Sanyo RD 4080 - User Manual

Need help?

Do you have a question about the Sanyo RD 4080 and is the answer not in the manual?

Overview

Function Description
Important Technical Specifications
Usage Features
Maintenance Features

The Sanyo Cassette Tape Deck, models RD 4080, RD 4080 UM, and RD 4080 Australia, is a stereo audio recording and playback device designed for use with chromium dioxide or normal cassette tapes. This service manual provides comprehensive details for its operation, maintenance, and adjustment.

Function Description

The primary function of this device is to record and play back audio on cassette tapes. It features an AC bias recording system and an AC erase system, ensuring high-quality audio capture and removal. The deck operates at a standard tape speed of 1-7/8 ips (4.75 cm/sec). It incorporates a Dolby Noise Reduction (N.R.) system, which can be toggled on or off, to minimize tape hiss and improve the signal-to-noise ratio during both recording and playback. The device includes various input and output terminals to connect with other audio components, such as microphones, line-level sources, and headphones. A meter is provided for monitoring audio levels, and controls for recording and playback are clearly marked.

Important Technical Specifications

Tape: Chromium dioxide or normal cassette tape Recording System: AC bias, 1/4 track stereo Erasing System: AC erase, 1/2 track Tape Speed: 1-7/8 ips. (4.75 cm/sec.) Rewind & Fast Forward Time: Approximately 90 seconds for a C-60 cassette. Wow & Flutter: 0.15% RMS, indicating stable tape movement. Bias Frequency: 67 - 73 KHz, optimized for recording quality. Distortion: Less than 1% (at 1 KHz, -60dB), ensuring clear audio reproduction. Frequency Response:

Normal tape: 30 - 13,000Hz
Chromium dioxide tape: 30 - 16,000Hz Signal to Noise Ratio:
Dolby N.R. OFF: 50dB
Dolby N.R. ON: 58dB, demonstrating the effectiveness of the noise reduction system.

Terminal Impedance:

Input:
- MIC: 10K ohms (0.25mV)
- LINE IN: 60K ohms (63mV)
- REC/PB: 10K ohms (1mV)
Output:
- LINE OUT: 5K ohms (500mV)
- REC/PB: 5K ohms (500mV)
- HEADPHONE: 8-10K ohm

Power Source:

RD4080: AC 120/200/220/240V 50/60Hz
RD4080UM: 110/125/220V 50/60 Hz
RD4080AUST.: 240V 50/60Hz

Dimensions: 15-1/4" (W) x 10" (D) x 4-3/8" (H) (386 x 256 x 111mm) Weight: Approximately 8 lbs. 2 ozs. (3.7Kg)

Usage Features

The Sanyo Cassette Tape Deck is designed for straightforward operation. It includes dedicated controls for recording and playback, as well as fast forward and rewind functions. The Dolby N.R. system can be engaged to enhance audio quality, particularly for recordings made on standard tapes. Input terminals are available for microphones and line-level audio sources, allowing for versatile recording options. Output terminals facilitate connection to external amplifiers, receivers, or headphones for monitoring and listening. The unit's power source is adaptable to various international voltage standards, making it suitable for different regions. The presence of a meter allows users to visually monitor audio input and output levels, aiding in optimal recording.

Maintenance Features

The service manual outlines several critical adjustments and maintenance procedures to ensure the optimal performance and longevity of the cassette tape deck.

Adjustment of Pinch Roller:

Set the unit to PLAY mode.
Apply a tension gauge to the pinch roller, measuring the force at the moment it separates from the capstan.
The gauge reading should ideally be more than 200 g. If not, the spring coil force needs adjustment (refer to exploded view No. 23). This ensures proper tape transport and minimizes wow and flutter.

Torque Adjustment:

Set the unit to PLAY, FAST FORWARD, or REWIND mode.
Measure the torque for each mode using a torque gauge.
- PLAY: 30-60 g/cm
- FAST FORWARD: 55-110 g/cm
- REWIND: 55-110 g/cm
If the torque values are outside the standard range, it is recommended to clean the drive belt, flywheel, motor pulley, take-up reel, idler, and rewind roller with a cotton swab soaked in alcohol. This helps restore proper tape tension and transport.

Auto Shut-Off Adjustment:

Set the unit to PLAY mode.
Apply a tension gauge to the sensor and measure the sensor pressure.
The sensor pressure should be between 30-50 g.
If the pressure is outside this range, adjust the spring coil (refer to exploded view No. 25). This ensures the auto shut-off mechanism functions correctly, protecting the tape and mechanism from damage.

General Adjustments (as detailed in the "Adjustment" section):

Head Azimuth: Adjust to obtain maximum 10kHz output for both L and R channels, ensuring optimal high-frequency response and stereo imaging.
Output Level: Adjust SVR101 & SVR201 to achieve an output of 580mV ±0.5dB at LINE OUT during playback, ensuring consistent signal levels.
Meter Calibration: Adjust SVR102 & SVR202 to ensure the meter reads +2VU point when the output is 580mV, providing accurate visual feedback of audio levels.
Bias (Provisional): Identify head base color marks and adjust for specific voltage levels (e.g., purple - 4mV, green - 4.5mV, black - 5mV, red - 5.5mV, blue - 6.5mV, brown - 7mV). This is crucial for optimizing recording quality for different tape types.
Bias (Rec/Play Frequency Response): Record and play back at the adjusted bias level. Re-adjust SVR801 & SVR802 to obtain a 10kHz output of +2 to +3dB, relative to 1kHz = 0dB. This fine-tunes the recording equalization for flat frequency response.
Output Level (Recording Monitor): Adjust SVR103 & SVR203 until the REC/PLAY output corresponds to the recording monitor output, ensuring accurate monitoring during recording.

The manual also includes a detailed parts list for various components, including packing materials, accessories, cabinet parts, chassis components, and electrical parts (capacitors, resistors, switches, transformers, transistors, diodes, etc.), which is essential for identifying and replacing faulty parts during repairs. Modification notices are also provided to document any changes or corrections to the service manual or parts list, ensuring that technicians have the most up-to-date information.