This document is a service manual for the Sony CFD-21 and CFD-20/30 models, which are CD radio cassette-corders. The CFD-21 is similar to the earlier CFD-20, with the CFD-20/30 manual providing information not contained in the CFD-21 manual. The CFD-20/30 is a white-type US model, while the CFD-20 is a US model and the CFD-30 is an E model.
Function Description:
The Sony CFD-21 and CFD-20/30 are integrated audio systems designed for playing CDs, listening to the radio, and recording/playing cassette tapes. They feature a CD player, an AM/FM radio tuner, and a cassette deck. The device allows for recording from the radio or CD to cassette tape, as well as playing back pre-recorded tapes. It includes various controls for playback, recording, tuning, and volume adjustment.
Important Technical Specifications (CFD-20/30):
- Audio Power Specifications:
- POWER OUTPUT AND TOTAL HARMONIC DISTORTION: With 3.0-ohm loads, both channels driven from 150-15,000 Hz; rated 2.3 W per channel minimum RMS power, with no more than 10% total harmonic distortion in AC operation.
- Other Specifications:
- CD Player Section:
- System: Compact disc digital audio system
- Laser diode properties: Material GaAlAs, Wavelength 780 nm, Emission duration Continuous, Laser output less than 44.6 µW. This output is the value measured at a distance of about 200 mm from the objective lens surface on the optical pick-up block.
- Frequency response:
- CD: 20-20,000 Hz
- Radio: Below measurable limit
- Wow and flutter: Below measurable limit
- Radio Section:
- Frequency range: FM: 87.6-108 MHz, AM: 530-1,710 kHz
- Antennas: FM: Telescopic antenna, AM: Built-in ferrite bar antenna
- Tape recorder section and general:
- Recording system: 4-track 2-channel stereo
- Frequency response: 70-10,000 Hz (with TYPE I (NORMAL) cassette)
- Speaker: Full range speakers, 10 cm dia., cone type
- Power output (for European model): 4.6W (2.3 W + 2.3 W) (at 3.0 ohms, 10% harmonic distortion)
- Input: Mixing microphone input jack (minijack), Sensitivity 0.9 mV for low impedance microphone
- Output:
- Headphones jack (stereo minijack)
- For 8-300 ohms impedance headphones
- Power requirements: 120V AC, 60 Hz, DC 9V, 6 size D (R20) batteries
- Power consumption: 25 W
- Battery life (approx. hours):
- FM recording: SUM-1 (NS) approx. 9, Alkaline AM-1 (N) approx. 16.5
- Tape playing: SUM-1 (NS) approx. 6, Alkaline AM-1 (N) approx. 11
- CD playing: SUM-1 (NS) approx. 2.5, Alkaline AM-1 (N) approx. 4.5
- Dimensions: Approx. 410 x 170 x 226 mm (w/h/d) (Approx. 16 1/4 x 6 3/4 x 9 inches) incl. projecting parts and controls
- Weight: Approx. 4.0 kg (8 lb 13 oz) without batteries (Approx. 9 lb 5 oz)
- Supplied accessory: AC power cord (1)
Usage Features:
The device offers intuitive controls for its various functions.
- CD Playback: Users can play audio CDs, with controls for play, pause, stop, fast forward, rewind, and track selection (AMS/SEARCH). The display shows information about the current track and time. Features like "Program Play," "Repeat Play," and "Shuffle Play" are available for customized listening.
- Radio Tuning: The device includes a dial scale for tuning into FM and AM radio stations. A "FM STEREO indicator" lights up when a stereo FM broadcast is received.
- Cassette Operation: Standard tape operation buttons are present: PAUSE, STOP/EJECT, FF (fast forward), REW (rewind), PLAY, and REC (record). The device supports recording from CD or radio.
- General Controls: Volume control, tone control, and a BASS BOOST switch are available to adjust the audio output. An AC IN jack allows for mains power, while the device can also operate on batteries for portability.
- Input/Output: A MIXING MIC jack allows for microphone input, and a headphone jack is provided for private listening.
Maintenance Features:
The service manual provides detailed instructions for safety checks, leakage tests, and various adjustments to ensure optimal performance.
- Safety Check-Out: Before returning the original service problem, a safety check must be performed. This includes checking the interlock terminals, metal trim, "metallized" knobs, screws, and all other exposed metal parts for AC leakage.
- Leakage Test: The AC leakage from any exposed metal part to earth ground and from all exposed metal parts to any exposed metal part having a return to chassis must not exceed 0.5 mA (500 microampers). Methods for measuring leakage current are provided, including using a commercial leakage tester or an AC milliammeter.
- Laser Diode and Focus Search Operation Check: Instructions are given to make the function switch to CD position with no disc inserted, open the lid for CD, turn on S810, press PLAY, confirm laser diode emission, and observe objective lens movement.
- Chuck Plate Jig on Repairing: For repairing the CD section, playing a disc without the CD lid requires using a Chuck Plate Jig (X-4918-255-1). Instructions for removing the chuck plate are also provided.
- Mechanical Adjustment: This section covers tape recorder section adjustments, including tape tension measurement and adjustment of the record/playback head azimuth.
- Electrical Adjustment: Detailed procedures for adjusting the radio section (FM and AM frequency coverage, tracking, and IF), CD section (VCO adjustment, E.F. balance, focus bias, focus/tracking gain), and record bias are provided. These adjustments often require specialized equipment like oscilloscopes, frequency counters, and signal generators.
- Exploded Views and Parts Lists: The manual includes exploded diagrams of the front cabinet, CD section, and mechanism decks (for both CFD-20 and CFD-30), along with comprehensive parts lists. This aids in identifying and replacing components.
- Electrical Parts List: Detailed lists of electrical components, including capacitors, resistors, transistors, diodes, and ICs, are provided for various sections like Audio, Battery, CD Control, CD Leaf, CD Main, Power, REC SW (RVS), REC SW (TUNER), and Tuner.
- Safety-Related Component Warning: Components identified by a mark or dotted line with a mark are critical for safety. These parts should only be replaced with Sony parts with the specified part numbers.
- Note on Stocked Items: Items marked with "*" are not stocked since they are seldom required for routine service. Some delay should be anticipated when ordering these items.
This manual serves as a comprehensive guide for servicing and maintaining the Sony CFD-21 and CFD-20/30 CD radio cassette-corders, ensuring proper function and safety.
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