This document is a Service Manual for the Panasonic RX-C300 Portable Stereo Component System, a radio cassette player. It provides detailed specifications, disassembly instructions, alignment procedures, circuit diagrams, and parts lists for maintenance and repair.
Function Description
The Panasonic RX-C300 is a portable stereo component system that integrates a radio tuner, a cassette deck, and an amplifier with speakers. It is designed for both AC and battery operation, offering versatility for home and portable use. The system features a graphic equalizer for sound customization and a spectrum analyzer for visual representation of audio levels. The cassette deck supports stereo recording and playback, including features like Dolby Noise Reduction and a Blank Skip function for enhanced usability.
Important Technical Specifications
General:
- Power Requirement:
- AC: 110-115V / 115-127V / 200-220V / 230-250V, 50/60Hz (M...For U.S.A.)
- AC: 120V, 60Hz (C...For Canada)
- Battery: 15V (Ten "D" Size Flashlight Batteries, UM-1 or equivalent)
- Car battery: with optional car adaptor RP-9550
- Power Consumption: 60W (AC only)
- Power Output: 80W (MPO)
- Dimensions (Max. size, without handle, projecting parts and controls):
- System: 585mm (W) × 382mm (H) × 202mm (D) (23 1/16" × 15 1/16" × 7 15/16")
- Tuner Amplifier: 228mm (W) × 157mm (H) × 201mm (D) (9" × 6 3/16" × 7 15/16")
- Cassette Deck: 228mm (W) × 157mm (H) × 190mm (D) (9" × 6 3/16" × 7 1/2")
- Speaker: 182mm (W) × 311mm (H) × 190mm (D) (7 3/16" × 12 1/4" × 7 1/2")
- Weight: 10.8 kg (23 lb. 13 oz.) without batteries
Speaker:
- Woofer: 6 1/2" (16 cm), PM Dynamic Speaker (5Ω)
- Squawker: 2 1/2" (6.5 cm), PM Dynamic Speaker (5Ω)
- Tweeter: 1 1/2" × 2" (2.8 cm × 4.7 cm), Ceramic Speaker (1.4 kΩ)
Input:
- MIC: sensitivity 0.8 mV / applicable microphone impedance 200-600Ω, Ø3.5
- PHONO: sensitivity 5 mV / 47 kΩ over
- LINE IN/CD: sensitivity 200 mV / 47 kΩ over
- DC IN: 13.2 V
Output:
- LINE OUT: sensitivity 420 mV / 4.7 kΩ under
- EXT SP: 5-8Ω
- HEADPHONES: 32Ω, Ø3.5
- EXT ANTENNA and EARTH
Radio Section:
- Radio Frequency Range:
- FM: 88-108 MHz
- AM: 525-1610 kHz
- Intermediate Frequency:
- Sensitivity:
- FM: 2.5 µV / 50 mW output (-3 dB Limit sens.)
- AM: 71 µV/m / 50 mW output
Tape Deck Section:
- Frequency Response:
- 40-15,000 Hz (with normal tape)
- 40-16,000 Hz (with CrO2 tape)
- 40-16,000 Hz (with Metal tape)
- Recording System: AC bias, AC erase
- Tape Speed: 4.8 cm/s (1 7/8 ips)
- Track System: 4-track 2-channel stereo recording and playback
Usage Features
The RX-C300 offers several user-friendly features:
- Function Selector: Allows switching between different modes (Tuner, Cassette, Phono, Line In/CD).
- Band Selector: For selecting FM or AM radio bands.
- Tuning Control: For precise radio station tuning, aided by a tuning indicator.
- Volume and Balance Controls: For adjusting overall sound level and left/right channel balance.
- Graphic Equalizer Controls: Provides customizable sound profiles.
- Headphones Jack: For private listening, with a caution to avoid excessive volume levels.
- Spectrum Analyzer: A visual display of audio frequency levels, with a dedicated switch to turn it on/off.
- Cassette Deck Controls: Includes Eject, Playback (forward/reverse), Stop, Fast Forward/Rewind, Record Muting, and Record Standby.
- Reverse Mode Selector: For continuous playback in auto-reverse mode.
- Dolby Noise Reduction: Improves sound quality by reducing tape hiss.
- Blank Skip Function: Automatically skips unrecorded portions of a tape during playback, useful for navigating between selections. This function may not work correctly with some pre-recorded tapes, such as classical music with many low sound levels, in which case it can be turned off.
- Tape Selector: For optimizing recording/playback for different tape types (Normal, CrO2, Metal).
- Timer Standby Selector: Allows the system to be set for timer-activated operations.
- Microphone Jacks: For connecting external microphones for recording.
- Power Switch and Power/Battery Check Indicator: For turning the unit on/off and monitoring battery status.
- Rear Panel Connections: Includes external antenna terminals, Line In/CD input jacks, Phono input jacks with ground terminal, telescopic antenna, speaker terminals, battery compartment, DC input jack, AC socket, and a voltage selector (for U.S.A. only). Line Output Jacks are also available.
Maintenance Features
The service manual provides comprehensive information for maintenance and repair:
- Safety Precautions: Emphasizes the importance of using manufacturer-specified parts for safety-critical components and proper insulation resistance tests after servicing to prevent electric shock.
- Disassembly Instructions: Detailed step-by-step guide with figures for disassembling various components like the front cabinet, circuit boards, and mechanism.
- Measurements and Adjustments:
- Alignment Instruction: Guidelines for setting volume, equalizer, band switch, balance, mode switch, and power source voltage before attempting alignment.
- MW and SW Alignment: Procedures for adjusting AM-IF and MW-RF sections using signal generators and voltmeters/scopes.
- FM Alignment: Procedures for adjusting FM-IF and FM-RF sections.
- Separation Alignment: Instructions for adjusting the pilot signal for optimal stereo separation.
- Audio Adjustment: Procedures for adjusting azimuth, playback level, erase current, bias current, and overall gain.
- Spectrum Analyzer Adjustment: Instructions for adjusting limit voltage and total level indicator.
- Tape Speed Adjustment: Procedure for adjusting tape speed using a test tape and counter.
- Circuit Description: Provides an overview of the system's electronic circuits, including the spectrum analyzer, and details on ICs and their functions.
- Schematic Diagrams: Detailed circuit diagrams for the Tuner, Amplifier, and Cassette Deck sections, including voltage readings and test points.
- Circuit Board and Wiring Connection Diagrams: Visual layouts of the circuit boards with component locations and wiring connections.
- Electrical Parts List: Comprehensive list of all electrical components with their part numbers, descriptions, and specifications.
- Replacement Parts List: Specific list for mechanical parts.
- Cabinet Parts Location: Diagrams showing the location of various cabinet components.
- Parts Comparison Table: Highlights differences in parts between original RX-C300 (M) and RX-C300 (MZ) models, particularly concerning the joint cable connector and socket shapes, which were modified for improved performance. It advises replacing both the joint cable and socket pairs when servicing.
- Caution for External Measuring Devices: Instructions for connecting external measuring devices to output lines, including the use of electrolytic capacitors to cut direct current and ensuring independent connections for left and right channels.
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