Sony CRF-5090 GEP Model
General Export Model Service Manual
Specifications
| Circuit System | 13-transistor, 10-diode superheterodyne, 7-transistors for auxiliary circuit |
| Frequency Coverage | AIR: 108-136 MHz, FM: 87.5-108 MHz, LW: 150-400 kHz, MW: 530-1,605 kHz, SW1: 1.6-3.5 MHz, SW2: 3.5-9.0 MHz, SW3: 9.0-14.0 MHz, SW4: 14-21 MHz, SW5: 21-26 MHz |
| Intermediate Frequency | FM/AIR: 10.7 MHz, LW/MW/SW: 455 kHz |
| Antenna System | FM/AIR: Telescopic or external (75 Ω). LW/MW: Built-in ferrite bar or external (high impedance). SW: Telescopic or external (75 Ω). |
| Sensitivity (at 50 mW output, S/N 6 dB) | AIR: 0.9 µV, FM: 0.7 µV, LW: 63 µV/m, MW: 24 µV/m, SW1: 1.2 µV, SW2: 1 µV, SW3: 1 µV, SW4: 1.2 µV, SW5: 1.3 µV |
| Selectivity (at ±10 kHz off-resonance) | 35 dB at 1,400 kHz |
| Power Output (at 10% distortion) | Maximum: 2.7 W |
| Current Drain (at zero signal) | FM: 40 mA, MW: 35 mA |
| Power Requirement | AC: 100/120/220/240 VAC, 50/60 Hz; DC: Eight 'D' size batteries or 12V car battery (via cord). |
| Speaker | 10 cm x 15 cm (4" x 6"), 8 Ω |
| Dimensions | 340 mm (W) x 230 mm (H) x 160 mm (D) (13 3/8" x 9 1/16" x 6 5/16") |
| Weight | 6.6 kg (14 lb 9 oz) with batteries |
Outline
The Sony CRF-5090 is a GEP (General Export) Model portable radio receiver. It features a 13-transistor, 10-diode superheterodyne circuit with additional transistors for auxiliary circuits. The unit covers AM (LW, MW) and FM broadcast bands, as well as multiple shortwave bands (SW1-SW5) and the AIR band (108-136 MHz).
External View: The front panel includes the dial scale for tuning, band selector, tuning knob, fine tuning knob, power switch, and a light button. The telescopic antenna is located on the top.
Block Diagram: The block diagram illustrates the signal flow from the antenna through RF amplification, mixing, IF amplification, detection, and audio amplification to the speaker. It shows separate paths for FM/AIR and LW/MW/SW signals, with AGC (Automatic Gain Control) and BFO (Beat Frequency Oscillator) circuits integrated.
Disassembly and Reassembly
This section details the procedures for taking apart and reassembling the CRF-5090. Key steps include:
- Front Panel Removal: Involves removing screws and sliding the front cover off.
- Chassis Removal: Requires disconnecting speaker leads and removing various screws to release the chassis from the cabinet.
- FM Front End Removal/Reassembly: Specific instructions for accessing and handling the FM front-end components.
- Dial Scale Reassembly: Guidance on correctly reassembling the dial scale and associated mechanisms.
- Circuit Board Removal: Steps for removing the main circuit boards, including disconnecting connectors and unscrewing mounting screws.
- Dial Cord Stringing: Detailed instructions and diagrams for properly stringing the dial cords that operate the tuning mechanism. This involves specific lengths and routing around pulleys and drums.
Circuit Adjustments
This section outlines the necessary test equipment, tools, and preparation steps for calibrating the receiver. It covers adjustments for various bands and functions:
- FM I-F Alignment: Adjustments for the Intermediate Frequency (IF) stages for FM reception, including specific alignment points (IFT F-4, F-1, F-2, F-3) and required signal generator settings.
- AM I-F Alignment: Procedures for aligning the AM Intermediate Frequency stages, noting that the ceramic filter is factory preset.
- BFO OSC Coil Adjustment: Tuning the Beat Frequency Oscillator coil for proper reception of single-sideband or CW signals.
- Frequency Coverage and Tracking Adjustment: This is a critical section covering the calibration of the receiver's tuning across all bands (FM, AIR, LW, MW, SW1-SW5). It involves adjusting various oscillator and antenna coils and trimmers to ensure accurate frequency reception and tracking across the dial. Detailed tables specify the test frequencies, signal generator settings, receiver pointer positions, and the specific components (coils/trimmers) to adjust for each band and function (coverage/tracking).
Diagrams: Schematic diagrams and mounting diagrams are provided to illustrate the internal circuitry and component placement, aiding in troubleshooting and repair.
Exploded View and Packing
Exploded views are provided showing the physical layout of components for disassembly and reassembly. These diagrams help in identifying parts and understanding how the unit is constructed. Packing instructions are also included.
Electrical Parts List
A comprehensive list of all electrical components used in the Sony CRF-5090 is provided, including reference numbers, part numbers, descriptions (e.g., ceramic capacitors, electrolytic capacitors, resistors, transistors, ICs), and specifications. This list is essential for ordering replacement parts.
(Note: Due to the extensive nature of the parts list, individual component details are not fully transcribed here to maintain conciseness. The original document contains detailed listings for capacitors, resistors, transistors, and miscellaneous components.)
Miscellaneous Components
This section lists various other parts such as antennas, speakers, jacks, switches, lamps, connectors, and circuit boards, along with their part numbers and descriptions.
