Sony Trinitron KV-27TW77 User manual

Television system
Channel coverage
Picture tube
Antenna
~—
KV-27TW77/271W78
__KV-32TW77/32TW78
SERVICE
MANUAL
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KV-27TW77/27TW78 | KV-27TS29/27TS32/27TS36
KV-32TW77/32TW78 | KV-32TS36/32TS46
KV-2970RS /2970M/2975M
SPECIFICATIONS
American TV standards Input
VHF: 2-13
UHF: 14-69
Cable TV: 1-125
Hi-Black Trinitron® tube
27-inch picture measured diagonally
29-inch picture tube measured
diagonally (KV-27TW77/27TW78)
32-inch picture measured diagonally
34-inch picture tube measured ~
diagonally (KV-32TW77/32TW78) Output
75-ohm external antenna terminal for ;
VHF/UHF .
2
RM-Y118
US Model
KV-27TW/77 Chassis No. SCC-F84F-A
KV-27TW78 Chassis No. SCC-F84G-A.
KV-32TW/77 Chassis No. SCC-F84J-A
KV-32TW/78 Chassis No. SCC-F84K-A
AA- 1 CHASSIS
MODELS OF THE SAME SERIES .
VIDEO and S VIDEO
S VIDEO IN (S terminal)
Y: 1 Vp-p, 75-ohms unbalanced,
sync negative
C:.0.286 Vp-p (Burst signal),
75-ohms
Video (phono jacks): 1 Vp-p,
75-ohms unbalanced, sync
negative
Audio (phono jacks): 500 mVrms
(100% modulation)
Impedance: 47 kilohms
AUDIO OUT (phono jacks) .
More than 408 mVrms at the
maximum volume setting (variable)
More than 408 mVrms (fix)
impedances: 5 kilohms
— Continued on next page —
TRINITRON© COLOR TV
SONY.

KV-27TW7H/27TW78
KV-32TW7 W32TW73
-Y118
-
Speaker
output
5Wx2
Supplied
accessories
: . am - Remote Commander RM-Y118(1) with 1
Audio
frequency
response:
Front
80
Hz
—
20
kHz
size
AA
(R6)
EVEREADY
battery
Power
requirements
120
V
AC,
60
Hz
:
:
Recommended
accessories
Power
consumption
UN
mixer
EAC-66
:
;
Connecting
cable
KV-27TW77
170
W
VMC-810S/820S,
VMC-720M,
KV-27TW78
170
W
YC-15V/30V,
RK-74A
ese
[sw
Design and specifications are subject to change without
KV-32TW78 195 Ww notice.
standby mode 5W
Dimensions/Weight
ioe =e well Dimensions (w/h/d) - Weight
KV-27TW77 750 x 1041 x 655 mm 83.6 kg
(295/a x 41 x 257 in.) (184 Ibs)
KV-27TW78 750 x 1041 x 655 mm 83.6 kg
(29%/s x 41 x 25% in.) "(184 Ibs)
~ | KV-32TW77 895 x 1117 x 700 mm 108.6 kg
(35'/4 x 44 x 27% in.) (239 lbs)
KV-32TW78 895 x 1117 x 700 mm 108.6 kg |
; (354 x 44 x 275s in.) (239 Ibs)
7
(CAUTION)
SHORT CIRCUIT THE ANODE OF THE PICTURE TUBE AND THE
ANODE CAP TO THE METAL CHASSIS, CRT SHIELD, OR CARBON
PAINTED ON THE CRT, AFTER REMOVING THE ANODE.
WARNING!!!
AN ISOLATION TRANSFORMER SHOULD BE USED DURING ANY -
SERVICE TO AVOID POSSIBLE SHOCK HAZARD, BECAUSE OF
LIVE CHASSIS.
THE CHASSIS OF THIS RECEIVER IS DIRECTLY CONNECTED TO
THE AC POWER LINE.
SAFETY-RELATED COMPONENT WARNING!!
COMPONENTS IDENTIFIED BY SHADING AND MARK A, ON THE
SCHEMATIC DIAGRAMS, EXPLODED VIEWS 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
PUBLISHED BY SONY. CIRCUIT ADJUSTMENTS THAT ARE
CRITICAL TO SAFE OPERATION ARE IDENTIFIED IN THIS MANUAL.
FOLLOW THESE PROCEDURES WHENEVER CRITICAL
COMPONENTS ARE REPLACED OR IMPROPER OPERATION IS
SUSPECTED. :

| KV-27TW77/27TW78
KV-32TW7 M32T
W778
M-Y118
SAFETY CHECK-OUT
(US Model Only)
After corrécting the original service problem,
perform the following safety checks before releasing
the set to the customer:
1. Check the area of your repair for unsoldered or
poorly-soldered connections. Check the entire
board surface for solder splashes and bridges.
2. Check the interboard wiring to ensure that no
wires are “pinched” or contact high-wattage
resistors.
3. Check that all control knobs, shields, covers,
ground straps, and mounting hardware have
been replaced. Be absolutely certain that you
have replaced all the insulators.
4. Look for unauthorized replacement parts, par-
ticularly transistors, that were installed during a
previous repair. Point them out to the customer
and recommend their replacement.
5. Look for parts which, though functioning, show
obvious signs of deterioration. Point them out
to the customer and recommend their replace-
ment.
6. Check the line cord for cracks and abrasion.
Recommend the replacement of any such line
cord to the customer.
7. Check the condition of the monopole antenna
(if any).
Make sure the end is not broken off, and has
the plastic cap on it. Point out the danger of
impalement on a _ broken antenna to the
customer, and recommend the antenna’s
replacement.
8. Check the B+ and HV to see they are at the
values specified: Make sure your instruments
are accurate; be suspicious of your HV meter
if sets always have low HV.
9. Check the antenna terminals, metal trim,
“metallized” knobs, screws, and all other
exposed metal parts for AC leakage. Check
leakage as described below.
To Exposed Metal
Parts on Set
AC
voltmeter
| | (0.75 V)}
= Earth Ground
Using an AC voltmeter to check AC leakage.
LEAKAGE TEST *
The AC leakage from any exposed metal part to
earth ground and from all exposed metal parts to any
exposed metal part having a return to chassis, must
not exceed 0.5mA (500 microampers).
current
methods.
Leakage
can be measured by any one of three
1. A commercial leakage tester, such as the
Simpson 229 or RCA WT-540A. Follow the
manufacturers’ instructions to use these instru-
ments.
2. <A battery-operated AC milliammeter. The Data
Precision 245 digital multimeter is suitable for
this job.
3. Measuring the voltage drop across a resistor by
means of a VOM or battery-operated AC volt-
meter. The “limit” indication is 0.75V, so
analog meters must have an accurate low-
voltage scale. The Simpson 250 and Sanwa
SH-63Trd are examples of a passive VOM that
is suitable. Nearly all battery operated digital
multimeters that have a 2V AC range are
suitable. (See Fig. A)
HOW TO FIND A GOOD EARTH GROUND
A cold-water pipe is guaranteed earth ground; the
cover-plate retaining screw on most AC outlet boxes is
also at earth ground. If the retaining screw is to be
used as your earth-ground, verify that it is at ground
by measuring the resistance between it and a cold-
water pipe with an ohmmeter. The reading should be
zero ohms. If a cold-water pipe is not accessible,
connect a 60—100 watts trouble light (not a neon
lamp) between the hot side of the receptacle and the
retaining screw. Try both slots, if necessary, to locate
the hot side of the line, the lamp should light at
normal brilliance if the screw is at ground potential.
(See Fig. B)
Trouble Light
Ohmmeter
Cold-water Pipe
Fig. B. Checking for earth ground.

~ KV-27TW77/27TW78
KV-32TW77/ 32Tvv78
TABLE OF CONTENTS
Section Title Page
1. GENERAL
1-1. Locating the Controls -++++++-+++eeeeee eres 5
1-2. Using the On-Screen Menus -----++++-++++++> f,
1-3. Turning the Cable Mode On or Off --------- rt 8
1-4. Presetting TV Channels ---+-++++++eeeeeereee 9
1-5. Connecting Other Equipment ---------+-+------- 11
1-6. Watching TV Programs -+++++serr reece eee 13
1-7. Using Convenient Features --+++--++++++eeseeee: 14
1-8. Using Closed Caption -++-+++++rererrereerees 14
1-9. Watching Two Pictures at Once
(Picture-in-Picture) Se i ii 15
1-10. Using the Timer-Activated Functions ---------- 18
1-11. Customizing the Screen Display --++-++++++++: 21
1-12. Using the Pre-Programmed
Remote Commander -*+++rrseceeeeeeeceeeees 23°
2. DISASSEMBLY
2-1. RearPlate Removal -++++ceseeeceeceeceeeees 24
2-2. Chassis Assy Removal -++++esessseeseeeeeeee 24
223: ‘Servide Position. #2006 82544 sewsisise den eeceieles 24
2-4. P Board and P Bracket Removal «+++++++++++s 24
2-5. UABoard Removal -cscrcccccesceseseceeeees 25
2-6. Extension Cable ---+-+secccce eee eeeeeeeeeeee 25
2-7. Picture Tube Removal (1)
(KV-27TW77/27TW78 only) -+++rercteee cee 26
Picture Tube Removal (2)
(KV-32TW77/32TW78 only) s+++rre rte re eee 27
2-8. Repair of Chip Component Circuit Board -:++:-- 28
3. SET-UP ADJUSTMENTS
3-1. Beam Landing -+++++seeereeeeeeee cere eeeees 33
3-2. Convergence --+++s+ssseeeee eee e rece eeeees 34
3-3. Focus Adjustment -++++++esssseeeeeeeee cease 37
3-4. G2 (Screen) and White Balance Adjustments ---- 38
Section Title Page
4. SAFETY RELATED ADJUSTMENTS .-.-.----- 39
5. CIRCUIT ADJUSTMENTS
5-1. Electrical Adjustment by Remote Commander --- 41
5-2. M Board Adjustments eee tee ewe en eta ence nne 43
5-3. P Board Adjustments ee ee ee eee 46
6. DIAGRAMS
6-1. Block Diagrams ----+++++rcte errr eee eeeeete 47
6-2. Frame Schematic Diagram --++++++++++s+++eee 57
6-3. Circuit Boards Location «++++++++ssreeetrreee 60
6-4. Schematic Diagrams and Printed Wiring Boards
(1) Schematic Diagram of D Board -+++++++++++++> 61
(2) Schematic Diagram of A, EandH Boards -:--:- 69
(3) Schematic Diagram of UA Board +++++-+++++- 73
(4) Schematic Diagram of P Board -+++++++++++++: 83
(5) Schematic Diagram of M Board -+-+++++++++++ 87
(6) Schematic Diagram of C Board ++-+++++++-+++: 94
6-5. Semiconductors -++eses scree cert eens eneeeees 96
7. EXPLODED VIEWS
FAs: ‘Chassis: és0s8s60 ei dead ede eeded ese Peet 97
FD” ACQVEE > ahs waa os Oe Oe Pew Nie ea gale heres 98
73- Dioture Tube. :ecesessineescseeteeet te ebuesns 99
8. ELECTRICAL PARTS LIST ..-------------- 100

SECTION 1
GENERAL
The operating instructions mentioned here are partial abstracts from
the Operating Instruction Manual. The page numbers of the
Operating Instruction Manual remein as in the manual.
1-1.
LOCATING
THE
CONTROLS
SL a rE TEN Pa TI aD,
Screen Displays
For details, see the pages indicated by the numbered black circles @.
Channe! number display
Main picture input mode
On-screen
menu
displays
SLEEP,
MUTING
displays
©
®-9090 -9 0-4
CHANNEL CAPTION display
®@-@
MTS mode (MAIN, SAP or
MONO) @
Bar display for volume,
picture or sound adjustment
®@ -@
CURRENT TIME dispiay:
Picture-in-Picture input mode
KV-27TW77/27TW78/32TW77/
32TW78 only)
6 Pretace
Front Panel
* Buttons with ihe same function are
also located on the Remote
Commander (pp. 10 — 11).
** If you press this button, functions
and menues are displayed one by one.
Press any button to stop DEMO.
KV-27TW77_ KV-32TW77
KV-27TW78 KV-32TW78
AV input jack door
a OA
Pull the
door open
VIDEO 2/INPUT jacks
TIMER/STAND BY indicator
STEREO indicator
POWER button*
CHANNEL +/- buttons*
VOLUME +/— buttons*
TV/VIDEO button*
DEMO button**
Remote control detector
Preface 7
AA
<<
QN
NN
44
$3
NIN
NN
14
38
WN
000
SLLA-WHY