Sony TC-WR681 User Manual

– 1 –
Model Name Using Similar
Mechanism
NEW
Tape Transport DECK A TCM-230ASR1
Mechanism Type DECK B TCM-230ASR2
SERVICE MANUAL
US Model
TC-WE425/WR681
Canadian Model
TC-WE425
AEP Model
TC-WE525/WR681
UK Model
TC-WE525
E Model
Australian Model
TC-WE425/WR681
Chinese Model
TC-WE425
TC-WE425/WE525/
WR681
STEREO CASSETTE DECK
MICROFILM
System
Recording system
4-track 2-channel stereo
Fast-winding time (approx.)
100 sec. (with Sony C-60 cassette)
Bias
AC bias
Signal-to-noise ratio (at peak level and weighted with Dolby NR off)
Type I tape, Sony Type I (NORMAL): 55 dB
Type II tape, Sony Type II (HIGH): 57 dB
Type IV tape, Sony Type IV (METAL): 58 dB
S/N ratio improvement (approximate values)
With Dolby B NR on: 5 dB at 1 kHz, 10 dB at 5 kHz
With Dolby C NR on: 15 dB at 500 Hz, 20 dB at 1 kHz
Harmonic distortion
0.4% (with Type I tape, Sony Type I (NORMAL):
160 nWb/m 315 Hz, 3rd H.D.)
1.8% (with Type IV tape, Sony Type IV (METAL):
250 nWb/m 315 Hz, 3rd H.D.)
SPECIFICATIONS
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Photo: TC-WE425
Dolby noise reduction extension manufactured under license
from Dolby Laboratories Licensing Corporation.
HX Pro originated by Bang & Olufsen. “DOLBY”, the double-D
symbol a and “HX PRO” are trademarks of Dolby Laboratories
Licensing Corporation.
Frequency response (Dolby NR off)
Tape type
Type I tape, Sony Type I 30-16,000 Hz (±3 dB, IEC),
(NORMAL) 20-17,000 Hz (±6 dB)
Type II tape, Sony Type II 30-17,000 Hz (±3 dB, IEC),
(HIGH) 20-18,000 Hz (±6 dB)
Type IV tape, Sony Type IV 30-19,000 Hz (±3 dB, IEC),
(METAL) 20-20,000 Hz (±6 dB),
Wow and flutter
± 0.15% W. Peak (IEC)
0.1% W. RMS (NAB)
± 0.2% W. Peak (DIN)

Sony TC-WR681 Specifications

General

Brand	Sony
Model	TC-WR681
Category	Cassette Player
Language	English

Summary

SPECIFICATIONS

System Specifications

Details system, recording, bias, and fast-winding specifications.

Performance Specifications

Covers signal-to-noise ratio, harmonic distortion, and frequency response.

Wow and Flutter

Specifies the wow and flutter characteristics.

SECTION 1 GENERAL

1-1. LOCATION OF CONTROLS

Details the physical layout and function of all controls on the unit.

SECTION 2 DISASSEMBLY

2-1. CASE AND FRONT PANEL

Instructions for removing the case and front panel assemblies.

2-4. MECHANISM DECK ASSY (DECK A/B)

Guide to removing the main mechanism deck assembly.

2-5. SWITCH BOARDS

Instructions for accessing and removing leaf switch and head relay boards.

SECTION 3 MECHANICAL ADJUSTMENTS

SECTION 4 ELECTRICAL ADJUSTMENTS

Record/Playback Head Azimuth Adjustment

Adjusting the head alignment for optimal playback and recording.

Tape Speed Adjustment

Calibrating the tape transport speed for accuracy.

Playback Level Adjustment

Setting the correct output signal level for playback.

SECTION 5 DIAGRAMS

5-1. IC PIN DESCRIPTION

Details the pin functions for integrated circuits used in the unit.

5-4. SCHEMATIC DIAGRAM - MAIN SECTION (1/3)

Part 1 of the main circuit schematic diagram.

5-11. PRINTED WIRING BOARD - DECK A SECTION

Printed wiring layout for Deck A.

5-13. PRINTED WIRING BOARD - DECK B SECTION

Printed wiring layout for Deck B.

SECTION 6 EXPLODED VIEWS

6-1. CASE SECTION

Exploded view of the unit's case and related parts.

6-3. CASSETTE HOLDER SECTION

Exploded view of the cassette holder mechanism.

6-5. TAPE MECHANISM SECTION

Exploded view of the tape transport mechanism.

SECTION 7 ELECTRICAL PARTS LIST