SONY 27V412T Service Manual

SAFETY PRECAUTIONS

SERVICE WARNING

Only qualified service technicians who are familiar with safety checks
and guidelines should perform service work. Before replacing parts,
disconnect power source to protect electrostatically sensitive parts. Do
not attempt to modify any circuit unless so recommended by the
manufacturer. When servicing the receiver, use an isolation transformer
between the line cord and power receptacle.

SERVICING THE HIGH VOLTAGE AND CRT

Use EXTREME CAUTION when servicing the high voltage circuits. To
discharge static high voltage, connect a 10K ohms resistor in series with a
test lead between the receiver ground and CRT anode lead. DO NOT lift
the CRT by the neck. Always wear shatterproof goggles when handling
the CRT to protect eyes in case of implosion.

X-RAY RADIATION AND HIGH VOLTAGE LIMITS

Be aware of the instructions and procedures covering X-ray radiation. In
solid-state receivers and monitors, the CRT is the only potential source of
X-rays. Keep an accurate high voltage meter available at all times. Check
meter calibration periodically. Whenever servicing a receiver, check the
high voltage at various brightness levels to be sure it is regulating
properly. Keep high voltage at rated value, NO HIGHER. Excessive high
voltage may cause X-ray radiation or failure of associated components.
DO NOT depend on protection circuits to keep voltage at rated value.
When troubleshooting a receiver with excessive high voltage, avoid close
contact with the CRT. DO NOT operate the receiver longer than
necessary. To locate the cause of excessive high voltage, use a variable
AC transformer to regulate voltage. In present receivers, many electrical
and mechanical components have safety related characteristics which are
not detectable by visual inspection. Such components are identified by a
# on both the schematic and the parts list. For SAFETY, use only
equivalent replacement parts when replacing these components.

GENERAL GUIDELINES

Perform a final SAFETY CHECK before returning receiver to customer.
Check repaired area for poorly soldered connections, and check entire
circuit board for solder splashes. Check board wiring for pinched wires or
wires contacting any high wattage resistors. Check that all control knobs,
shields, covers, grounds, and mounting hardware have been replaced. Be
sure to replace all insulators and restore proper lead dress.

SAFETY CHECKS  FIRE AND SHOCK HAZARD

Cold Leakage Checks for Receivers with Isolated Ground

Unplug the AC cord, connect a jumper across the plug prongs, and turn
the power switch on (if applicable). Use an ohmmeter to measure the
resistance between the jumped AC plug and any exposed metal cabinet
parts such as antenna screw heads, control shafts, or handle brackets.
Exposed metal parts with a return path should measure between 1M
ohms and 5.2M ohms. Parts without a return path must measure infinity.

Hot Leakage Current Check

Plug the AC cord directly into an AC outlet. DO NOT use an isolation
transformer. Use a 1500 ohms, 10W resistor in parallel with a .15µF
capacitor to connect between any exposed metal parts on the receiver and
a good earth ground. (See figure below.) Use an AC voltmeter with at
least 5000 ohms per volt sensitivity to measure the voltage across the
resistor. Check all exposed metal parts and measure voltage at each point.
Voltage measurements should not exceed .75VAC, 500µA. Any value
exceeding this limit constitutes a potential shock hazard and must be
corrected. If the AC plug is not polarized, reverse the AC plug and repeat
exposed metal part voltage measurement at each point.

INDEXINDEX

INDEX

INDEXINDEX

SET 5303

GridTrace Location

Main Board ....................................... 3

Comb Filter Board ............................3

Important Parts Information ..................... 4

Miscellaneous Adjustments ..................... 1

Parts List ...................................................4

Placement Chart ....................................... 1

Safety Precautions .................................... 1

Schematic Component Location ..............1

Schematic Notes .......................................2

Schematics

Audio ................................................. 3

CRT ................................................... 2

Power Supply .................................... 2

System Control .................................. 2

Television .......................................... 2

Video Switching/Comb Filter ...........3

Service Mode Chart ................................. 1

Test Equipment.........................................3

Tuner Information ....................................1

5303

Technical Service Data

RCA

Model 27V412T (Chassis M134C)

Representative Model

Essential coverage

for servicing a television receiver...

 Schematics

The listing of any available replacement part herein in no case constitutes a recommendation, warranty, or guarantee by
SAMS Technical Publishing, LLC as to the quality and suitability of such replacement part. The numbers of the listed parts
have been compiled from information furnished to SAMS Technical Publishing, LLC by the manufacturers of the specific
type of replacement part listed.

Reproduction or use, without express permission, of editorial or pictorial content, in any manner, is prohibited. No patent
liability is assumed with respect to the use of the information contained herein.

© 2007 SAMS Technical Publishing, LLC

9850 E. 30th St.
Indianapolis IN 46229
www.samswebsite.com

Printed in the United States of America 5 4 3 2 1 07PF03424

Page 1 SET 5303

!IBCGC|05303U

5303

MODEL 27V412T (CHASSIS M134C)

For a Complete List of Manuals,

Visit www.samswebsite.com

RCA

 Component locations

 Parts list

Coverage includes these additional models and chassis:

Models Chassis

24V412T M134C
27V412TYX1 M134C
27V412TYX3 M134C
27V412TYX5 M134C
27V412TYX8 M134C

OCTOBER 2007 SET 5303

5303

4

Page 1 SET 5303

MISCELLANEOUS ADJUSTMENTS

HIGH VOLTAGE TEST

High voltage must not be higher than 31.8kV at any beam current.

X RAY PROTECTION TEST

Tune the set to receive a crosshatch signal. Apply an external power supply
to the positive lead of C249 (observe polarity). Slowly increase the voltage
from the supply. The set must shut down and remain off when the voltage
reaches 30V.

B+

Tune the set to receive a crosshatch signal, set the preset picture mode to
normal, and adjust VR802 for 130V ±0.5V at the positive lead of C422.

RF AGC

The RF AGC is factory preset at the time of manufacture for optimum
operation over a wide range of RF signal input conditions and should not
need readjustment, unless there is cable TV adjacent channel interference
or picture bending or channel 6 color beats because of excessive RF signal
input, this can occur if the receiver is located too close to the transmitting
tower. The signal should be attenuated at the antenna to reduce the signal
to a satisfactory level.

NOTE: Adjusting the RF AGC to extreme limits of its parameters unusu­ally provides a poor signal to noise ratio.

SCREEN

Tune the set to receive a crosshatch signal, set the preset picture mode to
normal and set all of the picture controls (brightness, contrast, etc) to
midrange. Enter the service mode and preset the menu 1 values. Set RC,
GC, and BC to 80, GD and BD to 40. While still in the service mode, press
the input button on the remote and the vertical will collapse. Adjust the
screen control to produce a dim horizontal line on the CRT.

COLOR TEMPERATURE

Test point Display
Adjust: Menu 1 RC Red Cutoff

Menu 1 GC Green Cutoff
Menu 1 BC Blue Cutoff
Menu 1 GD Green Drive
Menu 1 BD Blue Drive

Set color picture temperature to normal and set all of the picture controls
(brightness, contrast, etc) to midrange. Tune the set to receive a gray scale
stairstep test pattern. Enter the service mode and adjust the values for
cutoff and drive controls to obtain proper color tracking, no tinting of black
and white and shades of gray, and color temperature is 9300 degrees - X =
284, Y = 299.

SUB BRIGHTNESS

Tune the set to receive a gray scale stairstep signal from the A/V inputs. Set
picture color temperature to normal, Set all of the picture controls
(brightness, contrast, etc) to midrange. Enter the service mode and select
menu 5. Adjust the value of BRTC sub brightness to just light the second
dark bar, making sure the first bar stays black.

Test point Display
Adjust: Menu 3 HPOS6 H Position

Menu 3 PARA6 H Parabola
Menu 3 TRAP6 H Trapazoid
Menu 3 HSIZE6 H Size
Menu 3 CNRT6 H Corner Top
Menu 3 CNRB6 H Corner Bottom
Menu 2 HIGHT6 Height
Menu 2 VLIN6 Linearity
Menu 2 VP60 Vertical Center
Menu 2 VSC6 Vert S Correct

NOTE: Confirm correct convergence and purity before adjusting geometry.

Tune the set to receive a circular test pattern to make visual geometry
adjustments. Enter the service mode. Adjust menu 2 and menu 3 values for
the least amount of geometric distortion approximately 7% overscan.

SERVICE MODE

NOTE: Pressing the 1 and input buttons on the remote will shut the set
down if you are in the service mode.

To enter the service mode, press and hold the volume down button on the
set while pressing the info/del button on the remote. Menus 1 thru 10 can
be accessed directly using the remote keypad number buttons. For menu 11
press the 1 and notepad buttons on the remote; menu 12 press the 1 and
caps buttons on the remote; menu 13 press 1 and info/del buttons on the
remote; menu 14 press 1 and sleep buttons on the remote; menu 15 press 1
and calendar buttons on the remote; 16 press 1 and insert buttons on the
remote; menu 17 press 1 and FAV buttons on the remote; menu 18 press 1
and go back buttons on the remote. If any of the service mode menu items
have been adjusted, press the sound button to save the settings, and exit the
service mode.

ITEM SETTING

Menu 1

FAC01
RC 76
GC 86
BC 7B
GD 33
BD 2E

Menu 2

FAC02
HIGHT6 19
VP60 07
VLIN6 0A
VSC6 0A
VBLK6 0A
VCEN6 2B

Menu 3

FAC03
HPOS6 13
PARA6 1C
TRAP6 22
HSIZE6 1F
CNRT6 0A
CNRB6 09
VEHT6 03
HEHT6 03

Menu 4

FAC04
CNTX 7F
CNTN 08
BRTX 20
BRTN 20
COLX 35
COLN 00
TNTX 30
TNTN 30

Menu 5

FAC05
BRTC 3C
COLC 23
COLP 00
SCOL 07
SCNT 06
CNTC 4C
TNTCT 37
TNTCV 37

SERVICE MODE CHART

ITEM SETTING

Menu 6

FAC06
ST3 20
SV3 20
SV4 19
SVD 19
ASSH 07
SHPX 10
SHPN 2A

Menu 7

FAC07
MOD1 60
MOD2 B0
MOD3 70
OPT 36
OPTM1 C1
OPTM2 00
HDCNT 00
HSTOP FF

Menu 8

FAC08
RFAGC 26
BRTS 00
OSD 21
OSDF 53
CCD OSD 4A
CCD OSDF 65
TXCX 1F
RGCN 16

Menu 9

FAC09
V01 46
V25 5A
V50 65
V100 7F
VOLMAX 32
CURTCEN A5
GATE 2A
VOL-OUT 73

Menu 10

FAC10
MODE4 22
MODE5 0B
MODE6 1E
MODE7 C4
MODE8 2D
MODE8 C2

ITEM SETTING

Menu 11

FAC11
MPB STR 43
MPB HMC 0D
MPB HP 07
MPB LP 11
MPB LIM 00
SUB FRE 28
SUB HP 02
VOL MAI 00

Menu 12

FAC12
SVM 05
SVM1 05
OSD2 20
OSDF2 64
PYNX 28
PYNN 18
PYXS 22
PYNS 10

Menu 13

FAC13
CLTM 4F
CLVO 48
CLVS 4F
ABL 27
DCBS 12
FLGO 82
FLG1 0D

Menu 14

FAC14
HAFC 09
AGCC 1C
NOIS 01
ONTM 08
NSHP 1A
PVLVL 80
PLMT 80

ITEM SETTING

Menu 15

FAC15
RC-C FC
GC-C 02
BC-C 00
GD-C FD
BD-C 0A

Menu 16

FAC16
RC-W 04
GC-W 01
BC-W 02
GD-W FB
BD-W E7
YUVGC F7
YUVBC 08

Menu 17

FAC17
D-COL 32
D-BRI 32
D-CON 5A
D-SHP 32

Menu 18

FAC18
S-COL 32
S-BRI 32
S-CON 4B
S-SHP 32

SET 5303 Page 1

TUNER INFORMATION

TUNER VOLTAGE CHART

Pin Voltage

(1) AGC 1.8V
(2) VT 0V
(3) GND 0V
(4) SCL 4.0V
(5) SDA 4.4V
(6) VCC 4.8V
(7) VCC 4.8V
(8) NC 0V
(9) 33V 33.0V
(10) NC 0V
(11) IF1 0V

NOTE: Voltages do not change

on different bands.

TUNER TERMINAL GUIDE

(1)

(2)

(3)

(4)

(5)

(6)

(7)

(8)

(9)

(10)

(11)

SCHEMATIC COMPONENT LOCATION GUIDE

C008 E26

C01 B17

C021 C24

C022 C24

C025 B24

C026 C23

C027 C26

C028 B23

C029 B24

C030 D26

C031 C26

C032 C26

C033 B26

C034 B26

C041 B26

C043 B26

C070A B25

C101 C4

C104 A23

C105 B1

C106 B1

C107 B2

C108 C3

C109 B3

C209 D16

C210 D16

C211 D15

C211 D15

C212 D15

C213 C10

C214 C11

C216 C12

C217 C11

C218 C13

C219 C12

C220 C12

C221 B4

C223 B5

C224 C6

C225 C6

C226 C5

C227 C5

C228 B5

C229 B8

C230 D2

C231 E2

C233 C6

C234 C6

C235 C14

C236 D3

C237 D3

C238 B9

C239 B10

C241 B10

C242 B9

C243 B10

C244 D1

C245 D1

C246 D4

C247 D1

C248 D1

C249 E15

C250 C12

C251 C11

C254 A7

C260 C22

C261 C24

C262 C24

C263 D23

C264 D24

C266 A23

C280 C14

C281 C14

C301 E23

C302 D7

C303 E23

C304 D6

C305 D8

C306 E6

C308 E22

C309 D8

C311 E3

C315 E2

C401 E8

C402 E7

C403 E7

C411 E9

C412 E9

C413 E9

C414 E9

C415 E4

C419 D10

C422 A23

C431 E22

C432 E24

C433 E21

C435 E21

C441 E22

C442 E23

C443 E15

C451 E13

C501 A30

C502 C30

C503 B30

C504 E23

C505 C31

C506 C24

C508 C31

C509 C24

C624 B46

C625 B46

C626 A44

C627 A44

C630 A44

C631 A44

C634 D46

C661 D45

C801 A17

C802 A18

C803 A19

C804 A19

C804A A19

C805 A19

C805A B18

C806 A20

C807 A20

C810 C19

C811 C19

C812 C19

C813 C18

C814 C19

C815 C20

C820 C21

C821 D22

C822 D22

C826 A21

C827 A22

C828 A21

C829 B19

C830 C21

C831 C22

C832 C22

C833 B23

C834 E18

C835 B17

C836 C18

C840 B20

C902 C33

C903 B34

C904 C42

C905 C42

C908 A34

C909 D41

C910 D41

C911 D24

C912 D24

C913 B34

C914 B34

C915 B44

C916 C44

C924 D33

C925 D33

C926 D35

C927 B45

C928 B45

C929 D24

C930 D24

C1001 E44

C1002 E44

C1004 A43

C1005 A43

C1006 E43

C1008 E44

C1009 E43

C1010 E43

C1011 E44

C1012 B42

C1013 B43

C1014 B42

C1015 A43

C1016 B41

C1017 D42

C1018 E42

C1019 E43

C1023 B44

C1024 C44

C1025 B42

C1031 C43

C1033 C44

C1034 C44

C1035 B42

C1036 B42

C1037 A43

C1038 A43

C1201 B36

C1202 B36

C1203 B36

C1204 B36

C1205 D24

C1206 D24

C1211 D38

C1212 D38

C1213 D39

C1214 D39

C1215 B38

C1216 C38

C1217 C38

C1218 C38

C1219 C38

C1220 B38

C1221 B38

C1222 D39

C1223 D39

C1224 D38

C1225 D38

C1229 D39

C1230 D39

C1231 B39

C1233 C39

C1234 C38

C1235 C38

C1236 B38

D001 D25

D01 B17

D02 B17

D101 A23

D202 B16

D203 C16

D204 B16

D205 C14

D206 E2

D207 C12

D208 E14

D209 E14

D210 E15

D211 C11

D212 C11

D213 C11

D214 C13

D215 D16

D262 E15

D301 D7

D303 E3

D304 E2

D309 D9

D310 D8

D410 E4

D411 E10

D412 E10

D420 E11

D431 E22

D432 E21

D441 E22

D501 C29

D502 C29

D602 D45

D810 C19

D811 C19

D811A C19

D811B C19

D812 C19

D813 C18

D820 D21

D820A D21

D820B D21

D822 A21

D822A A21

D822B A21

D823 C21

D823A C21

D823B C21

D824 B23

D826 E19

D827 C17

D828 C17

D829 C18

D834 B22

D1001A D28

DB801 A19

DEGAUSS A19

F801 A17

IC001 B27

IC101 A26

IC101 B11

IC101 B5

IC101 D1

IC201 C23

IC202 D23

IC301 D6

IC602 A47

IC801 B19

IC802 B18

IC901 A34

IC901 C36

IC1001 A43

IC1201 B38

IR001A A25

J215 D3

J603 E10

J604 E10

J1005 E42

L001 D23

L002 B25

L101 B1

L102 B3

L204 C5

L205 C12

L206 A8

L208 C6

L209 B7

L212 C11

L301 D9

L413 E10

L414 D10

L501 C23

L502 B32

L503 B32

L505 C31

L506 C31

L801 A22

L1001 E43

L1201 B36

L1211 D37

L1212 C37

L1213 D37

L1214 D37

L1215 B38

L1216 C37

L1217 D23

P800 A17

P901 B33

P901 C41

P901 C41

P902 B33

P903 A33

P903 D41

P903 D41

P904 A33

P904 A9

P904 A9

P905 B45

P905 B45

P905 D35

Q007 B23

Q008 D25

Q01 B17

Q033C D28

Q101 B3

Q202 E16

Q203 B6

Q204 B7

Q205 E15

Q208 D16

Q209 D15

Q401 E6

Q402 E14

Q411 E8

Q412 E3

Q413 E4

Q414 E4

Q501 A30

Q502 A30

Q503 C30

Q504 C30

Q505 B30

Q506 B30

Q507 C29

Q601 D45

Q602 D45

Q603 E46

Q820 B22

Q821 B22

Q822 B17

Q823 E19

Q824 E18

Q825 E18

Q901 C42

Q902 C42

Q903 D42

Q904 D42

Q911 D34

Q912 D34

Q913 B44

Q914 B44

Q917 B35

Q918 C27

Q919 C44

Q1003 B41

Q1201 B37

Q1202 B37

Q1203 B37

Q1211 C37

Q1212 E39

Q1213 E39

Q1214 C39

Q1215 C39

Q1218 B39

R001 D26

R003 E27

R004 A26

R005 E25

R006 E26

R01 B17

R02 B17

R010 D27

R023A C25

R024 C23

R024A C25

R025 A27

R025A C25

R026 B27

R026A C25

R027A D25

R030 B23

R031 D25

R032 D25

R033 D25

R033B E28

R033C D27

R0333 C25

R034 D26

R036 C26

R036A C26

R043 C27

R044 B26

R070A B25

R101 B1

R101A C1

R102 C3

R103 B3

R104 B3

R106 B2

R107 B2

R108 B2

R209 D16

R211 D15

R212 D15

R213 D16

R214 B16

R215 C15

R216 B15

R219 C12

R220 C13

R222 C4

R223 C4

R225 A7

R226 A7

R227 C5

R228 D2

R229 E2

R230 E2

R231 E2

R232 B6

R233 B7

R233A B6

R234 B7

R235 B8

R238 D3

R239 C14

R241 D3

R242 B10

R243 B10

R244 D1

R245 D5

R246 D1

R247 D5

R248 B10

R250 E16

R251 E15

R253 E15

R254 E2

R255 E2

R256 E2

R257 E2

R258 B8

R261 E15

R262 C12

R266 A22

R302 D6

R303 D6

R304 D8

R309 D8

R310 D8

R311 D6

R312 D6

R313 D7

R316 E3

R401 E6

R402 E7

R404 E7

R412 E3

R413 E4

R414 E4

R415 E4

R416 E4

R417 E4

R418 E3

R419 D10

R420 E4

R420A E4

R422 D11

R431 E22

R432 E14

R433 E21

R453 E13

R460 E23

R461 A32

R501 A29

R502 A29

R503 A30

R505 C29

R506 C30

R508 C30

R509 C29

R510 B29

R511 B30

R513 B30

R514 D29

R515 C29

R516 B30

R517 C30

R518 A30

R519 A31

R520 C31

R521 B31

R522 D29

R605 D46

R605A D46

R606 D45

R608 A44

R610 D46

R611 B46

R612 A44

R618 E46

R656 D44

R801 A17

R810 B19

R811 B18

R812 C18

R813 C20

R814 C19

R815 C19

R816 D20

R820 D21

R821 A21

R823 C21

R825 D22

R826 B22

R827 B22

R828 E19

R829 B22

R830 C18

R831 B17

R832 E18

R833 C17

R834 C17

R834A C17

R834B C17

R835 C17

R836 E19

R837 E18

R838 E17

R840 B20

R901 C33

R902 B34

R903 B34

R904 C41

R905 A34

R906 C41

R908 A33

R910 D41

R911 D42

R912 D41

R913 D42

R914 B10

R915 A10

R916 C42

R917 C42

R920 D23

R923 D35

R924 B45

R925 B45

R926 B45

R929 C45

R930 D34

R931 D35

R932 B33

R932A D33

R933 D33

R934 B34

R934A D23

R935 D34

R936 D34

R937 D34

R944 C44

R945 C27

R946 B33

R946A B34

R947 B35

R948 B35

R951 D41

R952 D41

R953 C42

R954 C42

R1001 B42

R1002 B42

R1004 D43

R1005 B42

R1006 B41

R1007 B41

R1010 C44

R1011 C44

R1022 B43

R1023 B43

R1201 B36

R1202 B36

R1203 B36

R1204 B37

R1205 B37

R1206 B37

R1207 B37

R1208 B37

R1209 B38

R1211 C38

R1212 C38

R1213 C39

R1215 E39

R1216 E39

R1217 E38

R1218 E39

R1219 E38

R1220 C39

R1221 C39

R1228 B39

R1229 B39

R1232 E39

R1233 C40

R1234 C40

R1236 B37

R1237 B37

RL01 A18

RL01 B18

RT801 A18

RT802 A20

S002A C25

S003A C25

S004A C25

S005A D25

S006A D25

S008 C25

S501 A32

S501 B31

S501 B31

S501 B31

S501 B31

S501 C31

S501 C31

T401 E7

T402 D12

T402 D21

T801 A17

T802 A18

T803 A20

TU101 B2

V801 B32

VR802 C17

W601 A48

W602 B48

X001 C26

X201 B7

X202 A7

X1001 E44

Z101 B3

RCA MODEL 27V412T (CHASSIS M134C)

SET 5303 Page 1

Page 2 SET 5303