The provided document is a service manual for the Panasonic Mini Cassette Recorder RQ-355 (Brown), a voice-activated mini cassette recorder with tape speed control. This manual is intended for service in European areas (excluding the UK), Asia, Latin America, Middle East, Africa, and Australia.
Function Description
The Panasonic RQ-355 is a portable mini cassette recorder designed for recording and playback of audio, featuring voice activation and variable tape speed control. It is equipped with a built-in microphone for convenient recording and a monitor jack for private listening. The device supports both recording and playback in a 2-track monaural system.
Important Technical Specifications
Power Requirement:
- Battery: 3V (Two R6 (UM-3) size dry batteries).
- AC (D areas): With optional AC adaptor RP-31.
- AC (NA areas): With optional AC adaptor RP-34.
Power Output:
Frequency Range:
Motor:
- Electrical governor motor
Wow and Flutter:
Tape Speed:
Track System:
- 2-track monaural recording and playback
Fast Forward and Rewind Time:
- Approximately 140 seconds with C-60 cassette tape.
Jacks:
- Mic: Sensitivity 0.25mV / Applicable microphone impedance 200Ω-600Ω.
- DC-in: 3V.
- Monitor: 8Ω.
Speaker:
Dimensions:
- 85 mm (W) × 134 mm (H) × 33 mm (D)
Weight:
Standard Recording Input Level (1kHz):
Overall Frequency Response:
- 250 Hz: -3dB ± 5dB
- 1 kHz: 0dB
- 6 kHz: -3dB ± 6dB
Playback Output Level (using QZZCFM test tape, 315Hz, 0dB):
Pressure of Pressure Roller:
Takeup Tension (using QZZRKCT cassette torque meter):
Usage Features
The RQ-355 offers a range of controls and components for intuitive operation:
Top Panel Controls:
- Battery Check Lamp [BATT]: Indicates battery status.
- Recording Indicator [REC]: Lights up during recording.
- Built-in Microphone: For direct audio capture.
- Stop/Eject Button [STOP/A EJECT]: Stops operation and ejects the cassette.
- Record Button [REC]: Initiates recording.
- Play Button [◄ PLAY]: Starts playback.
- Rewind/Review Button [►► REW/REV]: Rewinds the tape and allows for review during playback.
- Fast Forward/Cue Button [FF/CUE◄◄]: Fast forwards the tape and allows for cueing during playback.
- Voice Activation Switch [VOICE ACTIVATION (OFF/ON)]: Enables or disables voice-activated recording.
- Hand Strap: For portability.
Side Panel Controls/Jacks:
- Pause Control [II PAUSE (OFF LOCK)]: Temporarily pauses recording or playback.
- Cassette Compartment Cover: Protects the cassette.
- Monitor Jack [MONITOR (8Ω)]: For connecting headphones or an external monitor.
- Volume Control [() VOLUME/VAS LEVEL]: Adjusts playback volume and Voice Activation System (VAS) level.
- Tape Counter and Reset Button: Tracks tape position and resets the counter.
- Microphone Jack [MIC]: For connecting an external microphone.
- Remote Control Connection Jack [REMOTE]: For connecting a remote control.
- External Power Supply Input Jack [DC IN 3V ()]: For connecting an AC adaptor.
- Battery Compartment [OPEN BATT]: Houses the dry cell batteries.
- Tape Speed Adjustment Control [()]: Allows fine-tuning of tape speed.
- Tape Speed Control Switch [VARIABLE SPEED (OFF ON)]: Toggles variable tape speed control on or off.
- Sensitivity Switch for Built-in Microphone [MIC SENS (HIGH-LOW)]: Adjusts the sensitivity of the built-in microphone.
Maintenance Features
The service manual provides detailed instructions for disassembly, reassembly, measurement, and adjustment, crucial for maintaining the device's performance.
Disassembly Instructions:
- Step-by-step guide for removing the bottom case, main case, main circuit board, and motor governor circuit board.
- Specific instructions for removing the intermediate plate assembly, including handling screws, springs, and various components like the lower plate assembly, switch angle, FF/REW button spring, erase safety lever spring, flywheel assembly, playback rod spring, and counter belt.
- Emphasis on careful handling to prevent components from popping out during disassembly.
Precautions in Disassembly and Reassembly:
- A critical note advises temporarily tightening the REW button assembly (M64) with a screw (G9) when checking operation after removing the mechanism unit from the bottom case, as the button can easily come off.
Measurement and Adjustment Methods:
- General Notes: Stresses the importance of clean heads, capstan, and pressure roller, and specifies a judgeable room temperature of 20±5°C (68±9°F). Volume control should be set to 8, speed control to OFF, and voice operation to OFF unless otherwise specified.
- Tape Speed Accuracy Adjustment:
- Condition: Playback mode.
- Equipment: Digital electronic counter or frequency counter, test tape (QZZCWAT), and an 8Ω resistor.
- Procedure: Connect equipment as shown in the diagram, playback the test tape (3,000 Hz), measure the frequency at the middle section of the tape, and calculate the accuracy.
- Standard Value: ±2.5% (f = 2,925-3,075 Hz).
- Adjustment: If the measured value is outside the standard, adjust VR201 on the circuit board to achieve 3,000 Hz.
- Adjusting the Governor Circuit (µ adjustment):
- Condition: Playback mode.
- Checks after Motor Replacement: After replacing the motor, playback the test tape (QZZCWAT) and listen for sound quality. If the sound vibrates or fluctuates, change resistor R202 to 1.5 ohms (ERD10TJ1R5). Verify that the reproduced sound does not fluctuate.
Electrical Parts List:
- Comprehensive lists of resistors (carbon, metal-oxide, metal-film, fuse type metallic, solid, cement, chip), capacitors (ceramic, polyester film, polypropylene, electrolytic, non-polar electrolytic, polystyrene, tantalum, chip), transistors, diodes & rectifiers, integrated circuits, switches, variable resistors, and jacks, complete with part numbers and descriptions.
Circuit Boards and Wiring Connection Diagram:
- Detailed diagrams showing the layout of components on the main circuit board and motor governor circuit board, including voltage values at various points under no signal condition and playback mode (volume max).
- Specific voltage values for record mode and voice operation (ON) mode are also provided.
- Clear labeling of components and connections, including chip parts.
- A note indicates that the circuit diagram may be modified with new technology.
Mechanical Parts Location:
- Exploded views of the mechanism from both front and rear perspectives, detailing the location of all mechanical parts.
- Instructions for applying Molycoat EM20L grease and Rocol Paste to specific areas during mechanism part changes.
- A comprehensive replacement parts list for all mechanical components, including screws, springs, gears, levers, and assemblies.
Cabinet Parts Location:
- Exploded view of the cabinet, showing the location of external components like the battery lid, various switches, jacks, and the main circuit board.
- A replacement parts list for cabinet components, including the cabinet assembly, battery terminals, and various knobs and covers.
Correction (Supplement-1):
- A supplement updates the replacement parts list for the Monitor Jack (J2) and Jack Plate Assembly (G12), indicating a change in the part number for J2 from QJA0196H to being integrated into the QEJA0028 Jack Plate Assembly.
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