
MODEL COMMANDER DEST . CHASSIS NO.
KV-T21MN8
RM-870 Hong Kong SCC-J16G-A
KV-T21MN81
RM-870 GE SCC-J40V-A
SERVICE MANUAL
MODEL COMMANDER DEST. CHASSIS NO.
TRINITRON
®
COLOR TV
BG-1S
CHASSIS

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KV-T21MN8/T21MN81
RM-870
SPECIFICATIONS
Note
Power requirements 110-240 V AC, 50/60 Hz
Power consumption (W) Indicated on the rear of the TV
Television system B/G, I, D/K, M
Color system PAL, PAL 60, SECAM, NTSC4.43, NTSC3.58
Stereo system Nicam Stereo B/G, I; A2 Stereo (German) B/G
Teletext language English, German, Swedish, Italian, French, Spanish KV-T21MN81 only
Channel coverage
B/G VHF: E2 to E12 / UHF: E21 to E69 / CATV: S01 to S03, S1 to S41
I UHF: B21 to B68 / CATV: S01 to S03, S1 to S41
D/K VHF: C1 to C12, R1 to R12 / UHF: C13 to C57, R21 to R60 /
CATV: S01 to S03, S1 to S41, Z1 to Z39
M VHF: A2 to A13 / UHF: A14 to A79 /
CATV: A-8 to A-2, A to W+ 4, W+ 6 to W+ 84
Audio output (speaker) 3W × 2
Inputs Antenna: 75 ohms
VIDEO IN jacks: phono jacks
Video: 1 Vp-p, 75 ohms
Audio: 500 mVrms, high impedance
Outputs Headphone jack: minijack
MONITOR OUT jacks: phono jacks
Video: 1 Vp-p, 75 ohms
Audio: 500 mVrms
Picture tube 21 in.
Tube size (cm) 54 Measured diagonally
Screen size (cm) 51 Measured diagonally
Dimensions (w/h/d, mm) 527 × 464 × 471
Mass (kg) 22
Design and specifications are subject to change without notice.
CAUTION
SHORT CIRCUIT THE ANODE OF THE PICTURE TUBE AND
THE ANODE CAP T O THE METAL CHASSIS, CRT SHIELD, OR
CARBON PAINTED ON THE CRT, AFTER REMOVING THE
ANODE.
SAFETY-RELATED COMPONENT WARNING!!
COMPONENTS IDENTIFIED BY SHADING AND MARK ! ON
THE SCHEMATIC DIAGRAMS, EXPLODED VIEWS AND IN THE
PARTS LIST ARE CRITICAL T O SAFE OPERATION. REPLACE
THESE COMPONENTS WITH SONY PARTS WHOSE PART
NUMBERS APPEAR AS SHOWN IN THIS MANUAL OR IN
SUPPLEMENTS PUBLISHED BY SONY.

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KV-T21MN8/T21MN81
RM-870
TABLE OF CONTENTS
1. GENERAL.................................................................... 4
2. DISASSEMBLY
2-1. Rear Cover Removal ........................................... 10
2-2. A Board Removal ................................................ 10
2-3. F1 Board Removal ............................................... 10
2-4. Service Position ................................................... 10
2-5. Replacement of Parts ........................................... 11
2-6. Demagnetization Coil Removal .......................... 11
2-7. Picture Tube Removal ......................................... 12
3. SET-UP ADJUSTMENTS
3-1. Beam Landing ...................................................... 13
3-2. Convergence ........................................................ 14
3-3. Focus Adjustment ................................................ 16
3-4. G2 (Screen) and White Balance Adjustments..... 16
4. SELF DIAGNOSIS FUNCTION............................. 17
5. CIRCUIT ADJUSTMENTS
5-1. Adjustments with Commander ............................ 18
5-2. Adjustment Method ............................................. 19
5-3. A Board Adjustment after IC003 (Memory)
Replacement......................................................... 23
5-4. Picture Distortion Adjustment............................. 23
6. DIAGRAMS
6-1. Block Diagram ...................................................... 25
6-2. Circuit Boards Location ....................................... 29
6-3. Schematic Diagrams and Printed Wiring Boards. 29
(1) Schematic Diagram of A Board............................ 33
(2) Schematic Diagrams of A3, F1 and V1 Boards ... 37
(3) Schematic Diagrams of C and VM Boards .......... 44
6-4. Semiconductors..................................................... 49
7. EXPLODED VIEW
7-1. Chassis .................................................................. 51
8. ELECTRICAL PARTS LIST.................................... 53
Section Title Page Section Title Page

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KV-T21MN8/T21MN81
RM-870
SECTION 1
GENERAL
The operating instructions mentioned here are partial abstracts from the
Operating Instructions Manual. The page numbers of the Operating
Instruction Manual remain as in this manual.
B/G
I D/K M
TV SYSTEM
AUTO PROGR
TV SYSTEM
AUTO PROGR

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KV-T21MN8/T21MN81
RM-870
Getting Started
4
-EN
Connections
Connecting a VHF antenna or a combination VHF/UHF antenna
— 75-ohm coaxial cable (round)
Attach an optional IEC antenna connector to the 75-ohm coaxial cable.
Plug the connector into the
(antenna) socket at the rear of the TV.
Rear of TV
or
On a wall
Rear of TV
Getting Started
to video
and audio
outputs
to antenna
output
VCR
VIDEO IN
: Signal flow
Connecting optional equipment
You can connect optional audio/video equipment to your TV such as a VCR, multi disc player, camcorder, video
game or stereo system.
Connecting video equipment using video input jacks
Rear of TV
VIDEO
IN
MONITOR
OUT
VIDEO
L
(
MONO
)
AUDIO
R
to antenna socket
When connecting a monaural VCR
Connect the yellow plug to VIDEO and the black
plug to AUDIO-L (MONO).
Getting Started
5
-EN
Front of TV
Connecting audio/video equipment using MONITOR OUT jacks
to antenna
socket
Rear of TV
to antenna
output
to video
and audio
inputs
: Signal flow
or
VCR
Audio system
When using the video input jacks
Do not connect video equipment to the video input jacks at the
front and the rear of your TV simultaneously; otherwise the
picture will not be displayed properly on the screen.
VIDEO
IN
MONITOR
OUT
VIDEO
L
(
MONO
)
AUDIO
R
VIDEO
L
(
MONO
)
VIDEO INPUT
AUDIO
R
MONITOR OUT
EN
When recording through the MONITOR OUT jacks
If you change the channel or video input while recording with a
VCR, the channel or video input you are recording also will be
changed.
: Signal
flow
Camcorder
to video and
audio outputs

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KV-T21MN8/T21MN81
RM-870
7
-EN
Operations
Watching the TV
Switching off the TV
To switch off the TV temporarily, press POWER on the
remote commander.
To switch off the TV completely, press POWER on the
TV.
If the power on the TV is turned off in standby mode,
the STANDBY indicator may remain alight for a while.
Watching the video input
Press VIDEO/HOLD.
1
Press POWER to turn the TV on.
To scan through channels
Press PROGR +/– until the channel you want
appears.
3
Press VOL +/– to adjust the volume.
When the TV is in standby mode after pressing
POWER, press POWER on the remote commander.
2
Select the TV channel you want to watch.
To select a channel directly
Press a number button.
To select a two-digit channel, press “-/--” before
the number buttons.
For example: to select channel 25, press “-/- -,” and
then “2” and “5.”
To watch TV, press TV.
Muting the sound
Press MUTING.
MANUAL PROGR
COLOR SYSTEM
SELECT
TV SYSTEM
AUTO PROGR
POWER
Presetting channels
Presetting channels automatically
You can preset up to 80 TV channels in numerical
sequence from program position 1.
Front of TV
1
Press POWER.
When the TV is in standby mode after pressing
POWER, press POWER on the remote commander.
2
Press TV SYSTEM until your local TV system
appears.
3
Press AUTO PROGR.
To start presetting channels automatically
from the specified program position
1 Press MANUAL PROGR.
2 Press TV SYSTEM to select your local TV system.
3 Press PROGR +/– to select the program position.
4 Press AUTO PROGR.
Presetting channels manually
To change the channel for a particular program
position or to receive a channel with a weak signal,
preset the channel manually.
1
Press MANUAL PROGR.
2
Press PROGR +/– until the required program
position appears on the screen.
3
Press TV SYSTEM until your local TV system
appears.
4
Press VOLUME +/– on the TV until the
required channel picture appears on the
screen.
5
Press MANUAL PROGR.
If the TV system is not properly selected
The color of the picture may be poor and/or the sound
may be noisy. In this case, select the appropriate TV
system.
1 Press PROGR +/– to select the program position.
2 Press TV SYSTEM until the picture and sound
become normal.
Notes
• If you do not know your local TV system, consult your nearest
authorized service center or dealer.
• The setting of the TV SYSTEM is memorized for each program
position.
Disabling program positions
By disabling unused or unwanted program positions,
you can skip those positions when you press PROGR
+/–.
1
Press PROGR +/– until the unused or
unwanted program position appears on the
screen.
2
Press MANUAL PROGR.
3
Press PIC MODE on the remote commander.
4
Press MANUAL PROGR.
To cancel the skip setting
Preset the channel manually or automatically again.
1
32

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KV-T21MN8/T21MN81
RM-870
Operations
8
-EN
turns into standby mode will appear when the TV is turned on
using the Wake Up Timer.
• If no buttons or controls are pressed for more than two hours
after the TV is turned on using the Wake Up Timer, the TV
automatically turns into standby mode. When you want to
continue watching the TV, press any button or control on the
TV or remote commander.
Setting the Sleep Timer
You can set the TV to turn off automatically after the
period of time you want.
Press SLEEP.
To cancel the Sleep Timer, press SLEEP repeatedly
until “SLEEP TIMER: OFF” appears, or turn the TV off.
Changing the on-screen display
language
If you prefer Chinese to English, you can change the
on-screen display language. You can use buttons on the
remote commander or the TV.
1
Press SELECT until the screen appears as
follow:
2
Press + or – to select “⁄⁄⁄ ”.
Note
• You can also use VOLUME +/– on the TV to select the on-
screen display language.
Displaying on-screen information
Press DISPLAY/REVEAL.
The program position, local system, and TV settings are
displayed on the screen.
Setting the Wake Up Timer
You can set the TV to turn on automatically after the
period of time you want.
1
Press WAKE UP/INDEX repeatedly to set the
timer.
The on-screen display appears and the WAKE UP/
STEREO indicator lights up.
2
If you want a particular TV program or
video input to be displayed using the Wake
Up Timer, select the TV program or video
mode.
3
Press POWER on the remote commander or
set the Sleep Timer to turn off the TV in
standby mode.
To cancel the Wake Up Timer, press WAKE UP/
INDEX repeatedly until “WAKE UP TIMER: OFF”
appears, or turn off the main power of the TV.
Notes
• The Wake Up Timer starts immediately after the on-screen
display disappears.
• The last TV program position or video mode just before the TV
WAKE UP TIMER:10M
WAKE UP TIMER:OFF
WAKE UP TIMER:12H00M
After 12
hours
No wake up timer
After 60 minutes
After 90 minutes
No sleep timer
After 30 minutes
SLEEP TIMER:30M
SLEEP TIMER:60M
SLEEP TIMER:OFF
SLEEP TIMER:90M
LANGUAGE / : ENGLISH
SELECT
LANGUAGE / »y¤¥¡GENGLISH
»y¤¥ / LANGUAGE: ⁄⁄⁄
After 10 minutes
9
-EN
Operations
Adjusting the picture
and sound
Selecting the picture mode
Press PIC MODE until the mode you want
appears.
Each time you press PIC MODE, the screen changes as
follows:
Note
• If you change the picture mode after the following
adjustments, the adjustment changes in accordance with the
picture mode.
Adjusting the picture and sound
settings
1
Press SELECT until the item you want to
adjust appears.
+ or –
SELECT
PIC MODE
Each time you press SELECT, the screen changes as
follows:
2
Press + or – to adjust the item.
3
To adjust other items, repeat steps 1 and 2.
Note
• You can also use VOLUME +/– on the TV to adjust the picture
and sound settings.
If the color of the picture is abnormal
When receiving programs through the
terminal:
Press TV SYSTEM or COLOR SYSTEM or adjust the
color setting until the color becomes normal.
Note
• Normally set COLOR SYSTEM to AUTO.
If the sound is distorted or noisy
When receiving programs through the
terminal:
Press TV SYSTEM until the sound becomes clear.
Front of TV
Soft picture
(good for
video games)
PICTURE
COLOR
BRIGHT
HUE
SHARPNESS
BASS
BALANCE
TREBLE
SURROUND
TILT CORRECTION
(Operative for
NTSC signal only)
MANUAL PROGR
COLOR SYSTEM
SELECT
TV SYSTEM
AUTO PROGR

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KV-T21MN8/T21MN81
RM-870
11
-EN
Operations
Viewing Teletext
11
-EN
p KV-T21MN81 only
Displaying Teletext
1
Select a TV channel which carries the Teletext
broadcast you want to watch.
2 Press TEXT to display the Teletext.
A Teletext page is displayed (normally the index
page). If there is no Teletext broadcast, 100 is
displayed at the top left corner of the screen.
To cancel the Teletext display, press TV.
Superimposing a Teletext page on the TV
picture
Press TEXT.
Each time you press TEXT, the screen changes as
follows:
z Teletext z Teletext and TV z TV
Checking the contents of a Teletext service
(INDEX)
Press WAKE UP/INDEX to display an overview of the
Teletext contents and page numbers.
DISPLAY/REVEAL
TEXT
TEXT CLR
WAKE UP/INDEX
VIDEO/HOLD
TV
Number
FASTEXT
Using FASTEXT
This feature allows you to quickly access a Teletext
page that uses FASTEXT. When a FASTEXT page is
broadcasted, a color-coded menu appears at the bottom
of the screen. The colors of the menu correspond to the
RED, GREEN, YELLOW, and CYAN buttons on the
remote commander.
Press the color button which corresponds to the colorcoded menu.
The page is displayed after a few seconds.
Selecting a Teletext page
To input the three-digit page number of the Teletext
page, press the number buttons.
If you make a mistake, key in the correct page number
again.
To access the next or previous page, press PROGR +/–.
Holding a Teletext page (subpage)
Press VIDEO/HOLD.
The HOLD symbol “˝ ” is displayed at the top left
corner of the screen.
To resume normal Teletext operation, press VIDEO/
HOLD again or TEXT.
Revealing concealed information
Press DISPLAY/REVEAL.
To conceal the information, press DISPLAY/REVEAL
again.
Enlarging the Teletext display
Press A/B/ENLARGE.
Each time you press A/B/ENLARGE, the Teletext
display changes as follows:
zz z Normal size
Waiting for a Teletext page while watching a
TV program (TEXT CLEAR)
1 Key in the page number of the Teletext that you
want to refer, then press TEXT CLR.
2 When the page number is displayed on the screen,
press TEXT to switch the Teletext on.
Enlarge
lower half
Enlarge
upper half
PROGR +/–
A/B/ENLARGE
Operations
10
-EN
Selecting a stereo or
bilingual program
Press A/B/ENLARGE repeatedly until you
receive the sound you want.
The on-screen display changes corresponding to the
selected sound and the WAKE UP/STEREO indicator
also lights up.
When receiving a NICAM program
Broadcasting
NICAM stereo
NICAM bilingual
NICAM monaural
When receiving a A2 (German) program
Broadcasting
A2 (German)
stereo
A2 (German)
bilingual
Receiving area for NICAM and A2 (German)
programs
System
NICAM
A2 (German)
Notes
• If the signal is very weak, the sound becomes monaural
automatically.
• If the stereo sound is noisy, select “regular sound.” The sound
becomes monaural, however, the noise will be reduced.
Receiving area
Hong Kong, Singapore, New Zealand,
etc.
Australia, Malaysia, Thailand, etc.
On-screen display
(Selected sound)
On-screen display
(Selected sound)
NICAM
z MONO
(Regular sound)
NICAM
z MONO
(Regular
sound)
NICAM
z MAIN
(Main sound)
NICAM
z SUB
(Sub sound)
NICAM
z MAIN
(Main sound)
NICAM
z MONO
(Regular sound)
STEREO
z MAIN
(Main sound)
STEREO
z SUB
(Sub sound)
STEREO
(Stereo sound)

– 9 –
KV-T21MN8/T21MN81
RM-870
12
-EN
Additional Information
Troubleshooting
Good picture
Noisy sound
/Check the TV SYSTEM setting.
No picture
No sound
/Press POWER.
/Check the antenna connection.
/Check the VCR connections.
/Check the power cord connection.
/Check the standby mode.
Good picture
No sound
/Press VOLUME +.
/Press MUTING.
/Press A/B/ENLARGE.
No color
/Adjust the COLOR level in the on-screen
display.
/Check the COLOR SYSTEM setting.
TV cabinet creaks
/Even if the picture or the sound is normal,
changes in the room temperature
sometimes make the TV cabinet expand or
contract, making a noise. This does not
indicate a malfunction.
WARNING
Do not install the appliance in a confined space, such as
a bookcase or built-in cabinet.
Additional Information
If you have any problems, read this manual again and
check the countermeasure for each of the symptoms
listed below.
If the problem persists, contact your nearest authorized
service center or dealer.
Snowy picture
Noisy sound
/Check the antenna.
/Check the antenna connection on the TV
and on the wall.
/Check the TV SYSTEM setting.
Dotted lines or stripes
/This may be caused by local interference
(e.g. cars, neon signs, hair dryers, etc.).
Adjust the antenna for minimum
interference.
Double images or “ghosts”
/This may be caused by reflections from
nearby mountains or buildings. A highly
directional antenna may improve the
picture.
Notes
• When you switch on the TV, you may hear the “boon” sound
that is caused by the demagnetization of the TV. This does not
indicate a malfunction.
• The picture color may become abnormal if you change the
direction of your TV. To obtain the normal picture color, press
POWER on the TV to switch off the TV for five minutes and
then switch it on again.
• Design and specifications are subject to change without notice.

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KV-T21MN8/T21MN81
RM-870
2-1. REAR COVER REMOVAL 2-3. F1 BOARD REMOVAL
(EXCEPT FOR KV-T21MN81)
SECTION 2
DISASSEMBLY
2-2. A BOARD REMOVAL
2-4. SERVICE POSITION
2
Two screws
(BVTP 4×16)
3
One screw
(BVTP 3×16)
1
Two screws
(BVTP 4×16)

– 11 –
KV-T21MN8/T21MN81
RM-870
2-5. REPLACEMENT OF PARTS
For replacement of the Multi Button, Power Button and Light Guide, cut the welded portions
from them, exchange with the new parts, and fix them with screws (+BVTP) respectively.
2-5-1. REPLACEMENT OF MULTI BUTTON
2-5-2. REPLACEMENT OF POWER BUTTON AND LIGHT GUIDE
2-6. DEMAGNETIZATION COIL REMOVAL
Cut
Light guide
Power button
1
Demagnetization coil
2
Tension spring
Picture tube

– 12 –
KV-T21MN8/T21MN81
RM-870
2-7. PICTURE TUBE REMOVAL
2 Using a thumb press down then pull up the rubber cap firmly in the direction
indicated by the arrow b.
3 When one side of the rubber cap is separated from the anode button, the
anode-cap can be removed by turning up the rubber cap and pulling it up in the
direction of the arrow c.
• HOW TO HANDLE AN ANODE-CAP
1 Do not damage the surface of anode-caps with sharp shaped objects.
2 Do not press the rubber too hard so as not to damage the inside of anode-caps.
A metal fitting called the shatter-hook terminal is built into the rubber.
3 Do not turn the foot of rubber over too hard.
The shatter-hook terminal will stick out or damage the rubber.
•REMOVAL OF ANODE-CAP
NOTE : After removing the anode, short circuit the anode of the picture tube and the
anode cap to the metal chassis, CRT shield or carbon paint on the CRT.
•REMOVING PROCEDURES
1 Turn up one side of the rubber cap in the direction indicated by the arrow a.
2 A board
5 Deflection yoke
Cushion
6 Four screws
(Tapping screws)
1 Anode cap
4 C board
3 F1 board
7 VM board