Sony TC-KB820S User manual

MICROFILM
SERVICE MANUAL
STEREO CASSETTE DECK
AEP Model
UK Model
Australian Model
Model Name Using Similar Mechanism TC-KE400S
Tape Transport Mechanism Type TCM-190VB12CSS
SPECIFICATIONS
TC-KB820S
Dolby noise reduction and HX Pro headroom ex-
tension manufactured under license from Dolby
Laboratories Licensing Corporation. HX Pro origi-
nated by Bang & Olufsen.
“DOLBY”, the double-D symbol a, and “HX PRO”
aretrademarks ofDolbyLaboratoriesLicensingCor-
poration.
– Continued on next page –

– 2 –
Flexible Circuit Board Repairing
• Keep the temperature of the soldering iron around 270 ˚C dur-
ing repairing.
• Do not touch the soldering iron on the same conductor of the
circuit board (within 3 times).
• Be careful not to apply force on the conductor when soldering
or unsoldering.
Notes on chip component replacement
• Never reuse a disconnected chip component.
• Notice that the minus side of a tantalum capacitor may be dam-
aged by heat.
SAFETY-RELATED COMPONENT WARNING!!
COMPONENTS IDENTIFIED BY MARK !OR DOTTED
LINE WITH MARK !ON THE SCHEMATIC DIAGRAMS
AND IN THE PARTS LIST ARE CRITICAL TO SAFE
OPERATION. REPLACE THESE COMPONENTS WITH
SONY PARTS WHOSE PART NUMBERS APPEAR AS
SHOWN IN THIS MANUAL OR IN SUPPLEMENTS PUB-
LISHED BY SONY.
MODEL IDENTIFICATION
– BACK PANEL –
3-020-983-
AEP Model : 0
π
UK Model : 1 π
Australian Model : 2 π

– 3 –
TABLE OF CONTENTS
1. GENERAL ................................................................... 4
2. DISASSEMBLY ......................................................... 5
3. MECHANICAL ADJUSTMENTS....................... 9
4. ELECTRICAL ADJUSTMENTS......................... 10
5. DIAGRAMS
5-1. Note for Printed Wiring Boards and
Schematic Diagrams ....................................................... 14
5-2. Printed Wiring Boards – MD Section –......................... 15
5-3. Schematic Diagram – MD Section – .............................. 17
5-4. Printed Wiring Board – MAIN Section – ...................... 19
5-5. Schematic Diagram – MAIN Section – (1/3)................. 21
5-6. Schematic Diagram – MAIN Section – (2/3)................. 23
5-7. Schematic Diagram – MAIN Section – (3/3)................. 25
5-8. Printed Wiring Board – DOLBY-S Section –................ 29
5-9. Schematic Diagram – DOLBY-S Section – .................. 29
5-10. Printed Wiring Boards – PANEL Section – .................. 31
5-11. Schematic Diagram – PANEL Section – ........................ 33
5-12. IC Pin Function Description ........................................... 35
6. EXPLODED VIEWS................................................ 37
7. ELECTRICAL PARTS LIST ............................... 42

– 4 –
SECTION 1
GENERAL
LOCATION OF CONTROLS
1I/O (Power) button
2Remote control sensor
3PHONES jack
4Display panel
5Tape operation buttons
AMS* 0button
·button
AMS* )button
pbutton
PPAUSE button
RREC MUTING button
rREC button
6Tape counter
7Counter buttons
RESET button
MEMORY button
8Cassette holder
9§EJECT button
!º AUTO CAL button
!¡ DOLBY NR switch
!™ BALANCE control
!£ REC LEVEL control
* AMS is an abbreviation for Automatic Music Sensor.

– 5 –
FRONT PANEL SECTION
MD ASS’Y SECTION
Note: Follow the disassembly procedure in the numerical order given.
SECTION 2
DISASSEMBLY
CASE
Unscrew the four case attachment seven tapping screws
and remove the case.
1 flat cable
(CN801)
3 screw
(BVTP3
× 8)
5 four screws
(BVTP3
× 8)
7 two connectors
(CNP31, 33)
5 screw
(BVTP3
× 8)
6 claw
6 claw
1 flat cabl
e
(CN504)
4 two earth
lugs
2 connector
(CN704)
1 flat cable
(CN81)
2 connector
(CN506)
8 front panel section
4 two screws
(BVTT2.6
× 8)
6 Remove the MD ass’y section
to direction of arrow
A .
5 two screws
(BVTP2.6
× 8)
2 two claws
1 push the eject
button.
2 two claws
3 cassette lid
ass’y
A

– 6 –
MAIN BOARD
CASSETTE HOLDER (R) ASS’Y
4 two screws
(BVTP3
× 8)
2 screw
(BV/ring)
5 MAIN board
1 connector
(CN701)
4 screw
(BV/ring)
3 bracket (TR)
2 boss
3 shaft
1 torsion spring
4 cassette holder (R)
ass’y

– 7 –
FITTING BASE BLOCK
HEAD
2 two screws
(PTPWH2
× 23)
2 screw
(PTPWH2
× 23)
Note: When installing, pull
the FR belt and put
around the claws as
shown below.
1 connector
(CNP32)
3 fitting base block
Note: When installing, pull the capstan belt
and put around the claws as shown below.
2 screw
(B2
× 10)
1 connecto
r
(CNP32)
4 azimuth screw
5 record/playback head
6 compression spring
3 erase head

– 8 –
MOTOR
5 two screws
(B2.6
× 3)
7 two screws
(P2.6
× 2.8)
2 flexible board
(CNP72)
1 connector
(CNP71)
3 claw
3 claw
3 two
claws
6 capstan motor
!º ground plate
4 audio
boar
d
8 reel motor
9 FR belt

– 9 –
SECTION 3
MECHANICAL ADJUSTMENTS
PRECAUTION
1. Clean the following parts with a denatured alcohol-moistened
swab:
record/playback/erase head pinch roller
rubber belts capstan
idler
2. Demagnetize the record/playback head with a head demagne-
tizer.
(Head demagnetizer do not approach for the erase head.)
3. Do not use a magnetized screwdriver for the adjustment.
4. After the adjustments, apply suitable locking compound to the
parts adjusted.
5. The adjustments should be performed with the rated power
supply voltage unless otherwise noted.
•Torque Measurement
Mode Torque Meter Meter Reading
Forward CQ-102C 30 to 60 g•cm
(0.42 to 0.83 oz•inch)
Forward
back CQ-102C 2 to 7 g•cm
tension (0.03 to 0.09 oz•inch)
FF/REW CQ-201B 70 to 110 g•cm
(0.98 to 1.52 oz•inch)

– 10 –
SECTION 4
ELECTRICAL ADJUSTMENTS
Note: The adjustment should be performed in the order given in the ser-
vice manual.As a rule, adjustments about playback should be per-
formed before those about recording.
The adjustments should be performed before for both L-CH and R-
CH.
• Switches and controls should be set as follows unless otherwise
specified.
DOLBY NR, MPX FILTER switch: OFF
• Standard Record:
Deliver the standard input signal level to the input jack and set
the REC LEVEL control to obtain the standard output signal
level.
– Record Mode –
0 dB = 0.775 V
Standard Input Level
input terminal LINE IN
source impedance 10 kΩ
input signal level 0.5 V (–3.8 dB)
Standard Output Level
output terminal LINE OUT
load impedance 47 kΩ
output signal level 0.5 V (–3.8 dB)
TestTape
Type Signal Used for
P-4-A100 10 kHz, –10 dB Azimuth Adjustment
P-4-L300 315 Hz, 0 dB Playback Level Adjustment
WS-48B 3 kHz, 0 dB Tape Speed Adjustment
Test Mode
1. Insert a short-circuit plug into TP801 (2P) and turn ON the
power switch. (Earth pin &ª of IC801 and turn ON the power
switch.)
At first, all the fluorescent tubes light up, then the system re-
turns to normal display. (However, “00 00” is not displayed on
the counter.)
2. To release the test mode, remove the short plug and turn off
the power switch.
3. Remove the short plug after completion of adjustment.
+
–
set
47 k
Ω
LINE OUT
LINE IN
600
Ω
10 k Ω
attenuator
AF OSC level meter
Record/Playback Head Azimuth Adjustment
Procedure:
1. Mode : FWD playback
2. Turn the adjustment screw for the maximum output levels. If
these levels do not match, turn the adjustment screw until both
of output levels match together within 1 dB.
3. Phase Check
Mode : playback
4. After the adjustment, lock the screw with locking compound.
Adjustment Location: Record/Playback head
+
–
set
47 k
Ω
LINE OUT
level mete
r
Test tape
P-4-A100
(10 kHz, –10 dB)
Screw
position
L-CH
peak
within
1dB
output
level
L-CH peak R-CH peak
within
1dB
angl
e
R-CH
peak
+
–
VH
+
–
Screen pattern
Good Wrong
in phase 45
° 90 ° 135 ° 180 °
LINE OUT
set
R-CH
L-CH 47 k
Ω
47 k Ω
oscilloscope
test tape
P-4-A100
(10 kHz, –10 dB)
Adjustment screw

– 11 –
Tape Speed Adjustment
Procedure:
Mode: playback
1. Set to FWD playback mode.
2. Adjust RV71 so that the frequency counter reading becomes
3,000 ± 90 Hz.
3. If, the frequency counter reading does not become 3,000 ±
90Hz.
Turn RV72 and back to 1st. step again.
Note: Turn RV72 to clockwise – Tape speed becomes fast.
Turn RV72 to counter clockwise – Tape speed becomes slow.
4. Frequency difference between the beginning and the end of
the tape should be within 1%.
Adjustment Location: AUDIO board (See page 12.)
Sample value of Wow and Flutter: 0.3% or less W.RMS (JIS)
(WS-48B)
Playback Level Adjustment
Procedure:
Mode: playback
Adjust RV11 (L-CH) and RV21 (R-CH) so that the reading on
level meter meets the adjustment limits below.
Adjustment Limits:
LINE OUT level: –7.7±0.5 dB (0.301 to 0.338 V)
Level difference between channels: within 0.5 dB
Check that the LINE OUT level does not change even if Playback
and Stop operation is repeated several times.
Adjustment Location: AUDIO board (See page 12.)
+
–
set
LINE OUT
frequency counte
r
test tape
WS-48B
(3 kHz, 0 dB) 47 k
Ω
+
–
set
LINE OUT
47 k
Ω
test tape
P-4-L300
(315 Hz, 0 dB) level mete
r
Bias Consumption Current Adjustment
Procedure:
1. Set RV81 (L-CH) and RV91 (R-CH) to mechanical center and
turn the set recording mode.
2. Connect digital voltmeter as shown by the following table.
3. Adjust the following transformers for the minimum readings
on the digital voltmeter.
Measurement Point Adjustment Part Value
L-CH 1and 2, TP321 T81 minimum
R-CH 3and 2, TP321 T91
Adjustment Location:AUDIO board (See page 12.)
Record Bias Adjustment
Setting:
REC LEVEL control: Standard Record (See page 10.)
Procedure:
1. Mode: record
2. Mode: playback
3. Adjust RV81(L-CH) and RV91 (R-CH) so that 10 kHz play-
back output is 0±0.5 dB relative to the 315 Hz output.
Adjustment Location:AUDIO board (See page 12.)
–
+
set
LINE IN
(no signal)
B+ (+7.5 V)
TP81
321
R-CH
L-CH
digital voltmete
r
CS-413 blank tape
set
AF OSC
Attenuator
LINE IN
315 Hz
10 kHz 50 mV (–23.8 dB)
600
Ω
10 k Ω
CS-123
blank tape
+
–
set
LINE OUT
47 k
Ω
recorded
portion level mete
r

– 12 –
Record Level Adjustment
Setting:
REC LEVEL control: Standard Record (See page 10.)
Procedure:
1. Mode: record
2. Mode: playback
3. Adjust RV111 (L-CH) and RV211 (R-CH) so that the reading
on level meter meets the adjustment limits below.
Adjustment Limits: –3.8 ± 0.5 dB (0.47 to 0.53 V)
Adjustment Location: MAIN board
[AUDIO BOARD] –SIDE A –
set
AF OSC
Attenuator
600
Ω
10 k Ω
CS-123
blank tape
LINE IN
315 Hz, 0.5 V (–3.8 dB)
+
–
set
LINE OUT
47 k
Ω
recorded
portion level mete
r
Adjustment Location:
[MAIN BOARD] –COMPONENT SIDE –
DOLBY-S
BOARD
RV211 RV111
J501
CN831 CN833
TP801
RV72
RV71
RV21
RV11
T81
T91
RV81
IC31
TP81
RV91

– 13 – – 14 –
SECTION 5
DIAGRAMS
•Circuit Boards Location
TRANSFORMER board
AC POWER
SW board
HP board
PANEL board
LEAF SW board
REC VOL board
DOLBY-S board
s
MAIN board
AUDIO board
5-1. NOTE FOR PRINTED WIRING BOARDS AND SCHEMATIC DIAGRAMS
(In addition to this, the necessary note is each block.)
Note on Schematic Diagram:
• All capacitors are in µF unless otherwise noted. pF: µµF
50 WV or less are not indicated except for electrolytics
and tantalums.
• All resistors are in Ωand 1/4W or less unless otherwise
specified.
•¢: internal component.
•2: nonflammable resistor.
•C: panel designation.
•U: B+ Line.
•V: B– Line.
• Voltages and waveforms are dc with respect to ground
under no-signal conditions.
no mark : PB
( ) : REC
∗: Impossible to measure
• Voltagesare takenwith aVOM (Inputimpedance 10MΩ).
Voltage variations may be noted due to normal produc-
tion tolerances.
• Waveforms are taken with a oscilloscope.
Voltage variations may be noted due to normal produc-
tion tolerances.
• Circled numbers refer to waveforms.
• Signal path.
E: PB
a: REC
Note: The components identified by mark !or dotted line
with mark !are critical for safety.
Replace only with part number specified.
Note on PrintedWiring Boards:
•X: parts extracted from the component side.
•Y: parts extracted from the conductor side.
•r:Through hole.
•b: Pattern from the side which enables seeing.
(The other layers' patterns are not indicated.)
Caution:
Pattern face side: Partsonthepatternfaceside seenfrom
(Side B) the pattern face are indicated.
Parts face side: Parts on the parts face side seen from
(Side A) theparts face are indicated.
• Indication of transistor.
B
These are omitted.
CE
Q
B
These are omitted.
CE
Q

– 15 – – 16 –
TC-KB820S
5-2. PRINTED WIRING BOARDS – MD Section – • See page 13 for Circuit Boards Location.
• Semiconductor
Location
Ref. No. Location
D31 C-1
IC31 C-2
IC81 B-3
•IC81 G-4
Q51 B-2
Q52 B-2
Q53 B-2
Q71 C-4
(Note) •:LEAF SW BOARD
(Page 20) (Page 19)
(Page 19)

TC-KB820S
– 18 –– 17 –
5-3. SCHEMATIC DIAGRAM – MD Section – • See page 27 for Waveforms.
(Page 21)
(Page 21)
(Page 23)

– 19 – – 20 –
TC-KB820S
5-4. PRINTED WIRING BOARD – MAIN Section – • See page 13 for Circuit Boards Location.
• Semiconductor
Location
Ref. No. Location
D131 C-5
D132 C-5
D231 C-5
D232 C-5
D511 B-7
D512 B-7
D513 E-7
D551 B-5
D701 G-2
D702 G-2
D703 G-2
D704 G-2
D705 F-2
D706 F-2
D707 F-2
D708 G-3
D709 G-5
D710 F-3
D711 F-4
D712 F-3
D713 E-1
D714 E-3
D715 F-4
D801 D-2
D802 D-2
IC501 C-9
IC502 F-9
IC503 D-6
IC504 C-5
IC505 D-5
IC506 A-9
IC507 C-7
IC508 B-4
IC509 C-4
IC510 B-6
IC511 F-10
IC512 D-9
IC601 A-3
IC701 G-4
IC801 B-2
IC802 D-2
Q101 A-8
Q102 B-8
Q103 E-8
Q121 F-6
Q122 D-7
Q201 A-8
Q202 B-10
Q203 E-9
Q221 F-6
Q222 D-7
Q503 E-8
Q511 B-6
Q512 B-7
Q521 F-7
Q531 B-5
Q532 B-5
Q551 A-5
Q572 F-7
Q573 C-7
Q601 B-3
Q701 G-6
Q702 G-5
Q704 G-4
Q705 F-3
Q707 F-3
Q708 F-2
Q805 D-2
(Page 32)
(Page 31) (Page 15) (Page 32) (Page 31)
(Page 29)
(Page 29)
(Page 15) (Page 15)

TC-KB820S
– 22 –– 21 –
5-5. SCHEMATIC DIAGRAM – MAIN Section – (1/3)
(Page 30)
(Page 34)
(Page 18)
(Page 18)
(Page 30)
(Page 23)
(Page 23)
The components identified by mark !or dotted
line with mark !are critical for safety.
Replaceonly withpart numberspecified.

– 23 – – 24 –
TC-KB820S
5-6. SCHEMATIC DIAGRAM – MAIN Section – (2/3) • See page 27 for Waveforms.
(Page 22)
(Page 22)
(Page 18)
(Page 25)
(Page 25)

TC-KB820S
– 26 –– 25 –
5-7. SCHEMATIC DIAGRAM – MAIN Section – (3/3) • See page 28 for IC Block Diagrams.
The components identified by mark !or dotted
line with mark !are critical for safety.
Replaceonly withpart numberspecified.
(Page 33)
(Page 33)
(Page 34)
(Page 24)
(Page 24)

– 27 – – 28 –
• Waveforms
– AUDIO BOARD –
1T51 1
2Q51 C, Q52 C
3T81 4
4T91 4
6IC81 !¡, !™
– MAIN BOARD (2/3) –
1IC801 #¡
5IC81 7, 8
118 Vp-p
9.3
µ
s
26.4 Vp-p
9.3 µ s
63.2 Vp-p
9.3 µ s
64.8 Vp-p
9.3 µ s
6.4 Vp-p
9.3
µ
s
4.3 Vp-p
6 MHz
6.2 Vp-p
9.3 µ s
• IC Block Diagrams
2
1
RECOUT
SCINL ANTSAT
MC3IN
MC4IN
HLSOUT
MCBO
VCC
IREF SCBOL
TCS2L
TCS1L
FBOL TCF1L
TCF2L
4
LFIN
3
TCL2
ZL2
59
8
7
6
TCL1
SCINH
TCS1H
ZL1
HLSMP
MCTC
10 11 12 13
VCT
14
VEE
15
24
25
2627
28
29
30 20
21
22
23 19 17
18 16
TCS2H
TCF2H
FBOH
TCF1H
ANTSAT
FLVCR SLVCR
FHVCR
LFICGLFVCR
LFDET SHVCR
SLDET SLICG
SHICGSHDET
FLDET
FHDET
FLICG
FHICG
V TO I
CONV H
V TO I
CONV H
VREF &
IREF
MC4
MC3DS
MC3DT
MC2
MC1
MC4
MC3
MC1
MC
IC1 CXA1917AM-T6 (DOLBY-S BOARD)
IC502 CXA1579P (MAIN BOARD)
2
1
MUTE
R.CAL
G.CAL
IN
I.REF
BOOST
VCC OUT
4
35
9
8
7
6
VEE
IN
10
11
12
13
GND
14
BOOST
15
16
70US
METAL
OUT
SPEED
CONTROL REC EQ AMP
REC EQ AMP
BIAS
+ –
VGS
VEE
VCC