Sharp 25VT-J100 User manual

25VT-J100
25VT-CJ10
1
CONTENTS
In the interests of user-safety (Required by safety regulations in some countries ) the set should be restored to its
original condition and only parts identical to those specified should be used.
Page
æIMPORTANT SERVICE SAFETY PRECAUTION ....................................................................................2
æELECTRICAL SPECIFICATIONS............................................................................................................. 6
æLOCATION OF USER’S CONTROL......................................................................................................... 7
æDISASSEMBLYAND REASSEMBLY....................................................................................................... 9
æINSTALLATIONAND SERVICE INSTRUCTIONS .................................................................................12
æPRECAUTIONS IN REASSEMBLING (Refer to 13VT-J100 Service Manual)
æFUNCTIONOF MAJOR MECHANICALPARTS (Refer to 13VT-J100 Service Manual)
æADJUSTMENT, REPLACEMENT AND ASSEMBLY OF MECHANICAL UNITS
(Referto13VT-J100ServiceManual)
æADJUSTMENT OFTHE VCR ELECTRICAL CIRCUITRY (Refer to 13VT-J100 Service Manual)
æTROUBLESHOOTING (Refer to 13VT-J100 Service Manual)
æTROUBLESHOOTING OF TV SECTION............................................................................................... 17
æCHASSIS LAYOUT ................................................................................................................................ 20
æBLOCK DIAGRAM OF TV SECTION.....................................................................................................23
æBLOCK DIAGRAM OF VCR SECTION (Refer to 13VT-J100 Service Manual)
æOVERALL SCHEMATIC......................................................................................................................... 27
æDESCRIPTION OF SCHEMATIC DIAGRAM ......................................................................................... 31
æPRINTED WIRING BOARD ASSEMBLIES ............................................................................................ 45
æREPLACEMENT PARTS LIST ............................................................................................................... 51
æPACKING OF THE SET ......................................................................................................................... 70
SERVICE MANUAL
TV/VCR COMBINATION
Chassis No. VN-71
SHARP ELECTRONICS CORPORATION
Service Headquarters: Sharp Plaza, Mahwah, New Jersey 07430-2135
SHARP ELECTRONICS OF CANADA LTD.
335 Britannia Road East Mississauga, Ontario L4Z 1W9 Canada
MODELS
25VT-J100
25VT-CJ10
S67A825VT-J10

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SERVICING OF HIGH VOLTAGE SYSTEM
AND PICTURE TUBE
When servicing the high voltage system, re-
move the static charge by connecting a 10k
ohmresistorin series withaninsulated wire
(such as a test probe) between the picture
tube ground and the anode lead. (AC line
cord should be disconnected from AC out-
let.)
1. Note that the picture tube in this receiver employs
integral implosion protection.
2. Replace with tube of the same type number for
continued safety.
3. Do not lift picture tube by the neck.
4. Handle the picture tube only when wearing
shatterproof goggles and after discharging the high
voltage anode completely.
CAUTION: FOR CONTINUED
PROTECTION AGAINST A
RISKOF FIRE, REPLACE
ONLY WITH SAME TYPE 4A-
125V FUSE.
4A 125V
IMPORTANT SERVICE SAFETY PRECAUTION
Service work should be performed only by qualified service technicians who are thor-
oughly familiar with all safety checks and servicing guidelines which follow:
WARNING
1. For continued safety, no modification of any circuit
should be attempted.
2. Disconnect AC power before servicing.
3. Semiconductor heat sinks are potential shock
hazards when the chassis is operating.
4. The chassis in this receiver has two ground systems
whichareseparated by insulation material.The non-
isolated (hot) ground system is for the B+ voltage
regulator circuit and the horizontal output circuit.The
isolatedgroundsystemisforthelow B+ DC voltages
and the secondary circuit of the high voltage
transformer.
To prevent electrical shock use an isolation
transformer between the line cord and power
receptacle, when servicing this chassis.
X-RADIATION AND HIGH VOLTAGE LIMITS
1. Be sure all service personnel are aware of the
proceduresand instructionscoveringX-radiation.The
only potential source of X-ray in current solid state
TVreceiversisthepicturetube.However,thepicture
tubedoesnotemitmeasurableX-Rayradiation if the
high voltage is as specified in the "High Voltage
Check" instructions.
It is only when high voltage is excessive that X-
radiation is capable of penetrating the shell of the
picture tube including the lead in glass material. The
importantprecaution istokeep thehighvoltagebelow
the maximum level specified.
2. It is essential that servicepersonal have available at
all times an accurate high voltage meter.
The calibration of this meter should be checked
periodically.
3. Highvoltageshouldalwaysbe kept at theratedvalue
−no higher. Operation at higher voltages may cause
a failure of the picture tube or high voltage circuitry
and; also under certain conditions, may produce
radiation excess specitications.
4. Whenthehighvoltageregulatoris operating properly
thereis nopossibilityof anX-radiationproblem.Every
time a color chassis is serviced, the brightness
should be tested while monitoring the high voltage
with a meter to be certain that the high voltage does
notexceedthe specified valueandthatitis regulating
correctly.
5. Do not use a picture tube other than that specified or
make unrecommended circuit modifications to the
high voltage circuitry.
6. Whentroubleshootingand takingtestmeasurements
ona receiverwithexcessivehigh voltage,avoidbeing
unnecessarily close to the receiver.
Donot operate the receiver longer than isnecessary
to locate the cause of excessive voltage.

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BEFORE RETURNING THE RECEIVER
(Fire & Shock Hazard)
Before returning the receiver to the user, perform
the following safety checks.
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SAFETY NOTICE
Many electrical and mechanical parts in television
receivers have special safety-related characteristics.
These characteristics are often not evident from visual
inspection, nor can protection afforded by them be
necessarilyincreased byusingreplacement components
rated for higher voltage, wattage, etc.
Replacement parts which have these special
safety characteristics are identified in this manual;
electricalcomponents havingsuchfeaturesare identified
by " å" and shaded areas in the Replacement Parts
Lists and Schematic Diagrams.
1.5k ohm
10W
0.15µF
TEST PROBE
TO EXPOSED
METAL PARTS CONNECT TO
KNOWN EARTH
GROUND
1. Inspect all lead dress to make certain that leads are
not pinched or that hardware is not lodged between
the chassis and other metal parts in the receiver.
2. Inspect all protective devices such as non-metallic
control knobs, insulating materials, cabinet backs,
adjustment and compartment covers or shields,
isolation resistor-capacity networks, mechanical
insulators, etc.
3. To be sure that no shock hazard exists, check for
leakage current in the following manner.
»Plug the AC cord directly into a 120 volt AC outlet,
using reverse polarity (Do not use an isolation
transformer for this test).
»Using to clip leads, connect a 1.5k ohm, 10 watt
resistor paralleled by a 0.15µF capacitor in series
with all exposed metal cabinet parts and a known
earth ground, such as electrical conduit or electrical
ground connected to earth ground.
»Use anAC voltmeter having with 5000 ohm per volt,
orhigher, sensitivity to measure the AC voltage drop
across the resistor.
For continued protection, replacement parts must be
identical to those used in the original circuit. The use of
a substitute replacement parts which do not have the
samesafety characteristics asthefactoryrecommended
replacement parts shown in this service manual, may
create shock, fire, X-radiation or other hazards.
AC
VOLTMETER
IMPORTANT SERVICE SAFETY PRECAUTION
(Continued)
»Connect the resistor connection to all exposed metal
parts having a return to the chassis
(antenna, metal cabinet, screw heads, knobs and
controlshafts,escutcheon,etc.)andmeasuretheAC
voltage drop across the resistor.
AII check must be repeated with the AC line cord
plug connection reversed. (IF necessary, a non-
polarized adapter plug must be used only for the
purpose of completing these check.)
Anycurrentmeasuredmust not exceed 0.5 milliamp.
Any measurements not within the limits outlined
above are indicative of a potential shock hazard and
corrective action must be taken before returning the
instrument to the customer.

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PRECAUTIONS A PRENDRE LORS DE LA REPARATION
Ne peut effectuer la réparation qu' un technicien spécialisé qui s'est parfaitement
accoutumé à toute vérification de sécurité et aux conseils suivants.
LIMITES DES RADIATIONS X ET DE LA
HAUTE TENSION
1. Tout le personnel réparateur doit être instruit des
instructions et procédés relatifs aux radiations X.
Le tube-image, seule source de rayons X dons les
téleviseurs transistorisés, n'émet pourtant pas de
rayonsmesurablessila haute tension est maintenue
à un niveau préconisé dans la section "Vérification
de la haute tension".
C'estseulement quand lahautetensionest excessive
que les rayons X peuvent entrer dans l'enveloppe du
tube-image y compris le conducteur de verre. Il est
important de maintenir la haute tension en-dessous
du niveau spécifié.
2. Il est essentiel que le réparateur ait sous la main un
voltmètreà hautetensionquidoit êtrepériodiquement
étalonné.
3. La haute tension doit toujours être maintenue à la
valeurderégime-etpasplushaute.L'opération à des
tensions plus élevées peut entraîner une panne du
tube-image ou du circuit à haute tension et, dans
certaines conditions, peut entraîner une radiation
dépassant les niveaux préscrits.
4. Quand le régulateur à haute tension fonctionne
correctement, il n'y a aucun problème de radiation
X. Chaque fois qu'un châssis couleurs est réparé, la
luminosité doit être examinée bout en contrôlant la
haute tension à l'aide d'un voltmètre pour s'assurer
que la haute tension ne dépasse pas la valeur
spécifiée et qu'elle soit correctement réglée.
5. Nepasutiliseruntube-imageautreque celui spécifié
et ne pas effectuer de modifications déconseillées
du circuit à haute tension.
6. Lors de la recherche des pannes et des mesures
d'essai sur un récepteur qui présente une haute
tension excessive, éviter de s'approcher inutilement
du récepteur.
Ne pas faire fonctionner le récepteur plus longtemps
que nécessaire pour localiser la cause de la tension
excessive.
AVERTISSEMENT
1. N'entreprendre aucune modification de tout circuit.
C'est dangereux.
2. Débrancher le récepteur avant toute réparation.
3. Les déversoirs thermiques à semi-conducteurs
peuvent présenter un danger de choc électrique
lorsque le réceqteur est en marche.
4. Lechâssisdecerécepteuradeux systèmes de mise
à la terre qui sont séparés par un matériau isolant.
Lesystème de mise à la terrenon-isolée (chaud)est
pourlecircuitdurégulateurdetension B+ et le circuit
de sortie horizontale. Le système de mise à la terre
isoléest pourlesbassestensions C.C.B+et lecircuit
secondaire du transformateur de haute tension.
PRECAUTION:POUR LA
PROTECTION CONTINUE
CONTRE LES RISQUES
D'INCENDIE, REMPLACER LE
FUSIBLEPARUN FUSIBLE DE
MEME TYPE 4A-125V.
4A 125V
REPARATION DU SYSTEMEAHAUTE TEN-
SION ET DU TUBE-IMAGE
Lors de la réparation de ce systéme,
supprimer la charge statique en branchant
une résistance de 10 k en série avec un fil
isolé (comme une sonde d'essai) entre la
mise à la terre du tube-image et le fil
d'anodel.(Lecorden d'alimentation doit être
retiré de la prise murale.)
1. Il est à noter que le tube-image de ce récepteur est
intégralement protégé contre l'implosion.
2. Par mesure de sécurité, changer le tube-image pour
un tube du même numéro de type.
3. Ne pas lever le tube-image par son col.
4. Nemanipulerletube-image qu'en porantdeslunettes
incassables et qu'après avoir déchargé totalement
la haute tension.

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AC
VOLTMETER
VERIFICATIONS CONTRE L'INCEN-DIE ET
LE CHOC ELECTRIQUE
Avant de rendre le récepteur à l'utilisateur, effectuer
les vérifications suivantes.
»Toucher avec la sonde d'essai les pièces métalliques
exposées qui présentent une voie de retour au
châssis (antenne, coffret métallique, tête des vis,
arbres de commande et des boutons, écusson, etc.)
et mesurer la chute de tension CA en-travers de la
résistance.
Toutes les vérifications doivent être refaites après
avoir inversé la fiche du cordon d'alimentation. (Si
nécessaire,une prise d'adpatationnonpolariséepeut
êtreutiliséedanslebutdeterminer ces vérifications.)
Tous les courants mesurés ne doivent pas dépasser
0,5 mA.
Dans le cas contraire, il y a une possibilité de choc
électrique qui doit être supprimée avant de rendre le
récepteur au client.
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AVIS POUR LA SECURITE
Denombreuses pièces, électriquesetmécaniques,dans
lestéléviseursprésentent des caractéristiques spéciales
relativesàlasécurité,quinesontsouventpasévidentes
à vue. Le degré de protection ne peut pas être
nécessairement augmentée en utilisant des pièces de
remplacement étalonnées pour haute tension,
puissance, etc.
Les pièces de remplacement qui présentent ces
caractéristiques sont identifiées dans ce manuel; les
pièces électriques qui présentent ces particularités sont
PRECAUTIONS A PRENDRE LORS DE LA REPARATION
(Suite)
1. Inspectertouslesfaisceauxdecâblespours'assurer
queles fils ne soient paspincés ouqu'un outilne soit
pas placé entre le châssis et les autres pièces
métalliques du récepteur.
2. Inspecter tous les dispositifs de protection comme
les boutons de commande non-métalliques, les
isolants,le dos ducoffret,les couvercles oublindages
de réglage et de compartiment, les réseaux de
résistance-capacité, les isolateurs mécaniques, etc.
3. S'assurer qu'il n'y ait pas de danger d'électrocution
en vérifiant la fuite de courant, de la facon suivante:
»Brancherlecordond'alimentation directem-ent à une
prise de courant de 120V. (Ne pas utiliser de
transformateur d'isolation pour cet essai).
»Al'aidede deux filsàpinces,brancherune résistance
de1,5kΩ10 wattsenparallèleavec un condensateur
de0,15µFen série avec toutes lespiècesmétalliques
exposées du coffret et une terre connue comme une
conduite électrique ou une prise de terre branchée à
la terre.
»Utiliser un voltmètre CA d'une sensibilité d'au moins
5000Ω/Vpourmesurerlachutedetensionentravers
de la résistance.
1.5k ohm
10W
TO EXPOSED
METAL PARTS CONNECT TO
KNOWN EARTH
GROUND
AUX PIECES
METALLIQUES
EXPOSEES
Voltmètre CA
identifiées par la marque " å" et hachurées dans la
liste des pièces de remplacement et les diagrammes
schématiques.
Pour assurer la protection, ces pièces doivent être
identiques à celles utilisées dans le circuit d'origine.
L'utilisation de pièces qui n'ont pas les mêmes
caractéristiques que les pièces recommandées par
l'usine, indiquées dans ce manuel, peut provoquer des
électrocutions, incendies, radiations X ou autres
accidents.
BRANCHER A UNE
TERRE CONNUE
0.15µF
SONDE D'ESSAI

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TV SECTION POWER INPUT: 120 V AC 60 Hz
POWER RATING: 110W
PICTURE SIZE
Width: 63.4cm
Height: 58.8cm
Depth: 51.2cm
CONVERGENCE: Magnetic
SWEEP DEFLECTION: Magnetic
FOCUS: Hi-Bi-Potential Electrostatic
INTERMEDIATE FREQUENCIES
Picture IF Carrier Frequency: 45.75 MHz
Sound IF Carrier Frequency: 41.25 MHz
Color Sub-Carrier Frequency: 42.17 MHz (Nominal)
AUDIO POWER OUTPUT RATING: 1.3W (at 10% Distortion)
SPEAKER
Size: 8cm (3")P.M.,0.34 oz. Magnet
Voice Coil Impedance: 8 ohm at 400 Hz
VHF/UHF ANTENNA INPUT IMPEDANCE: 75 ohm unbalanced
TUNING RANGES
VHF-Channels: 2 thru 13
UHF -Channels: 14 thru 69
CATV Channels: 1,14 thru 125 (EIA,Channel Plan)
VCR SECTION Format: VHS Standard
Video Recording System: Rotary Two-Head Helical Scanning
Number of Video Heads: 2 pcs.
Video Signal Standard: NTSC Color System
Tape Width: 12.7mm (1/2inch)
Tape Speed: (SP)33.35mm/sec (1.31i.p.s)
(LP)16.67mm/sec (0.66i.p.s)
Play back only
(EP)11.12mm/sec (0.44i.p.s)
Maximum Recording Time: (SP)160min (T-160)
(EP)480min (T-160)
Video Input: 0.5 to 2.0 Vp-p, 75 ohm unbalanced
Audio Input: -8dB, 47k ohm unbalanced (0 dB-0.775 Vrms)
Operating Temperature: 5°C to 40°C (41°F to 104°F)
Storage Temperature: -20°C to 60°C (-4°F to 140°F)
Specifications are subject to change without prior notice.
ELECTRICAL SPECIFICATIONS

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LOCATION OF USER'S CONTROL
Description Of Controls
FRONT
REAR

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Location Of Control’s Buttons (Remote Control)
LOCATION OF USER'SCONTROL (Continued)

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1. Remove the 6 rear cover fixing screws and detach the rear cover.
2. Take out the anode cap, CRT PWB, connectors K,M and RC, coating ground SP chip, fixing screws and others.
3. Remove the 2 main PWB fixing screws and take out the main PWB unit and the VCR unit.
4. Remove the 7 VCR fixing screws, and detach the shielding case.
DISASSEMBLY AND REASSEMBLY

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5. Remove the 4 cassette housing control fixing screws, and detach the cassette housing control.
6. Remove the 4 mechanism chassis fixing screws, and detach the mechanism chassis PWB.
7. Remove the 8 main PWB fixing screws, and detach the main PWB.
DISASSEMBLY AND REASSEMBLY (Continued)

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DISASSEMBLY AND REASSEMBLY (Continued)
For servicing any of the components inside, disconnect the lead dressing holder. Position the main PWB unit upright
as shown below and connect the leads for starting the services.
Note: Fit the VCR unit into the front cabinet with the
front flap door tilted at 70~80°.
70~80°

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INSTALLATION AND SERVICE INSTRUCTIONS
Notes: (1) When performing any adjustments to resistor controls and transformers use non-metallic
screwdriver or TV alignment tools.
(2) Before performing adjustment, TV set must be on at least 15 minutes.
CIRCUIT PROTECTION
Thereceiver isprotectedby a4.0Afuse (F701),mounted
on PWB-A, wired into one side of the AC line input.
X-RADIATION PROTECTOR CIR-
CUIT TEST
After service has been performed on the horizontal
deflection system, high voltage system, or B+ system,
test the X-radiation protector circuit to ascertain proper
operation as follows:
1. Apply 120V AC using a variac transformer for
accurate input voltage.
2. Allow for warm up and using the remote controller,
set the brightness level and contrast level to
maximum.
3. Check the voltage of test point TP653. (It’s voltage
should be about 10.3V DC.)
4. Apply external 13.3V DC at TP653 by using an
externalDCsupply,The increased voltage will cause
the horizontal oscillator to stop and the TV to shut
off.
5. To re-start the osillator, remove the external DC
power supply and short together TP651 andTP652.
Once the TV set operates normally again, remove
the short between TP651 and TP652.
HIGH VOLTAGE CHECK
High voltage is not adjustable but must be checked
to verify that the receiver is operating within safe
and efficient design limitations as specified checks
should be as follows:
1. Connect an accurate high voltage meter between
ground and anode.
2. Operate receiver for at least 15 minutes at 120VAC
line voltage, with strong air signal or properly tuned
in test signal.
3. Set to Service mode on, service item: MUTE, and
bus data 1(Y-mute on).
4. Thevoltageshouldbeapproximately 28.1kV (at zero
beam).
If a correct reading cannot be obtained, check
circuitry for malfunctioning components.
Upon completion of voltage check, readjust screen
control for proper operation and set S851 to center
position (cut off mode).

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The J-series SHARP TV/VCR COMBINATION have most of the analog setup adjustments eliminated. Coil and
variable resistor adjustments are now performed digitally by using the remote transmitter or set’s volume
and channel change function buttons.
Note: There are still a few analog adjustments in the J-series such as 120V adjust, focus, master screen
voltage and coils in the picture if/detector circuit.
Follow the steps below whenever service adjustment is required. See table “B” to determine if service
adjustments are required.
1.Service mode -
Beforeputtingunit into the service mode, check, that
customer adjustments are in the normal mode. use
the reset function in the video adjust menu to ensure
customercontrolsare in theirproper(reset) position.
To enter the service mode -
While pressing the Ch-up (S2507) button, Plug the
ACcord intoawallsocket. NowtheTVsetis switched
on and enters the service mode.
Whensuccessfullyentered, the service mode will be
displayed as shown in Figure A. The “SERVICE
MODE” figure the top line stands for service
adjustment item and data (see Figure A.).
To exit service mode-
Turn off the power or unplug the set.
2. Service item selection
Once in the service mode, press the channel up or
channel down button on the remote transmitter or at
the set.
(Table-A.) . Select the item you wish to adjust.
SERVICE MODE:01
SUB-COLOR=64
Figure A.
PICTURE:16 02
3.Data number selection
Pessthevolumeupordownbutton to adjust the data
number in the upper left hand side of the screen.

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Table-B
PART
REPLACED ADJUSTMENT
NECESSARY UNNECESSARY NOTE
IC2001 X
IC401 X
IC2101 X
CRT X
Data is stored in IC2101.
Theadjustmentisneededtocompensatefor characteristics
of parts including IC401.
Initial setting values are written from IC2001.Adjust for best
results.
Adjust items related to picture tube only.
PICTURE 16 0~63
TINT 33 0~77
COLOR 25 0~63
BRIGHT 28 0~63
SHARP 7 0~13
V-PHASE 3 0~7
H-PHASE 20 0~31
RF-AGC 31 0~63
V-AMP 18 0~63
PIF-VCO 64 0~127
R CUT-OFF 0 0~255
G CUT -OFF 0 0~255
B CUT-OFF 0 0~255
G GAIN 128 0~255
B GAIN 128 0~255
MUTE 0 0~2 "0"=Normal raster,"1"=no "2"=No Vertical
BALANCE 32 0~63
TEXT POSITION 28 0~128
TEXT PICTURE 20 0~1
CCD LEVEL 7 0~10
OPTION 1 0~3
DATA
INTIAL VALUE RANGE
Table-A
ADJUSTMENT
ITEM ADJUSTMENT COMMENTS
*No adjustment is required due to proper setting being made by IC3101 automatically.

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White balance adjustment
1. Have unit receive a good local channel.
2. Enter the service mode. select service adjustment
“COLOR” and set to “0” ( minimum color) . “COLOR”
does not have to be adjusted if you selected a B/W
picture or monoscope pattern.
3. Alternately adjust service adjustment data of “G
GAIN” and “B GAIN” untill a good grey scale with
normal whites is obtained.
4. Select service adjustment “COLOR”and adjust data
to obtain normal color level.
Sub-picture adjustment
1. Have unit receive a good local channel.
2. Make sure the customer picture control is set to
maximum.
3. Enter the service mode and select service
adjustment “PICTURE”.
4. Adjust the data value to achieve normal contrast
range.
Sub-Tint Adjustment
1. Have unit receive a good local channel.
2. Set customer tint control to center of it’s range.
3. Enter the service mode and select service
adjustment “TINT”.
4. Adjust“TINT”datavalue to obtain normalfleshtones.
Sub-color adjustment
1. Have unit receive a good local channel.
2. Make sure the customer color control is set to
center position .
3. Enter the service mode and select service
adjustment “COLOR”.
4. Adjust “COLOR”data value to obtain normal color
level.
Sub-brightness adjustment
1. Have unit receive a good local channel.
2. Make sure the customer brightness control is set to
center position.
3. Enter the service mode and select service
adjustment “BRIGHT”.
4. Adjust “BRIGHT”data value to obtain normal
brightness level.
SERVICE ADJUSTMENT
VCO Adjustment
1. Connectadigitalvoltmeter between pin(44)ofIC401
and ground.
2. Select a good local channel.
3. Enter the service mode. select adjustment “PIF-
VCO” and data value “64”.
4. AdjusttheVCOcoilT201sothatthedigital voltmeter
reads 2.5 volts.
5. Adjustment is complete, remove the voltmeter,
return to “normal” mode.
RF AGC Adjustment
1. Have unit receive a good local channel.
2. Enter the service mode and select service
adjustment “RF-AGC”.
3. Set the data value to point where no noise or beat
appears.
4. Select another channel to confirm that no noise or
beat appears.
Note 1: You will have to come out of the service
mode to select another channel.
Note 2: Setting the data to “0” will produce a
black raster.
Screen adjustment
1. Select a good local channel.
2. Enter the service mode and select service
adjustment “COLOR” and set the data value to “0”
to set the color level to minimum.You may skip this
step if you selected a B/W picture or monoscope
pattern.
3. Select service adjustment “MUTE” and adjust the
data value to “1” this turns off the luminance signal
(Y-mute) .
4. Selectserviceadjustment“BRIGHT”and adjust data
value to "28".
5. Adjustthemasterscreencontrol untill rasterdarkens
to the point where raster is barely seen.
6. Adjust service adjustments “R-CUT OFF” red,”G-
CUT OFF" green and “B-CUT OFF” blue to obtain
a good grey scale with normal whites at low
brightness level.
7. Select service adjustment “MUTE” and reset data
to”0"Selectservice adjustment “COLOR” and reset
data to obtain normal color level.
8. Remove digital voltmeter. reset master screen
control to obtain normal brightness range.

25VT-J100
25VT-CJ10
16
Vertical-size adjustment
1. Have unit receive a good local channel.
2. Enter the service mode and select service
adjustment “V-AMP”.
3. While observing the top and bottom of the screen,
adjust“V-AMP” data value to proper vertical size and
linearity.
Horizontal position adjustment
1. Have unit receive a good local channel.
2. Entertheservicemode andselectservice adjustment
“H-PHASE”.
3. Adjust “H-PHASE” data value so that picture is
centered.
Caption position adjustment (hori-
zontal)
1. Have unit receive a good local channel.
2. Entertheservicemode andselectservice adjustment
“TEXT POSITION”.
3. A black text box appears on the screen (see
Figure B.) .
4. Adjust“TEXTPOSITION”data value so that text box
is positioned in the center of the screen.
Figure B.

25VT-J100
25VT-CJ10
17
TROUBLESHOOTING OF TV SECTION
NO
NO
NO
NO
NO
FLOW CHART NO.2-1 FLOW CHART NO.2-2
Set not operating
YES
YES
YES
YES
YES
Is 120V AC applied to
line between (H) and
(C) of P702 ?
T701 Pin (7) voltage
check about: 170V DC
at 120V AC
B
+
voltage check about:
128.5V (C730
±
side)
Does pulse waveform
exist at line between (2)
and (3) of IC701 ?
Check D701 thru
D704, L701,
R701 and F701.
Is AC cord connected?
Is 170V DC applied to
C705?
Check T701, and
adjacent parts.
Is 16V DC applied to
pin (4) of IC701 ? Check R708 and
IC701.
Check IC701 and
adjacent parts
CRT connector
GC1~GC5 bias check
The Fuse is again
blown out
D701, D702, D703,
D704, D705
Connect AC cord. F701 Check
Normal
Normal IC701, Check
Normal
Abnomal
IC401 (iX2933CE)
Normal
Normal
C854
Blown out
Replace the Fuse
Abnormal
R701
Abnormal
IC701, D727
Normal
R603, Q601,
Q612
AC cord broken.
NO RASTER

25VT-J100 25VT-CJ10
18
FLOW CHART NO.2-4
NO PICTURE, NO SOUND
Check
the
IC401
and
adjacen
t parts.
Check the IC401 and
adjacent parts.
Check the Q431
and adjacent parts.
Check the CRT
connector K1~K5 and
adjacent parts.
IC401 pin (22) bias
check.
IC501 (TA8403) bias
check.
R511, D502, C509,
C510
Vertical freq check
CF631 (503kHz)Normal
Abnormal
IC401
Abnormal
Abnormal
Normal
Normal
NO
FLOW CHART NO.2-3
YES YES
YES
YES
YES YES
YES
NO
NO
NO
NO SoundNO Picture
NO
NO
NO
NO VERTICAL SCAN
Circuit to be checked:
1. TUNER
2. PIF
3. Automatic gain control
4. 9V power source
Check the IC401 and adjacent parts
Check IC2001.
Check the Tuner AGC.
Check
the
IC351.
Does the noise level increase at max,
Contrast, Brightness, and Sound Control ?
Is there a signal at pin
(43) of IC401 ?
noise increases but no
signal is received
Is there a signal at pin
(41) of IC401 ?
Picture noise
decrease but sound
level varies greatly.
Check the tuner bias.
Normal Abnormal
Abnormal
Check the
IC401.
Normal
Check the
Tuner circuit.
Abnormal
Check the
PC9V line.
Normal
Check the
IC401.
Does the 9V (+B)
appear at pin (48)
of the IC401 ?
Is there a signal at
pin (37) of IC401 ? Is there a signal at pin (53) of IC401 ?
Is there
a signal
at pin
(8) & of
IC351
(TDA
7233) ?
Is there
a signal
at pin
(5) of
IC351 ?
Check
the
speaker.
Check
the
IC401,
and
adjacent
parts.
Is there
a signal
at pin
(54) of
IC401 ?

25VT-J100 25VT-CJ10
19
FLOW CHART NO.2-5 FLOW CHART NO.2-7
NO SOUND
FLOW CHART NO.2-6
NO PLAYBACK PICTURE
YES
YES
Is there a signal at pin
(55) of IC401 ?
Check the TV:
TROUBLESHOOTING
"NO SOUND".
NO PLAYBACK SOUND
Check IC401, and
adjacent parts.
Check the VCR:
TROUBLESHOOTI
NG "NO SOUND".
FLOW CHART NO.2-8
Does the infrared remote control
function ?
Is 5V applied at pin (2) of the
remote control receiver ?
Is fluorescent lighting enough away
from the set ?
Is there short-circuit in the key input
or IC2001 ?
Check IC2001
Check the 5V and GND lines.
Check key input terminals.
Replace the infrared remote control
as required.
Check pin (10) of IC2001 and /or
receiver.
Reposition the set not to be
exposed to strong light.
Is "L" pulse given out of pin (1) of
the receiver and received at pin (4)
of IC2001, when the infrared remote
control is activated ?
No operation is possible from the
infrared remote control.
Does waveform appear
at pin (8) of IC351 ?
Check IC351 and
adjacent parts.
Check IC401 and
adjacent parts
Check D725, R327,
C725, C726, FB726
Does approx. 11V appear
at pin (3) of IC351 ?
Check IC401 and
adjacent parts as same
as "NO PICTURE".
Does waveform appear
at pin (54) of IC401 ?
YES
YES
YES
NO
NO
NO
NO
NO
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
Check the VCR:
TROUBLESHOOTI
NG "NO
PLAYBACK".
Is there a signal at pin
(39) of IC401 ?
INFRARED R/C TROUBLESHOOTING

25VT-J100
25VT-CJ10
20
H
G
F
E
D
C
B
A
123456
CHASSIS LAYOUT
PWB-F
SENSOR
UNIT
PWB-E
POWER
SW UNIT
PWB-D
VCR KEY UNIT
PWB-B
CRT UNIT
PWB-C
SUB POWER
UNIT (25VT-CJ100. ONLY)