind torque using a torque meter (CQ-102C, CQ-201B). This helps ensure the tape transport mechanism operates within specified ranges (e.g., 20-60g.cm for forward torque).
- Tape Tension Measurement: Instructions for measuring forward and reverse tape tension using a tape tension meter (CQ-403A, CQ-403R) are provided, with specified readings (e.g., more than 70g for forward).
- Electrical Adjustments:
- Tape Speed Adjustment: A detailed procedure for adjusting tape speed during playback is included, using a test tape (WS-48A) and a speed checker (LFM-30) or digital frequency counter. The adjustment value is specified as ±2.5% for the speed checker or 2,925 to 3,075Hz for the frequency counter. The adjustment location is inside the motor.
- Radio Section Adjustments: Comprehensive instructions for adjusting FM and AM frequency coverage, tracking, and AM IF are provided. These adjustments involve using an RF signal generator, VTVM, and tuning specific coils (L1, L2, L3, L4) and trimmer capacitors (CT1, CT2, CT3, CT4) to achieve maximum VTVM readings at specified frequencies. The procedure emphasizes repeating adjustments and performing final adjustments with trimmer capacitors.
- VCO Adjustment: A dedicated procedure for adjusting the VCO (Voltage Controlled Oscillator) using an FM RF signal generator and a frequency counter is outlined, ensuring the correct frequency reading (76kHz ± 500Hz) at 98MHz.
- Safety-Related Components: The manual highlights components identified with a "MARK A" or dotted line with "MARK A" on schematic diagrams and parts lists as critical for safe operation. It explicitly states that these components must be replaced with genuine Sony parts with the specified part numbers.
- Power Supply: Adjustments should be performed with the rated power supply voltage (9V DC) unless otherwise noted.
- Tooling: The use of a non-magnetized screwdriver for adjustments is recommended to prevent interference.
- Locking Compound: After adjustments, applying suitable locking compound to the adjusted parts is advised to secure their settings.
Overall, the Sony CFS-204 is a robust and serviceable radio cassette-corder, designed with both user experience and long-term maintenance in mind.
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