SANYO 18H-815 Portable Radio Service Manual
Comprehensive service manual for the SANYO 18H-815 18-transistor, 6-band portable radio, including technical specifications, alignment procedures, circuit board diagrams, and a complete parts list.
Table of contents
Quick guide from the manual
This service manual provides technical documentation for the SANYO 18H-815 portable radio. It is intended for qualified service personnel to perform maintenance, alignment, and repairs. The document contains detailed specifications, alignment procedures for AM and FM bands, circuit board layouts, and a comprehensive parts list.
Specifications
The SANYO 18H-815 is an 18-transistor, 6-band portable radio.
- Frequency Range: FM (87-108 MC), SW1 (2.3-7.3 MC), SW2 (8.0-22.0 MC), 49m (5.95-7.3 MC), MW (520-1605 KC), LW (150-350 KC).
- Intermediate Frequency: FM (10.7 MC), AM (455 KC).
- Output Power: Maximum 3,000 mW, Undistorted 2,000 mW.
- Power Supply: 12V (8 x UM-1 size D batteries) or AC adaptor (D12-815).
- Speaker: 5x7 inch oval type, 4 ohm voice coil.
Alignment Procedures
The manual details specific alignment sequences for AM and FM bands. These procedures require a signal generator, sweep generator, and oscilloscope connected to specific test points (TP-1, TP-2) as indicated in the alignment tables. Adjustments involve tuning specific coils (T-series) and trimmers (Ct-series) to achieve maximum output or optimal response curves.
Adjustment of Semi-Fixed Resistors
Specific internal adjustments are required for optimal performance:
- R88 (10K ohms): Adjust for equal clipping on both tops and bottoms of waveforms in the first audio stage.
- R42 (100K ohms): Set to MW reception at 1000KC; adjust for 400µA current through the collector of Tr9.
- R12 (100K ohms): Set to FM reception; adjust for 400µA current through the collector of Tr4.
Circuit and Block Diagrams
The manual includes a detailed block diagram showing the signal path from the antenna through the RF/IF stages to the audio amplifier and speaker. A full schematic drawing is provided, detailing all transistor connections, resistors, capacitors, and coil configurations. The circuit board diagram illustrates the physical layout of components for troubleshooting and repair.
Parts List
A complete parts list is included, categorizing components by housing, coils/transformers, controls, switches, miscellaneous items, diodes, transistors, fixed resistors, and capacitors. Each part is listed with its schematic location and description.
Practical help
Common problems
Adjust semi-fixed resistors R88, R42, or R12 as specified in the 'Adjustment of Semi-Fixed Resistors' section.
Perform AM or FM alignment using a signal generator and oscilloscope to tune the corresponding I.F.T. coils and trimmers.
Before use
- Ensure 8 fresh UM-1 (size D) batteries are installed correctly or use the D12-815 AC adaptor.
- Verify the speaker impedance is 4 ohms.
- Check that the antenna is fully extended for optimal reception.
- Ensure the band selector is set to the desired frequency range.
Specs in practice
- Intermediate Frequency (IF)
- The frequency to which the radio's internal stages are tuned for processing (10.7 MC for FM, 455 KC for AM).
- Current Drain
- Power consumption ranging from 30 mA (no signal) to 420 mA (maximum volume).
Model compatibility
- Designed for use with SANYO D12-815 AC adaptor.
- Speaker must have 4 ohm voice coil impedance.
Manual page author
Michael Turner
Technical manual editor
Reviews PDF manuals for structure, safety notes, and practical product details so readers can find the right information quickly.