Sony WM-FS421 User Manual

WM-FS421
E Model SERVICE MANUAL
RADIO CASSETTE PLAYER
Sony Corporation
Personal Audio Company
Shinagawa Tec Service Manual Production Group
9-873-121-11
2001D1600-1
© 2001.4
Ver 1.0 2001. 04
SPECIFICATIONS
Model Name Using Similar Mechanism NEW
Tape Transport Mechanism Type MF-WMFS421-114
• Frequency range
FM: 87.5 - 108 MHz
AM: 530 - 1 710 kHz (North, Central and South America)
531 - 1 602 kHz (Other countries)
• Power requirements
3 V DC batteries R6 (size AA) × 2
• Dimensions (w/h/d)
Approx. 107.3 × 123.3 × 51.5 mm (4
1
⁄
4
× 4
7
⁄
8
× 2
1
⁄
8
inches),
excluding projecting parts and controls
• Mass
Approx. 282 g (10.0 oz) (main unit only)
• Supplied accessories
Stereo headphones or earphones (1)
Belt clip (1)
Design and specifications are subject to change without notice.
Battery life (approximate hours) (JEITA*)
Tape Radio
playback reception
Sony alkaline LR6 (SG)** 32 40
Sony R6P (SR) 9 14
* Measured value by the standard of JEITA (Japan Electronics
and Information Technology Industries Association). (Using
a Sony HF series cassette tape)
**When using Sony LR6 (SG) “STAMINA” alkaline dry
batteries (produced in Japan).
Note
•The battery life may be shorter depending on the
operating condition, the surrounding temperature
and battery type.

Sony WM-FS421 Specifications

General

Type	Cassette Player
Brand	Sony
Model	WM-FS421
Tuner	FM/AM
Noise Reduction	Dolby B
Power Supply	2 x AA batteries
Dimensions	135 x 90 x 38 mm
Weight	200 g
Signal-to-Noise Ratio	50 dB
Play speed	4.8 cm/s
Playback Speed	1.875 ips

Summary

Specifications

Section 2 Service Note

Section 3 Disassembly

3-1. Main Assy

3-3. Main Board and Mechanism Deck

Guidance on detaching the main board and mechanism deck, involving solder removal and screws.

3-5. Head, Magnetic (HP701)

Section 4 Mechanical Adjustment

Section 5 Electrical Adjustment

Tape Section

Specifies test tape, signal, and usage for tape speed adjustment procedures.

FM VCO Adjustment

Procedure for adjusting the FM Voltage-Controlled Oscillator (VCO) using a frequency counter.

AM IF Adjustment

AM Frequency Coverage Adjustment

Steps for adjusting AM frequency coverage using a digital voltmeter.

AM Tracking Adjustment

FM Tracking Adjustment

Section 6 Diagrams

6-1. IC Block Diagrams

6-2. Block Diagram

Overall system block diagram illustrating signal paths and major component interconnections.

6-4. Schematic Diagram

Detailed electronic schematic showing circuit connections, component values, and voltage points.

6-5. IC Pin Function Description

Section 7 Exploded Views

Section 8 Electrical Parts List