Variable Resistors - Technics RS-D225W Service Manual

Dolby nr-equipped double cassette deck
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Notes:
°
Part numbers are indicated on most mechanical parts.
Please use this part number for parts order.
Important safety notice:
Components
identified
by /\ mark
have
special
characteristics important for safety.
When replacing any of these components, use only
manufacturer's specified parts.
@ SCHEMATIC DIAGRAM
AN7014K
MN6634
TRANSISTORS
Q13, 14, 21~24,
301, 302, 811
Q15~18, 806
Q31
UN4213
2S8B621A—R
2SB10300
Q303 [EK, XL]
Q303 [other]
2SD592ANC—Q
Q304, 601, 807,
808
Q401~404
28C3311—Q
2SB621A—R
28014230
UN4113
UN4114
UN4116
2SK381D
D5, 6, 8, 9, 13, 609,
1SS254
819~822
D7, 10, 301,302,
MA165
MA4160M
1SR35200
MA4062—M
LN463YCPPU
LN&63RCPP
LN846RP
LN346GP
LN446YP
SLQX303—1K
QLQX2722D
SLO9C19—K
QLM9Z10K
VARIABLE RESISTORS
EVND4AA00B24
EWAPB1X05A54
EVND4AA00B14
EVND4AA00B15
EVND1AA00B14
Ic
Transistor
Transistor
Transistor
Transistor
Transistor
Transistor
Transistor
Transistor
Transistor
Transistor
Transistor
Transistor
Transistor
Transistor
Transistor
Choke
Choke
Bias OSC
MPX Coil
Tape 1/Tape 2
P.B. Gain Adj.
Input Volume
Overall Gain
Adj.
Bias Current
Adj.
Tape Speed Adj.
COMBINATION PART
7801
EXBF7E562J
5.6KQx6
SWITCHES
S1, 801, 802
SSH3702
$601
A. SSH1069
$901~906
SSP83
$907~909
LSA—1150AU
NR Editing
Switch
Power Switch
' Leaf Switch
Leaf Switch
Notes:
esi
: Dolby NR switch in "out" position.
e $601
: Power switch in "off" position.
¢ $801
: Editing switch in "off" position.
¢ $802
: Editing tape speed select switch in '"'Normal" position.
e $901
: Tape (2) play switch in "off'' position.
e¢ $902
: Tape @ play switch in "off" position.
¢ $903
: Tape [2] motor switch in "off" position.
¢ $904
: Tape ) motor switch in "off" position.
¢ $905
: Tape 2) rec switch in "off" position.
¢ $906
: Tape () FF/REW switch in "off" position.
¢ $907
: Tape [2] Normal switch in "off" position.
¢ $908
: Tape [2] CrO2 switch in "off" position.
¢ $909
: Tape 1 70uS switch in "off" position.
© Resistance are in ohms (Q), 1/4 watt unless specified otherwise.
1K=1,000(Q), 1M=1,000k(Q)
© Capacity are in micro-farads (uF) unless specified otherwise.
¢ All voltage values shown in circuitry are under no signal condition and
Tape 2) playback mode with volume control at minimum position
otherwise specified.
Voltage values at record mode.
..Voltage values at CrO, tape mode.
.. Voltage values at Metal tape mode.
..Voltage values at Dolby NR mode.
Voltage values at editing mode.
For measurement use EVM.
e(
) indicates B (bias).
© (ssi)
indicates the flow of the playback signal.
* (C===>)) indicates the flow of the record signal.
¢ Important safety notice
Components identified by A\ mark have special characteristics impor-
tant for safety.
When replacing any of these components, use only
manufacturer's specified parts.
* Caution!
IC and LSI are sensitive to static electricity.
¢ Cover the parts boxes made of plastics with aluminum foil.
e Ground the soldering iron.
e Put a conductive mat on the work table.
e Do not touch the legs of IC or LSI with the fingers directly.
@ EQUIVALENT CIRCUIT
1C701: AN6888
Playback S/N ratio
* Test tape... QZZCFM
Overall distortion
* Test tape
%* Input level control... MAX
Greater than 45dB
Less than3.5%
Overall S/N ratio
* Test tape... QZZCRA
Greater than 43dB
(without NAB filter)
m
Ei main circuit section
IN/OUT CONNECTOR
Bias Current Adj. <4
Q5,6
C4 390P
2$D1330R
X1/X2 DRIVE
REC/PLAY AMP, MU,
1C4
MN6634
T1/T2 SELECTOR
Q13, 14
Q21~24
28C33110
TAPE SELECTOR
SD592ANC-Q)
BIAS CONTROL
Q15~18
2SA1309Q
TAPE SELECTOR
Q801
UN4113
X1/X2 CONTROL
19
V1
12
R18. +
30mH
10K
R25 33
13 2.7mH
C16
100P
Q804
Sx
UN4116
es
BIAS CONTROL
Q301, 302
2SB10300
28C3311Q
REC LED
BIAS OSC
CONTROL
Metal:(6.7)_|
-6.2 (0.2)
Metal:(6.7)
Cr02:(2.6)
\
QB3, 34
LED CIRCUIT SECTION
cee
UTING DRIVE
=
22>

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