Technics RS-646DS-D

“ORDER NO. ARD-7706063C
Service Manual
Cassette Deck
RS-646DS-D
Portable High-Fidelity Stereo Cassette Deck with
Separate Bias/Equalizer and Mic Attenuator
RS-640U MECHANISM SERIES
Specifications (Catalog specifications for sales)
Power
requirement:
AC;
110/220V,
50/60
Hz
Input:
MIC;
sensitivity
0.25
mV/applicable
microphone
Power
consumption;
10
W
impedance
400Q~
10K
DC;
12V,
eight
R-20
size
dry
cell
batteries
INE;
sensitivity
60
mV/input
impedance
47
KQ
Motor:
1-DC
electronical
speed
control
motor
DIN;
sensitivity
16
mV/input
impedance
2.7
KQ
Track
system:
4-track
2-channel
stereo
recording
and
playback
Output:
LINE;
output
level
420
mV/load
impedance
50
K2
Tape
speed:
4.8cm/s
over
Battery
life:
Approx.
32
hours
with
alkaline
batteries
DIN;
output
level
420
mV/output
impedance
1
KQ
Wow
and
flutter:
0.1%
(WRMS),
£0.2%
(DIN)
HEADPHONE
;
output
level
65
mV/load
Frequency
response:
CrOz
tape;
50~14,000Hz
+3dB
impedance
82
45
~
14,000
Hz
(DIN)
Monitor
speaker;
output
power 0.8
W
(monaural)
Normal
tape;
50~14,000Hz
+3dB
Head:
2-head
system
45
~14,000Hz
(DIN)
1-super
permalloy
head
for
record/playback
Signal-to-noise
ratio:
Dalby
NR
in;
66dB
(above
5kHz)
1-doub!
gap
ferrite
head
for
erasure
Dolby
NR
out;
56
dB
Dimentions:
36.3cm(W)
X
10.6
cm(H)
X
28.0
cm(D)
(signal
level
max.
recording
level)
Weight:
5.0kg
(without
batteries)
Fast forward and
rewind time: Approx. 130 seconds with C-60 cassette tape
Specifications are subject to chang without notice.
gees 7 Matsushita Electric Trading Co., Ltd.
Technics
P.O.
Box
288,
Central
Osaka
Japan

Technics RS-646DS-D Specifications

General

Track System	4-track, 2-channel stereo
Heads	1 x record/playback, 1 x erase
Motor	DC servo motor
Tape Type	CrO2
Input	0.25mV (mic)
Power Supply	220V

Summary

Specifications

Location of Controls and Components

Disassembly Instructions

Measurement & Adjustment

Test Instruments

Details required test instruments and their specifications for performing measurements.

Measurement Conditions

Specifies environmental and operational conditions for accurate measurements.

Test Tape

Lists the types of test tapes required and their specific uses for calibration.

Key Measurement & Adjustment Methods

Covers critical procedures like head azimuth, tape speed, frequency response, and bias current adjustments.

Adjustment Parts Location

Electrical Parts Location

Schematic Diagram

Circuit Board Diagram

Diagram showing the circuit board layout and component placement.

Wiring Connection Diagram

Exploded Views

Cabinet Parts

Replacement Parts List

Accessories

Packings