Sony KV-24FV12, KV-25FV12 Service manual

SERVICE MANUAL

MODEL COMMANDER DEST CHASSIS NO.

B A-5 CHASSIS

KV-24FV12 KV-24FV12 KV-25FV12 KV-25FV12A KV-25FV12C

RM-Y168 US SCC-S40C-A RM-Y168 CND SCC-S41C-A RM-Y168 E SCC-S38G-A RM-Y168 E SCC-S38H-A RM-Y168 E SCC-S38J-A

RM-Y168KV-25FV12A

TRINITRON® COLOR TV

KV-24FV12/25FV12/25FV12A/25FV12C

KV-24FV12

KV-25FV12 KV-25FV12A KV-25FV12C

Power requirements 120V, 60Hz 120-220V, 50/60Hz Number of inputs/outputs

Video

S Video

Audio

Audio Out

Headphone Out

Speaker output(W) 10W x 2 10W x 2

Power Consumption(W)

In use( M a x ) 150W 150W In standby 1W 1W

Dimensions(W/H/D)

(mm)

652 x 524.3 x 467.3mm 652 x 524.3 x 467.3mm

(in)

2/3

x 20

2/3

x 18

5/12

2/3

x 20

2/3

x 18

5/12

Mass

(kg) 37kg 37kg (lbs) 81 lbs 9oz 81 lbs 9oz

SPECIFICATIONS

1) 1 Vp-p 75 ohms unbalanced, sync negative

2) Y: 1 Vp-p 75 ohms unbalanced, sync negative C: 0.286 Vp-p (Burst signal), 75 ohms

3) 500mVrms (100% modulation), impedance: 47kilohms

4) More than 408 mVrms at the maximum volume setting (variable) More than 408 mVrms (fix)

Tele vision system

American TV standard/NTSC P AL M, N (KV-25FV12A ONL Y)

Channel coverage

VHF:2-13/UHF:14-69/CATV:1-125

Visible screen size

24” picture measured diagonally

Actual screen size

25” picture measured diagonally

Antenna

75 ohm external antenna terminal for VHF/UHF

Supplied accessories

Remote Commander RM-Y168 Size AA (R6) batteries (2)

Optional accessories

Connecting cables: VMC-810S/820S, VMC-720M, YC-15V/30V , RK74A U/V mixer EAC-66

Design and specifications are subject to change without notice.

— 2 —

KV-24FV12/25FV12/25FV12A/25FV12C

Section Title Page

Warnings and Cautions...............................................................................................................................................................4

Self-Diagnostic Function .............................................................................................................................................................4

Safety Check-Out Instructions ....................................................................................................................................................7

1. GENERAL........................................................................................................................................................... 8

2. DISASSEMBLY

2-1. Rear Cover Removal.....................................................................................................................................................13

2-2. Chassis Assembly Removal .........................................................................................................................................13

2-3. Service Position ............................................................................................................................................................13

2-4. Picture Tube Removal ...................................................................................................................................................14

3. SET-UP ADJUSTMENTS

3-1. Beam Landing...............................................................................................................................................................15

3-2. Convergence.................................................................................................................................................................16

3-3. Focus.............................................................................................................................................................................17

3-4. Screen (G2) ................................................................................................................................................................... 17

3-5. Method of Setting the Service Adjustment Mode .........................................................................................................18

3-6. White Balance Adjustments..........................................................................................................................................18

4. SAFETY RELATED ADJUSTMENTS

4-1. R564 Confirmation Method (HV Hold-Down Confirmation and Readjustments) .................................................... 1 9

4-2. B+ Voltage Confirmation and Adjustment .....................................................................................................................19

5. CIRCUIT ADJUSTMENTS

5-1. Setting the Service Adjustment Mode ..........................................................................................................................21

5-2. Memory Write Confirmation Method .............................................................................................................................21

5-3. Adjustment Buttons and Indicators...............................................................................................................................21

5-4. A Board Adjustments ....................................................................................................................................................23

6. DIAGRAMS

6-1. Block Diagram...............................................................................................................................................................27

6-2. Circuit Board Location ..................................................................................................................................................31

6-3. Printed Wiring Boards and Schematic Diagrams .........................................................................................................31

• A Board .................................................................................................................................................................... 33

• MB Board .................................................................................................................................................................39

• CB Board..................................................................................................................................................................45

• HZ Board ..................................................................................................................................................................46

• K Board .................................................................................................................................................................... 47

• VB Board ..................................................................................................................................................................48

6-4. Semiconductors ............................................................................................................................................................49

7. EXPLODED VIEW

7-1. Chassis (KV-24FV12 ONLY) ........................................................................................................................................50

7-2. Chassis (KV-25FV12A ONLY) .......................................................................................................................................51

7-3. Chassis (KV-25FV12/25FV12C ONLY)........................................................................................................................52

8. ELECTRICAL P AR TS LIST.................................................................................................................................................53

— 3 —

KV-24FV12/25FV12/25FV12A/25FV12C

WARNINGS AND CAUTIONS

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

ON THE SCHEMA TIC DIAGRAMS, EXPLODED VIEWS, AND IN THE PARTS LIST ARE CRITICAL FOR 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 FOR SAFE OPERA TION ARE IDENTIFIED IN THIS MANUAL. FOLLOW THESE PROCEDURES WHENEVER CRITICAL COMPONENTS ARE REPLACED OR IMPROPER OPERATION IS SUSPECTED.

ATTENTION!!

APRES AVOIR DECONNECTE LE CAP DE L'ANODE, COURT-CIRCUITER L'ANODE DU TUBE CATHODIQUE ET CELUI DE L'ANODE DU CAP AU CHASSIS METALLIQUE DE L'APPAREIL, OU AU COUCHE DE CARBONE PEINTE SUR LE TUBE CATHODIQUE OU AU BLINDAGE DU TUBE CATHODIQUE.

ATTENTION!!

AFIN D'EVITER TOUT RESQUE D'ELECTROCUTION PROVENANT D'UN CHÁSSIS SOUS TENSION, UN TRANSFORMATEUR D'ISOLEMENT DOIT ETRE UTILISÉ LORS DE TOUT DÉPANNAGE. LE CHÁSSIS DE CE RÉCEPTEUR EST DIRECTEMENT RACCORDÉ À L'ALIMENTATION SECTEUR.

A TTENTION AUX COMPOSANTS RELATIFS A LA SECURITE!!

LES COMPOSANTS IDENTIFIES PAR UNE TRAME ET PAR UNE MARQUE

SUR LES SCHEMAS DE PRINCIPE, LES VUES EXPLOSEES ET LES

LISTES DE PIECES SONT D'UNEIMPORTANCE CRITIQUE POUR LA SECURITE DU FONCTIONNEMENT. NE LES REMPLACER QUE PAR DES COMPOSANTS SONY DONT LE NUMERO DE PIECE EST INDIQUE DANS LE PRESENT MANUEL OU DANS DES SUPPLEMENTS PUBLIES P AR SONY. LES REGLAGES DE CIRCUIT DONT L'IMPORTANCE EST CRITIQUE POUR LA SECURITE DU FONCTIONNEMENT SONT IDENTIFIES DANS LE PRESENT MANUEL. SUIVRE CES PROCEDURES LORS DE CHAQUE REMPLACEMENT DE COMPOSANTS CRITIQUES, OU LORSQU'UN MAUV AIS FONTIONNEMENT SUSPECTE.

SELF-DIAGNOSTIC FUNCTION

The units in this manual contain a self-diagnostic function. If an error occurs, the ST ANDBY/TIMER LED will automatically begin to flash. The number of times the LED flashes translates to a probable source of the problem. A definition of the STANDBY/TIMER LED flash indicators is listed in the instruction manual for the user’s knowledge and reference. If an error symptom cannot be reproduced, the Remote Commander can be used to review the failure occurrence data stored in memory to reveal past problems and how often these problems occur.

Diagnostic Test Indicators

When an error occurs, the STANDBY/TIMER LED will flash a set number of times to indicate the possible cause of the problem. If there is more than one error, the LED will identify the first of the problem areas.

Results for all of the following diagnostic items are displayed on screen. No error has occurred if the screen displays a “0”.

— 4 —

Display of Standby/Timer LED Flash Count

2 times 4 times 5 times

KV-24FV12/25FV12/25FV12A/25FV12C

LED ON 0.3 sec. LED OFF 0.3 sec.

Diagnostic Item Flash Count*

+B overcurrent 2 times V ertical deflection stopped 4 times White balance failure 5 times

*One flash count is not used for self-diagnostic.

LED OFF

3 sec.

STANDBY/TIMER LED

Stopping the Standby/Timer LED Flash

Turn off the power switch on the TV main unit or unplug the power cord from the outlet to stop the STANDBY/TIMER LAMP from flashing.

Self-Diagnostic Screen Display

For errors with symptoms such as “power sometimes shuts off” or “screen sometimes goes out” that cannot be confirmed, it is possible to bring up past occurrences of failure on the screen for confirmation.

To Bring Up Screen Test

In standby mode, press buttons on the Remote Commander sequentially, in rapid succession, as shown below:

Display Channel

Sound volume

Power ON

Self-Diagnostic Screen Display

SELF DIAGNOSTIC

2: 0 3: N/A 0 4: 0 5: 1 101: N/A 0

Note that this differs from entering the service mode (sound volume

Numeral “0” means that no fault was detected.

Numeral “1” means a fault was detected one time only.

— 5 —

KV-24FV12/25FV12/25FV12A/25FV12C

Handling of Self-Diagnostic Screen Display

Since the diagnostic results displayed on the screen are not automatically cleared, always check the self-diagnostic screen during repairs. When you have completed the repairs, clear the result display to “0”.

Unless the result display is cleared to “0”, the self-diagnostic function will not be able to detect subsequent faults after completion of the repairs.

Clearing the Result Display

To clear the result display to “0”, press buttons on the Remote Commander sequentially when the diagnostic screen is displayed, as shown below:

Quitting the Self-Diagnostic Screen

To quit the entire self-diagnostic screen, turn of f the power switch on the Remote Commander or the main unit.

ENTERChannel

Self-Diagnostic Circuit

+B overcurrent (OCP) Occurs when an overcurrent on the +B (135V) line is detected by pin 18 of IC1301 (MB Board).

If the voltage of pin 18 of IC1301 (MB Board) is less than 1V when V.SYNC is more than seven verticals in a period, the unit will automatically turn off.

I-Prot Occurs when an absence of the vertical deflection pulse is detected by pin 17 of IC1001 (MB

Board). Power supply will shut down when waveform interval exceeds 2 seconds.

IK If the RGB levels* do not balance within 2 seconds after the power is turned on, this error will be

detected by IC1301 (MB Board). TV will stay on, but there will be no picture.

*(Refers to the RGB levels of the AKB detection Ref pulse that detects 1K).

— 6 —

SAFETY CHECK-OUT

KV-24FV12/25FV12/25FV12A/25FV12C

After correcting the original service problem, perform the following saf ety 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 touching 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, particularly 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 replacement.

6. Check the line cords for cracks and abrasion. Recommend the replacement of any such line cord to the customer.

7. Check the B+ and HV to see if they are specified values. Make sure your instruments are accurate; be suspicious of your HV meter if sets always have low HV.

8. Check the antenna terminals, metal trim, “metallized” knobs, screws, and all other exposed metal parts for AC leakage. Check leakage as described below.

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

0.5 mA (500 microamperes). Leakage current can be measured by any one of three methods.

1. A commercial leakage tester, such as the Simpson 229 or RCA WT-540A. Follow the manufacturers' instructions to use these instructions.

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 voltmeter. The “limit” indication is 0.75 V, so analog meters must have an accurate low voltage scale. The Simpson’s 250 and Sanwa SH-63TRD are examples of passive VOMs that are suitable . Nearly all battery-operated digital multimeters that have a 2 VAC range are suitable (see Figure A).

How to Find a Good Earth Ground

A cold-water pipe is a guaranteed earth ground; the coverplate retaining screw on most AC outlet bo x es 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 z ero ohms . If a cold-water pipe is not accessible, connect a 60- to 100-watt troub lelight (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 on the line; the lamp should light at normal brilliance if the screw is at ground potential (see Figure B).

— 7 —

Trouble Light

AC Outlet Box

Figure B. Checking for earth ground.Figure A. Using an AC voltmeter to check AC leakage.

Ohmmeter

Cold-water Pipe

The instructions mentioned here are partial abstracts from the Operating Instruction Manual.

Connecting Additional Equipment

TV and VCR

Connect the coaxial cable from your TV antenna or cable service to the IN jack on your VCR.

Connect a coaxial cable (not supplied) from the OUT jack on your VCR to the VHF/UHF jack on the TV.

(Optional connection)

If your VCR is equipped with video outputs, you can get better picture quality by connecting A/V cables (not supplied) from AUDIO and VIDEO OUT on your VCR to AUDIO/VIDEO IN on your TV.



To watch video programs from your VCR, tune your TV to channel 3 or 4 (as set on the rear of your VCR).



You can use the button to switch between the VHF/UHF and VIDEO inputs.



For optimum picture quality, use S VIDEO (if your VCR is equipped with t he S VIDEO connection) instead of the yellow A/V cable. S VIDEO does not provide sound, the audio cables must still be connected.

(Optional connection)

From

VCR

Rear of TV

cable/

Coxial Cable

antenna

The page numbers shown reflect those of the Operating Instruction Manual.

Connecting Your TV

Read this section before setting up your TV for the first time. This section covers basic connections in addition to any optional equipment you may be connecting.

Basic Connections

TV with indoor or outdoor antenna, or CATV cable

Depending on the cable available in your home, choose one of the connections below:

KV-24FV12/25FV12/25FV12A/25FV12C

SECTION 1 GENERAL

— 8 —



If you are connecting to an indoor or outdoor antenna, you may need to adjust the orientation of the antenna for best reception.

TV and Cable Box

TV, VCR and Cable box

Connect the coaxial cable from your cable service to the IN jack on your cable box.

Connect a coaxial cable (not supplied) from the OUT jack on your cable box to the IN jack on your VCR.

Connect a coaxial cable (not supplied) from the OUT jack on your VCR to the VHF/UHF jack on the TV.

(Optional connection)

If your VCR is equipped with video outputs, you can get better picture quality by connecting A/V cables (not supplied) from AUDIOand VIDEO OU Ton your VCRto AU DIO/VIDEOIN on your TV.



If you will be controlling all channel selection through your cable box, you should consider using the Channel Fix feature, (see page 21).



You can use the button to switch between the VHF/UHF and VIDEO inputs.



For optimum picture quality, use S VIDEO (if your VC R is equipped with the S VIDEO connection) instead of the yellow A/V cable. S VIDEO does not provide sound, the audio cables must still be connected.

From cable

(Optional connection)

Cable box

VCR

Rear of TV

Coaxial Cable

Coaxial

— 9 —

1 2



Cable

From cable

Connect the coaxial cable from your cable service to the IN jack on your cable box.

Connect a coaxial cable (not supplied) from the OUT jack on your cable box to the VHF/UHF jack on the TV.

To view channels from your cable box, tune your TV to channel 3 or 4 (as set on the rear panel of y our cab le box) a nd use the cabl e box ’s remote control to change channels.

Cable Box

Coaxial Cable

Rear of TV

KV-24FV12/25FV12/25FV12A/25FV12C



If you will be controlling all channel selection through your cable box, you should consider using the Channel Fix feature, (see page 21).

TV and Satellite Receiver

TV, Satellite Receiver and VCR

1 Connect the cable from your satellite antenna to SATELLITE IN on

the satellite receiver.

2 Connect the coaxial cable from your cable service or antenna to the

IN jack on your VCR.

3 Using a coaxial cable, connect the OUT jack on your VCR IN to the

VHF/UHFjackonyourTV.

4 Using A/V cables, connect AUDIO and VIDEO OUT on your

satellite receiver to AUDIO and VIDEO IN on your VCR.

5 Using A/V cables,connect AUDIO and VIDEO OUT on yourVCR to

AUDIO and VIDEO IN on your TV.



To view from the satellite receiver or VCR, select the video input to which your satellite receiver or VCR is connected by pressing on the remote control.

AUDIO R AUDIO L VIDEO

SATELLITE IN

VHF/UHF

OUT

LINE OUT

LINE IN

VHF/UHF

OUT

LINE OUT

Satellite receiver

Rear of TV

VCR

Satellite antenna

From antenna

cable/

cable

Rear of TV

From

cable/ antenna

Satellite receiver

— 10 —

Satellite antenna cable

Connect the cable from your satellite antenna to SATELLITE IN on

SATELLITE IN

AUDIO R AUDIO L VIDEO

LINE OUT

VHF/UHF

OUT

your satellite receiver.

Connect the coaxial cable from your cable service or antenna to the VHF/UHF jack on your TV.

Using A/V cables, connect AUDIO and VIDEO OUT on your satellite receiver to AUDIO and VIDEO IN on your TV.



You can use the button to switch between the VHF/UHF and VIDEO inputs.



For optimum picture quality, use S VIDEO (if your Satellite Receiver is equipped with the S VIDEO connection) instead of the yellow A/V cable. S VIDEO does not provide sound, the audio cables must still be connected.

KV-24FV12/25FV12/25FV12A/25FV12C

Using the Remote Control and

MTS/SAP Cycles through the Multi-channel

TV Sound (MTS) options: Stereo, Mono, and Auto-SAP (Second Audio Programming).

DISPLAY Press to display the current time,

(if set) and channel number . Cycles through available Steady

Sound settings, (see page 19).

JUMP Alternates between the lasttwo

channels selected with the buttons.

GUIDE Brings up the custom guide of

your satellite receiver.

MENU Displays the on-screenmenu.

Press again to exit the menu at any time.

RESET Press to returnto factory settings

while in an on-screen menu.

CODE SET Use to program your remote

control to operate connected videoequipment,(seepage31).



If you lost your remote control, see page 35.

0 9

Basic Functions

This section shows you how to use the more advanced buttons on the remote control and how to use the on-screen menus.

Using the Remote Control

— 11 —

Button Description POWER Press when you want to turn

FUNCTION Press when you want to control

MUTING Instantly turns off the sound.

SYSTEM OFF Powers off all Sony equipment at

TV/VIDEO Cycles through availablevideo

TV/VTR Press when you are finished

PICTURE MODE Cycles through the available

SLEEP Turns the TV off automatically in

connected equipment on and off.

connected equipment with your remote control.

Press again or press to restore sound.

once, (may not work with older equipment).

inputs.

using a VCR and you want to switch to the TV input. Your VCR power will remain on.

Moves the cursor in theon-screen menus. Press the arrow buttons to move the cursor, press the center button to select or access an option.

VideoMode settings.

approximately15, 30, 45, 60, or 90 minutes. Cancel by pressing until SLEEP OFF appears.

KV-24FV12/25FV12/25FV12A/25FV12C

(continued)

— 12 —

Troubleshooting

If you are having a problem with your TV , try the suggestions below. If the problem persists, contact your nearestSony dealer.

No picture, no sound

Poor or no picture, good sound

Good picture, no sound

No color Only snow

appears on the screen

Dotted linesor stripes

Double images or ghosts



Make sure the power cord is plugged in.



If a red light is flashing on the front of your TV for more than a few minutes, disconnect and reconnect the power cordto restore the TV. If the problem continues,call your local service center.



Check the TV/VIDEO settings: when watching TV,set to TV; when watching video equipment, set to VIDEO (page 11).



Make sure the batteries havebeen inserted correctly into the remote control (page 2).



Try another channel, it could be station trouble.



Adjust Picture in the Video menu (page 18).



Adjust Brightness in the Video menu (page 18).



Check the antenna and/or cable connections(page 3).



Press sothatMUTINGdisappearsfromthe screen (page 11).



Check your Audio settings. Your TV may be set to Auto-SAP (page 20).



Adjust Color in the Video menu (page 18).



Check the Cable setting in the Options menu under Setup (page 30).



Check the antenna and/or cable connections(page 3).



Make sure the channel selected is currently broadcasting.



Adjust the antenna.



Move the TV away from other electronic equipment. Some electronic equipment can create electrical noise, which can interferewith TV reception.



Check your outdoorantenna or callyour cable service.

KV-24FV12/25FV12/25FV12A/25FV12C

2-1. REAR COVER REMOVAL

KV-24FV12/25FV12/25FV12A/25FV12C

SECTION 2

DISASSEMBLY

Screw +BVTP 4x16

Rear Cover

2 Screws +BVTP 4x12

Screw +BVTP 4x16

2-2. CHASSIS ASSEMBLY REMOVAL 2-3. SERVICE POSITION

CB Board

VB Board

Claw

MB Board

K Board

A Board

— 13 —

MB Board

K Board

A Board

(KV-25FV12A ONLY)

HZ Board

KV-24FV12/25FV12/25FV12A/25FV12C

2-4. PICTURE TUBE REMOVAL

WARNING:

BEFORE REMOVING

THE ANODE CAP

High voltage remains in the CRT even after the power is disconnected. T o avoid electric shock, discharge CRT before attempting to remove the anode cap. Short between anode and CRT coated earth ground strap.

Coated

Earth

Ground

Strap

7 6

1. Discharge the anode of the CRT and remove the anode cap.

2. Unplug all interconnecting leads from the deflection yoke, neck assembly, degaussing coils and CR T grounding strap.

3. Remove the CB Board from the CRT.

4. Remove the chassis assembly.

5. Loosen the neck assembly fixing screw and remove.

6. Loosen the deflection yoke fixing screw and remove.

7. Place the set with the CRT face down on a cushion and remove the degaussing coil holders.

8. Remove the degaussing coils.

9. Remove the CRT grounding strap and spring tentioners.

10. Unscrew the four CRT fixing screws [located on each CRT corner] and remove the CRT [Take care not to handle the CRT by the neck].

ANODE CAP REMOVAL

WARNING: High voltage remains in the CRT even after the power is disconnected. To avoid electrical shock, discharge the CRT before

NOTE: After removing the anode, short circuit the anode of the picture tube and the anode cap to either the metal chassis, CRT shield,

attempting to remove the anode cap. Short between anode and coated earth ground strap of CRT.

or carbon painted on the CRT.

REMOVAL PROCEDURES

Anode Button

Turn up one side of the rubber cap in the direction indicated by arrow

Use your thumb to pull the rubber cap firmly in the direction indicated by arrow

When one side of the rubber cap separates from the anode button, the anode cap can be removed by turning the rubber cap and pulling it in the direction of arrow

HOW TO HANDLE AN ANODE CAP

Do not use sharp objects which may cause damage to the surface of the anode cap.

To avoid damaging the anode cap, do not squeeze the rubber covering too hard. A material fitting called a shatter-hook terminal is built into the rubber.

Do not force turn the foot of the rubber cover. This may cause the shatter-hook terminal to protrude and damage the rubber.

— 14 —

SECTION 3

SET-UP ADJUSTMENTS

KV-24FV12/25FV12/25FV12A/25FV12C

The following adjustments should be made when a complete realignment is required or when a new picture tube is installed.

These adjustments should be performed with rated power supply voltage unless otherwise noted.

Set the controls as follows unless otherwise noted: VIDEO MODE: STANDARD

PICTURE control: ................ Normal

BRIGHTNESS control: ........ Normal

3-1. BEAM LANDING

Before beginning adjustment procedure:

1. Degauss the entire screen.

2. Feed in the white pattern signal.

Adjustment Procedure

1. Input a raster signal with the pattern generator .

2. Loosen the deflection yoke mounting screw and set the purity control to the center as shown below.

Perform the adjustments in order as follows:

1. Beam Landing

2. Convergence

3. Focus

4. Screen (G2)

5. White Balance

Note: T est equipment required:

• Color Bar Pattern Generator

• Degausser

• DC Power Supply

• Digital Multimeter

5. Move the deflection yoke forward and adjust so that the entire screen becomes green.

Purity Control

3. T urn the raster signal of the pattern generator to green.

4. Move the deflection yoke backward and adjust the purity control so that green is in the center and red and blue are at the sides evenly.

Blue Red

Green

6. Switch over the raster signal to red and blue and confirm the condition.

7. When the position of the deflection yoke is determined, tighten it with the deflection yoke mounting screw .

8. If landing at the corner is not right, adjust by using the disk magnets.

Purity control

corrects this area

Disk magnets or rotatable disk magnets correct

these areas (a-d)

Deflection yoke positioning

corrects these areas

— 15 —

KV-24FV12/25FV12/25FV12A/25FV12C

3-2. CONVERGENCE

Before starting convergence adjustments:

1. Perform FOCUS, V.LIN AND V.SIZE adjustments.

2. Set BRIGHTNESS control to minimum.

3. Feed in dot pattern.

Vertical Static Con vergence

1. Adjust V.STAT magnet to converge red, green and blue dots in the center of the screen (Vertical movement adjust V.STAT RV701 to converge).

Horizontal Static Convergence

If the blue dot does not converge with the red and green dots, perform the following:

1. Move BMC magnet (a) to correct insufficient H. Static convergence.

2. Rotate BMC magnet (b) to correct insufficient V. Static convergence.

3. After adjusting the BMC magnet, repeat Beam Landing Adjustment.

V-STAT

BMC MAGNET

PURITY

2. Tilt the V.STAT magnet and adjust static convergence to open or close the V.STAT magnet.

When the V.STAT magnet is moved in the direction of arrows a and b, red, green, and blue dots move as shown below:

(1)

(2) a

(3)

G R

BGR

RGB

B G

BMC magnet

Dynamic Convergence Adjustment

Before performing this adjustment, perform Horizontal and Vertical Static Convergence Adjustment.

1. Slightly loosen deflection yoke screw.

2. Remove deflection yoke spacers.

3. Move the deflection yoke for best convergence as shown on the following page.

— 16 —

KV-24FV12/25FV12/25FV12A/25FV12C

a-d: screen-corner

misconvergence

BGR

RGB

R G B

BGR

B G R

RGB

BGR RGB

R G B

4. Tighten the deflection yoke screw.

5. Install the deflection yoke spacers.

TLH Plate Adjustment

1. Input crosshatch pattern.

2. Adjust PICTURE QUALITY to standard, PICTURE and BRIGHTNESS to 50%, and OTHER to standard.

3. Adjust the Horizontal Convergence of red and blue dots by tilting the TLH plate on the deflection yoke.

Perform adjustments while tracking items 1 and 2.

Screen-Corner Convergence

1. A ffix a permalloy assembly corresponding to the misconverged areas.

3-3. FOCUS

1. Adjust FOCUS control for best picture.

Focus (FV)

Screen (G2)

3-4. SCREEN (G2)

1. Input a dots pattern.

2. Set the PICTURE and BRIGHTNESS controls at minimum and COLOR control at normal.

3. Adjust SBRT, GCUT, BCUT in service mode with an oscilloscope as shown below so that voltages on the red, green, and blue cathodes are 170 VDC.

4. Adjust XCV core to balance X axis.

5. Adjust YCH VR to balance Y axis.

6. Adjust vertical red and blue convergence with V.TILT (TLV VR).

B R R B (R)(B) (B)(R)

TLH+ TLH-

Pedestal

Ground

170 VDC

4. Observe the screen and adjust SCREEN (G2) VR in FBT to obtain the faintly visible background of dot signal.

— 17 —

+ 37 hidden pages

Sony KV-24FV12, KV-25FV12 Service manual

SPECIFICATIONS

TABLE OF CONTENTS

DISASSEMBLY

SET-UP ADJUSTMENTS