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