Panasonic CT-20SX11E, NA6DV Schematic

ORDER NO. MTNC010735C1 B1

Service Manual

Color Television

Main Manual

(NA6DV)

Panasonic

Models

Chassis

CT-20SX11E AP380 CT-20SX11CE AP380

This Service man ual is issued as a service guide for the models o f the NA6DV fam ily listed abov e. Included in th is manual are a set of schematics, block diagrams, functional descriptions, alignment procedures, disassembly procedures, and a complete parts list.

“WARNING! This Service Man ual is desig ned for expe rienced repa ir technici ans only and is not designed f or use by t he general p ublic. It does not contain warnings or cautions to advise non-technical individuals of potential dangers in attempting to service a product. Products powered by electricity should be serviced or repaired only by experien ced profess ional techn icians. Any attempt to service or repair the product or products dealt with in this Service Manual by anyone else could result in serious injury or death.”

The service technician is required to read and follow the “Safety Precautions” and “Important Safety Notice” in this Main Manual.

Important Safety Notice

Special components are used in this television set which are important for safety. These parts are identified on the schematic diag ram by the s ymbol and printed in BOLD TYPE o n the replac ement part l ist. It is es senti al that

these critical parts are replaced with the manufacturer ’s specified replacement part to prevent X-ray radiation, shock, fire or other hazards. Do not modify the original design without the manufacturer’s permission.

Safety Precautions

General Guidelines

An Isolation Transformer should always be used during the servicing of a r eceiver whose c hassis is not isolated from AC power line. Use a transformer of adequate power rating as this protects the technician from accidents resulting in personal injury from electrical shocks. It will also protec t the Receiver from being damaged by accidenta l shorting that may occur during servicing. When servicing, observe the original lead dress, especially in the high voltage circuit. Replace all damaged parts (also parts that show signs of overheating.) Always Replace Protective Devices, such as fishpaper, isolation resistors and capacitors, and shields after servicing the Receiver. Use only manufacturer ’s recommended rating for fuses, c ircuits breakers, etc. High potentials are present when this Receiver is operating. Operation of the Receiver without the rear cover introduces danger for elect rical shock. S ervicing should not be performed by anyone who is not thoroughly familiar with the necessary precautions when servicing high-voltage equipment.

Extreme care should be practiced when Handling the Picture T ube. Rough handling may cause it to implode

due to atmospheric pres sure. (14.7 lbs per sq. in.). D o not nick or scratch the glass or subject it to any undu e pressure. When handling, use safety goggles and heavy gloves for protection. Discharge the picture tube by shorting the anode to chassis ground (not to the cabinet or to other mounting hardware). When discharging con nec t co ld ground (i.e. da g gr oun d lea d) to the anode with a well insulated wire or use a grounding probe. Avoid prolonged exposure at close range to unshielded areas of the picture tube to prevent exposure to Xray radiation. The Test Picture Tube used for servicin g the chassis at the bench should incorporate safety glass and magnetic shieldi ng. The safety glass pro vide shielding for the tube viewing area against X-ray radiation as well as implosion. The magnetic sh ield limits the X-ray radiation around the bell of the pict ure tube in addition to the restricting magnetic effects. When using a picture tube test jig for service, ensure that the jig is capable of handling 40kV without causing Xray radiation. Before returning a serviced rec eiver to the owner, the service technic ian must thoroughly test the unit to ensure that is completely safe to operate. Do not use a

line isolation transformer when testing.

Leakage Current Cold Check

Unplug the AC cord and connect a jumper between the two plug prongs. Measure the resistance between the jumpered AC plug and expose metallic parts such as screwheads, antenna terminals, control shafts, etc. If the exposed metallic part has a return path to the chassis, the reading should be between 240kΩ and 5.2MΩ. If the exposed metallic part does not have a return path to the chassis, the reading should be infinite.

Leakage Current Hot Check (Fig. 1)

Plug the AC cord directly into the AC outlet. Do not use an isolation transformer during the check. Connect a 1.5kΩ 10 watt resistor in parallel with a

0.15µF capacitor between an exposed metallic part and ground. Use earth ground, for example a water pipe. Using a DVM with a 1000 ohms/volt sensitivity or higher, measure the AC potential across the resistor. Repeat the procedure and measure the voltage present with all other exposed metallic parts. Verify that any potential does not exceed 0.75 volt RMS. A leakage curr ent tes ter (suc h a S impson M odel 229, Sencore Model P R57 or equiv alent) may be used in the above procedure, in which case any current measure must not exceed 1/2 milliamp. If any measurement is out of the specified limits, there is a possibility of a s hock haz ar d and th e R ece iv er m us t b e repaired and rechecked before it is returned to the customer.

AC VOLTMETER

COLD WATER PIPE (GROUND)

0.15µF

TO INSTRUMENT’S EXPOSED METAL PARTS

1500Ω,10 W

Figure 1. Hot Check Circuit

X-ray Radiation

WARNING: The potential source of X-ray radiation in the

TV set is in the H igh Voltage section and th e p ict ure tu be.

Note: It is important to use an accurate, calibrated

high voltage meter.

Set the brightness, picture, sharpness and color controls to Minimum. Measure the High Voltage. The high voltage should be 27.7kV ± 1.25kV. If the upper

limit is out of tolerance, immediate service and correction is required to insure safe operation and to prevent the possibility of premature component failure.

- 2 -

Important Safety Notice . . . . . . . . . . . . . . . . . . 2

Safety Precautions. . . . . . . . . . . . . . . . . 2

Service Notes. . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Receivers Feature Table. . . . . . . . . . . . . . . . . . 6

Location of Controls (Receiver)

Receiver Front Control Panel. . . . . . . . . 7

Location of Controls (Remote)

EUR511502 . . . . . . . . . . . . . . . . . . . . . . 8

Disassembly for Service. . . . . . . . . . . . . . . . . . 9

Disassembly for CRT Replacement. . . . . . . . . 9

Chassis Service Adjustment Procedures. . . 10

Service Adjustments

(Electronic Control). . . . . . . . . . . . . . . . . . 21

Sub-Brightness. . . . . . . . . . . . . . . . . . . 21

Video Adjustment Level . . . . . . . . . . . . 21

Sub-Contrast. . . . . . . . . . . . . . . . . . . . . 21

Tint/Color Adjustment. . . . . . . . . . . . . . 21

Color Temperature Adjustment. . . . . . . 22

Complete Adjustment. . . . . . . . . . . . . . 22

Horizontal Centering. . . . . . . . . . . . . . . 23

Audio Adjustment . . . . . . . . . . . . . . . . . 23

MTS Circuit Adjustment . . . . . . . . . . . . 23

Input Level Adjustment. . . . . . . . . . . . . 23

Stereo Separation Adjustment (Sb) . . . 23

Clock Adjustment (Sb) . . . . . . . . . . . . . 24

Vertical Size . . . . . . . . . . . . . . . . . . . . . 24

Service Adjustments

(Mechanical Controls). . . . . . . . . . . . . . . . 24

VCO Field Adjustment L105. . . . . . . . . 24

Focus (Part of T551). . . . . . . . . . . . . . . 24

E-W Pincushion . . . . . . . . . . . . . . . . . . 24

H-Width. . . . . . . . . . . . . . . . . . . . . . . . . 24

132V B+ Voltage Confirmation. . . . . . . 10

Source Voltage Chart. . . . . . . . . . . . . . 10

High Voltage Check . . . . . . . . . . . . . . . 10

Purity and Convergence Procedures . . . . . . .11

Service Mode (Electronic Controls). . . . . . . . 14

Entering Service Mode. . . . . . . . . . . . . 14

Toggle between Modes. . . . . . . . . . . . . 14

Exiting the Service Mode . . . . . . . . . . . 14

Sub-Data Adjustment. . . . . . . . . . . . . . 15

Cut-Off Adjustment. . . . . . . . . . . . . . . . 15

Options Adjustment . . . . . . . . . . . . . . . 16

MTS Adjustment. . . . . . . . . . . . . . . . . . 16

Comb Filter Adjustment . . . . . . . . . . . . 17

To Check Purity . . . . . . . . . . . . . . . . . . 18

Helpful Hints. . . . . . . . . . . . . . . . . . . . . 18

Instructional Flow Chart

for Service Mode. . . . . . . . . . . . . . . . . . . . 19

Audio Signal Path Block Diagram . . . . . . . . . 25

Video-Chroma Signal Path

Block Diagrams. . . . . . . . . . . . . . . . . . . . . 26

Component Identification. . . . . . . . . . . . . . . . 27

Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

C-Board

Schematic, Layout & Voltages . . . . . . . . . . 38

A-Board Schematic

Left Section . . . . . . . . . . . . . . . . . . . . . . . . 39

Right Section. . . . . . . . . . . . . . . . . . . . . . . 40

A-Board Layout. . . . . . . . . . . . . . . . . . . . . . . 41

A-Board Voltages . . . . . . . . . . . . . . . . . . . . . 42

Z-Board

Schematic, Layout & Voltages. . . . . . . . . . 43

Waveforms

A-Board. . . . . . . . . . . . . . . . . . . . . . . . . . 44

- 3 -

Service Notes

Chip Components

TRANSISTOR

CAPACITOR

RESISTOR

MH DIODE

SOLDER CAPS

1ST DIGIT

2ND DIGIT

MULTIPLIER =1600 = 1.6k

GRADE

TYPE

COMMON

ANODES

CATHODE

Note: These components are affixed with glue. Be careful not to break or damage any foil under the

component or at the pins of the ICs when removing. Usually applying heat to the component for a short time while twisting with tweezers will break the component loose.

Leadless Chip Component (surface mount)

Chip components must be replaced with identical chips due to critical foil tr ack spacing. There are no ho les in the board to mount standard transistors or diodes. Some chips capacitor or resistor board solder pads may have holes thr ough the board, however the hole diameter limits standard resistor replacement to 1/8 watt. Standard capacitor may also be limited for the same reason. It is recommended that identical components be used. Chip resistor have a three digit numerical resistance code - 1st and 2nd significant digits and a multiplier. Example: 162 = 1600 or 1.6kΩ resistor, 0 = 0Ω (jumper). Chip capacitors generally do not have the value indicated on the capacitor. The color of the compo nent indicates the general range of th e capacitance. Chip transistors are id enti fied by a two letter c ode . Th e first letter indicates the type and the second l etter, the grade of transistor. Chip diodes have a two lette r i den tif ic ati on code as per the code chart an d are a dual diode pack with either common anode or common cathode. Check the parts list for correct diode number.

Component Removal

1. Use solder wick to remove s older fr om compo nent end caps or terminal.

2. Without pulling up, carefully twist the component with tweezers to break the adhesive.

3. Do not reuse removed leadless or chip components since they are subject to stress fracture during removal.

Chip Component Installation

1. Put a small amount of solder on the board soldering pads.

2. Hold the chip component against the soldering pads with tweezers or with a miniature alligator clip and apply heat to the pad area with a 30 watt iron until solder flows. Do not appl y heat for more than 3 seconds.

How to Replace Flat-IC

- Required Tools -

• Soldering iron • De-solder braids

• Needle nose pliers • Magnifier

• Wire cutters (sharp & small)

1. Cut the pins of a defective IC with wire cutters. Remove IC from boar d. If IC i s glued to the boa rd, heat the IC and release the IC. See Note above.

Flat IC

2. Using soldering iron and needle nose pliers remove the IC pins from the board.

Soldering Iron

3. Using de-soldering braid and soldering iron remove solder from affected are on board (pads).

De-soldering Braid

Soldering Iron

4. Position the new Flat-IC in pl ace (apply the pins of the Flat-IC to the soldering pads where the pins need to be soldered). Determine the positions of the soldering pads and pins by correctly aligning the polarity symbol. Solder pin #1 first, align the IC.

Polarity symbol

2nd solder

1st solder

Solder the pin op posite to pin #1. This will assist positioning the IC.

5. Solder all pins to the soldering pads using a fine tipped soldering iron.

Solder

Soldering Iron

6. Check with a magnifier fo r solder bridge between the pins or for d r y jo int b etwe en pi ns a nd so ld erin g pads. To rem ove a solder bridge, use a de-solder braid as shown in the figure below.

- 4 -

Service Notes (Continued)

IMPORTANT: To protect against possible damage to

the solid state devices due to arcing or static discharge, make cer tain that all g round wir es and CTR DAG wire are securely connected.

WARNING: This Receiver has been designed to mee t or exceed applicable safety and X-ray radiation protection as specified by government agencies and independent testing laboratories.

CAUTION: The power supply circuit is above earth ground and the chassis cannot be polarized. Use an isolation transformer when servicing the Receiver to avoid damage to the test equipmen t or to the chassis. Connect the test equipment to the proper ground ( ) or

( ) when servicing, or incorrect voltages will be measured.

To maintain original product safety design standards relative to X-ray radiation and shock and fire hazard,

parts indicated with the symbol on the schematic must be replaced with identi cal parts. Order parts from

the manufacturer’s parts center using the parts numbers shown in t his service manual, o r provide the chassis number and the part reference number.

For optimum performanc e and rel iability, all other parts should be replaced with components of identical specification.

- 5 -

Receiver Feature Table

FEATURE\MODEL

Chassis AP380 Tuning system 40K # of channels 181 Menu language Eng/Span/Fr Closed Caption X V-Chip X 75 Ω input X Remote Model # EUR511502 Picture tube A51LSK955X-A PureFlat Picture Tube X Comb Filter 3 Line Digital H. Edge Correction X V/A norm Both MTS/SAP/DBX X Bass/Treble/Balance X Surround Sound X AI Sound X

CT-20SX11E &

CT-20SX11CE

FAO & VAO X Built-in audio power 5Wx2 (10%) # of speakers 2 A/V in (rear/front) 2(2/1) S-VHS Input (rear/front) 1/0 Headphone Jack X Dimensions mm

(WxDxH) in Weight (kg/lbs) 24.5/54.13 Power source (V/Hz) 120/60 Anode voltage 27.7kV ± 1.25kV Video input jack Audio input jack 500mV RMS 47kΩ A-Board TNP2AH019 KA C-Board TNP2AA047 AY Z-Board TNP2AA010 AJ

550x479x491.5

21.7 x 18.9 x 19.4

75Ω, phono jack

p-p

Table 1. Receiver Features

Specifications are subject to change without notice or obligation. Dimensions and weights are approximate.

- 6 -

Location of Controls (Receiver)

4 532

Remote Control

Sensor

Figure 2. Location of Controls (Receiver).

Quick Reference Control Operation

Quick Reference

Control Operation

Power Button - Press to turn ON or OFF. Volume Buttons - Press to adjust Sound Level, or to adjust Audio Menus, Video

Menus, and select operating features when menus are displayed Channel Buttons - Press to sele ct programme d channels. Pre ss to highlight d esired

features when menus are dis play ed. Also us e to selec t Cable Conv erte r box chan nels

after programming Remo te Control Infra-red codes ( the TV/AUX/CABLE switc h must be set in CABLE position).

Action Button - Press to display Main Menu and access On Screen feature and

Adjustment Menus.

TV/Video Button - Press to select TV or Video Input.

- 7 -

Location of Controls (Remote )

Power Button

Press to turn ON and OFF.

ACTION Button

Press to display Main Menu and

access or exit On Screen features

and Adjustment Menus.

TV, VCR, DBS/CBL, DVD

Component function buttons.

VOL (volume) Buttons

Press to adjust TV sound level.

Use with Channel buttons to

navigate in menus.

Mute Button

Press to mute sound. A second press resumes sound. Press also to access and delete

Closed Caption display.

R-TUNE (Rapid Tune) Button

Press to switch to the previous

channel.

LIGHT Butt o n

Press to light remote control buttons.

TV/VIDEO Button

Press to select TV or Video input.

CH (channel) Buttons

Press to select channels.

Use with volume buttons to

navigate in menus.

DBS EXIT, DBS GUIDE

DBS function buttons.

RECALL Button

Press to display Time, status

of Sleep Timer, Channel,

Video mode and Channel

Caption (Station Identifier).

“0” - “9”

Press numeric keypad to select any

channel.

REW, PLAY, FF, TV/VCR, STOP,

PAUSE, REC, VCR/DBS CH

Component function buttons.

Figure 3. Location of Controls (Remote).

EUR511502

- 8 -

Disassembly for Service

Back Cover

Remove all the screws marked with an arrow( ) from the back of the Receiver.

Note: Screw configuration, type, and number of

screws vary depending on the model of the Receiver serviced and the app lication; various models are covered in this Manual. Us e same hardware when reassembling the receiver.

• 2 screws at the top edge of the Receiver.

• 1 screw at each lower corner of the Receiver.

• 1 screw by the A/V jacks.

• 1 screw by the Fly-back assembly.

A-Board - Main Chassis

1. Slide the chassis completely out of the guide rails.

2. Stand the Receiver on its edge. The underside o f the board is completely accessible for component replacement.

Note: Some tie-wraps t hat secure the wire d ressings

may need to be unfastened for chassis removal.

C-Board - CRT Output

Plugs into the socket on the CRT neck.

Z-Board - Pincushion Correction

Plugs into the A-Board.

Speakers

Speaker are secured to the s peak er brac ket with 4 screws, the bracket is secured to the cabinet’s front with 2 screws.

Keyboard Push Button Assembly

Fastened to the inside of the cabinet front with up to 3 screws.

Disassembly for CRT Replacement

1. Discharge the CRT as instructed in the Safety Precautions (see page 2).

2. Disconnect the yoke (DY) plug, degaussing coil (DEG) plug and the CRT 2nd anode button from the main board.

3. Remove the C-Board from the CRT base and unplug the black wire (CRT dag ground) C10.

4. Disconnect the A11, A12, and Speakers plugs from the A-Board.

5. Lift the Main Chassis (A-Board) and all mounted boards completely out with the CRT Board attached.

CRT Replacement

1. Perform Disassembly for CRT Replacement procedure.

2. Insure that the CRT H.V. Anode button is discharged before handling the CRT. Read the Safety Precautions (see page 2) on handling the picture tube.

3. Remove the components from the CRT neck and place the cabinet face down on a soft pad.

4. Note the original order for the CRT mounting hardware as they are remove from the CRT mounting brackets at each corner of the CRT.

5. Remove the CRT with the dega ussing co il and th e dag ground braid attached.

6. Note the original locations and mounting of the degaussing coil and the dag ground assembly to insure proper reinstallation on the replacement CRT.

To remove and re-mount the degaussing coil:

The degaussing co il is held in place by clampers fastened to the CRT corner ears. These c lampers must be installed onto th e replacement CRT prior to mounting the degaussing coil.

To remove and re-mount the dag ground braid:

a.Unhook the coil sprin g from the bottom corners

of the CRT ears.

b.Release the braid loop from the upper corners of

the CRT ears.

7. Mount the dag ground braid on the replacement CRT. Position the degaussing coil with new ties. Dress coil as was on the original CRT.

8. Replace the components on CRT neck and reinstall into cabinet. Verify that all ground wires and circuit board plugs get connected.

- 9 -

Chassis Service Adjustment Procedures

All service adjustments are factory preset and should not require adjustment unless controls and/or associated components are replaced.

Note: Connect the (-) lead of the voltmeter to the appropriate ground. Use IC803’ s heat sink when the HOT ground

symbol ( ) is used. Otherwise, use COLD ground ( ) — Tuner shield, IC451’s heat sink or FA2.

A-BOARD

Figure 4.

A-Board Main Components and Test Points

IC6501

IC001

IC551

C572

IC2302

IC101

IC803

U N E R

C552

IC451

C809

TPD9

TPD8

Q551

MOMENTARILY CONNECT A JUMPER FOR ENTERING SERVICE MODE (FA1 to FA2 )

132.0V B+ Voltage Confirmation

Adjust Picture Menu for normalized video adjustments.

1. Set the Bright and the Picture to Minimum by using the Picture Menu.

2. Connect the DVM between C809(+ sid e) and cold ground ( ).

3. Confirm that B+ voltage is 132.0V ± 2.5V. This voltage supplies B+ to the Horizontal Output & Flyback circuits.

Source Voltage Chart

120V AC line input. Se t the Bright and the Picture to

High Voltage Check

1. Select an active TV channel and confirm that horizontal is in sync.

2. Adjust Brightness and Picture using Picture Icon menu so video just disappears.

3. Confirm B+ 131V is within limit.

4. Using a high voltage meter confirm that the High Voltage is 27.7kV ± 1.25kV.

Minimum by using th e Picture Menu. Use cold ground

(

) for the (-) lead of the DVM.

LOCATION VOLTAGE

TPD8 24.0V ± 2V TPD9 13.0V ± 2V C552 (+) side 8.0V ± 1V IC551 Pin3 9.0V ± 0.5V

D554

D554 Cathode 200V ± 15V C572 (+) side 5.0V ± 0.25V

- 10 -

Purity and Convergence Procedure

Adjustment is necessary only if the CRT or the deflection yoke is replaced or if the setting was disturbed. The complete procedure consists of:

1. Vertical Raster Shift Adjustment. (Only for Models

with Purity/Convergence Assembly with 4 Pairs of Rings).

2. Initial static convergence.

3. Setting the purity.

4. Final static convergence.

When the CRT or the Yoke is Replaced

Place the yoke on the CRT neck (do not tighten the clamp).

For a 2-piece assembly (see Fig. 5):

Position purity/convergence assembly as shown and tighten clamp snugly. Remove the hot-melt glue seal on assembly and position like tabs of purity device

together at 12 o’clock to reduce its magnetic field effect.

R&B Convergence Rings

R&B&G Convergence Rings

G3 G4

Purity Rings Centered

Over G3/G4 Gap

For a 1-piece assembly (see Fig. 8):

Position like tabs of purity devices together at 12

o’clock to reduce an y magnetic field effect. (For better results, note part numb er and look fo r specif ications at Service Center)

Figure 8. Positioning of Purity/Convergence

Assembly (1-piece assembly)

For either assemblies:

Turn the Receiver ON. Operate the Receiver for 60 minutes using the first Purity Check field (white screen) to stabilize the CRT. Fully degauss the Receiver by using an external degaussing coil.

Slide the defle ction yoke back and forth on t he ne ck o f the CRT until it produces a near white, uniform raster.

Figure 5. Positioning of Purity/Convergence Assembly

(2-piece assembly)

For models using 4 pairs of rings, place the vertical

raster shift tabs at 3 o’clock (90

from the purity and

convergence tabs, see Fig. 6 and Fig. 7)

R&B Convergence Rings

R&B&G Convergence Rings

Vertical Raster Shift Ring

G3 G4

Purity Rings Centered Over G3/G4 Gap

Figure 6. Positioning of Purity/Convergence Assembly

(4 Pairs of Rings)

R&B&G Convergence Rings

R&B Convergence Rings

Vertical Raster

Shift Rings

Purity Rings

Figure 7. Positioning of Purity/Convergence Assembly

(4 Pairs of Rings)

Vertical Raster Shift Adjustment (Only for

Models with Purity/Convergence Assembly with 4 Pairs of Rings).

Apply a green pattern with a horizontal line, adjust the Deflection Yoke so that has no tilt, then secure it. Adjust center line of the pattern with the mechanical center of the CRT, this center is determined by two marks at the side edges of the screen. To adjust the line, once the vertical raster shift tabs are place at 3 o’clock to reduce its magnetic field effect (see Fig. 6 and Fig. 7) open the tabs the same angle from the center, until the center line of the pattern becomes a straight line, center ed with the marks of the CRT. ( see Fig. 9)

Center line

from pattern

Mechanical

Center Marks

Vertical Raster Shift tabs

Figure 9. Vertical Raster Shift Adjustment

(4 pairs of rings assembly)

Open the same angle

from center

- 11 -

Initial Center Static Convergence

NOTES:

1. CRT warm up with white screen (three guns activated) is needed to stabilize the shadow mask expansion.

2. Initial center static convergence (roughly centers three gun beams) is required in order to perform purity adjustment.

Figure 10. Green Raster Adjustment

Green Raster

Connect a dot/cross hatch generator to the Receiver and tune in a signal. Observe misconvergence at center of the screen o nly. Adjust the R&B pole magne ts; by separating tabs and rotating to converge blue with red. Adjust the R&B and R&B&G pole magnets: by separating tabs and rotating to converge blue an d red (magenta) with green.

Note: Precise convergence at this point is

not important.

Purity Adjustment

When the Receiver is in the Service Mod e for making electronic adjustments, press the Recall but ton on the Remote Control to enter Purity Check. (See the

Service Adjustments Electronic Controls

procedure). Operate the Receiver for 60 minutes using the first Purity Check field (white screen) to stabilize the CRT. Fully degauss the Receiver by using an external degaussing coil. Press the Recall button on the Remote Control again until the Purity Check (green screen) appears.

For a 2-piece assembly (see Fig. 5): Loosen the deflection yok e clamp screw an d move the deflection yoke back as close to the purity magnet

as possible. Adjust the Purit y rings to set the vertical green raster precisely at the center of the screen (see Fig. 10).

Slowly move the deflecti on yoke forward until the best overall green screen is displayed.

For a 1-piece assembly (see Fig. 8):

Slowly move the deflection yoke and purity rings assembly toward the CRT board and adjust the purity magnet rings to set vertical green raster at center of screen (see Fig. 10). Gradually move the deflection yoke & purity rings forward and adjust for best overall green screen.

Continue from here for either assemblies:

Tighten the deflection yoke clamp screw. Press the Recall button on the Remote Control again until the purity check (blue screen) and (red screen) appear and observe that good purity is obtained on each respective field. Press the Recall button on the Remote Control again until Purity check (white screen) app ears. Obse rve the screen for uniform white. If purity has not been achieved, repeat the above procedure.

Final Convergence Procedure (see Fig. 11

through Fig. 13):

Note: Vertical size and focus adjustments must be completed prior to performing the convergence adjustment. Connect a dot pattern generator to the Receiver. The Brightness level should not be higher than necessary to obtain a clear pattern.

Converge the red and the blue dots at the center of the screen by rotating the R&B pole Static Convergence Magnets. Align The converged red/blue dots with the green dots at the center of the screen by rotating the R&B&G pol e Static Convergence Magnets. Melt wax with soldering iron to reseal the magnets. Slightly tilt vertica lly and ho rizontally (do not ro tate) the deflection yoke to obtain a good overall convergence. If convergence is not reached at the edges, insert permalloy (see fo llowing section) from the DY corners to achieve proper convergence. Recheck for purity and readjust if necessary. After vertical adjustment of the yoke, insert wedge at 11

o’clock position, then make the horizontal tilt adjustment. Secure the deflection yoke by inserting two side wedges at 3 and 7 o’clock positions. Apply adhesive between tab (thin portion) of wedge and CRT and place tape over the tab to secure to the CRT.

Permalloy Convergence Corrector Strip (Part No. 0FMK014ZZ)

This strip is used in some sets to match the yo ke and CRT for optimum convergence. If the y oke or CRT is replaced, the strip may not be required. First converge the set without the strip and observe the corners.

If correction is needed:

1. Place strip between CRT and yoke, in quadrant needing correction. Slowly move it around for desired results.

2. Press adhesive tightly to the CRT and secure with tape.

- 12 -

As the yoke is tilted

RGB

Figure 11. Vertical Yoke Movement

vertically, the rasters produced by the outside guns rotate in opposite directions.

RGB

As the yoke is tilted horizontally, one raster gets larger while the other gets smaller

Figure 12. Horizontal Yoke Movement

Raster produced from one of the outside electron beams

Raster from the other side electron beam

Static convergence magnets are set for center convergence

Static Convergence Magne t s Converges

R/B with G

Purity/Convergence

Assembly Clamp

Purity Rings Adj. on

Green Raster

11 o’clock Position

Converges

R with B

Double sided adhesive tape

3 o’clock Position

Y oke Positioning Wedges for Dynamic Convergence

7 o’clock Position

Figure 13. Convergence Magnets and Wedges Location

Note: For models using 4 pairs of rings

assemblies see Fig. 6 for details

- 13 -

Service Mode (Electronic Controls)

This Receiver has electronic technology using the I²C Bus Concept. It performs as a control function and it replaces many mechanical controls. Instead of adjusting mechanical controls individually, many of the control functions are now performed by using “On Screen Display Menu”. (The Service Adjustment Mode.)

Note: It is suggested that the tech nician reads all the way through and understand the following procedur e for

Entering/Exiting the Service Adjustment Mode; then proceed with the instructions working with the Receiver. When becoming familiar with the pr ocedur e , the Flow Chart for Ser vic e Mod e may be use d as a quick guide.

Quick Entry to Service Mode:

At times when minor adjustments need to be don e to the electronic controls, the method o f Entering the servic e Mode without removal of the cabinet back is as follows using the Remote Control:

1. Select SET-UP icon and select CABLE mode.

2. Select TIMER icon and set SLEEP time for 30 Min.

3. Press ACTION button twice to exit menus.

4. Tune to the Channel 124.

5. Adjust VOLUME to minimum (0).

6. Press the VOL button (decrease) on Receiver. Red “CHK” appears in upper corner.

To toggle between Aging and Service modes:

While the “CHK” is displayed on the left top corner of the CRT, pressing the Action and the Volume Up buttons on the Receiver simu ltaneously will toggle be tween the modes. Red “CHK” for Service and yellow “CHK ” for Aging.

7. Press the Power Button on the Remote Control to select one of six Service Adjustment Modes.

1) B= Service VCJ SUB-DATA ADJUSTEMENT.

2) C= Service VCJ CUT-OFF ADJUSTMENT.

3) S= Service OPTIONS (PIP and CLOCK) ADJUSTMENT.

4) M= Service MTS ADJUSTMENTS.

5) X = Service COMB FILTER ADJUSTMENT.

6) “CHK” = Normal operation of CHANNEL and VOLUME .

Note: Only the applicable settings for

32 B 0 2 215 C 0

the Receiver serviced will be available (See

in Fig. 14).

An address Menu appears in the right hand corner of the screen

Figure 14. Service Mode Menu Adjustments.

Exiting the Service Mode:

Press the Action and the Power buttons on the Receiver simultaneously for at least 2 seconds. THE RECEIVER EXITS SERVICE MODE.

The Receiver momentarily shuts off; then comes back on tuned to channel 3 with a preset level of sound. Any programmed channels, channels caption data and some others user defined settings will be erased.

IMPORTANT NOTE: Always Exit the Service Mode Following Adjustments.

- 14 -

+ 32 hidden pages