Hitachi pa0138 schematic

+,7$&+,

No. 0138

27GX01B-501

SERVICE MANUAL

176&

1$&+$66,6

27GX01B-511

R/C:

CLU-351U

CAUTION: Before servicing this chassis, it is important that the service technician read the “Safety

Precaution” and “Product Safety Notices” in this Service Manual.

This television will display television Closed

Captioning ( or ) in accordance

with paragraph 15.119 of the FCC rules.

CONTENTS

SAFETY PRECAUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

PRODUCT SAFETY NOTICE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

POWER SOURCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

SERVICE NOTES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

SERVICE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

CIRCUITS AND BLOCK DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . 32

PARTS IDENTIFICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

PARTS LIST. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT

SOLID STATE COLOR TELEVISION

JUNE 2000 HHEA-MANUFACTURING DIVISION

SAFETY PRECAUTIONS

NOTICE: Comply with all cautions and safety-related

notes located on or inside the cabinet and on the chasis or picture tube.

WARNING: Since the chasis of this receiver is connected to one side of the AC power supply during operation, whenever the receiver is plugged in, service shoul d not be attempted by anyone unfamiliar with the precautions necessary when working on this type of receiver.

The following precautions should be observed:

1. Do not install, remove, or handle the picture tube in any manner unless shatterproof goggles are worn. People not so equipped should be kept away from the picture tube while handling.

2. When service is required, an isolation transformer should be inserted between power line and the receiver

before any service is performed on a “HOT” chassis receiver.

3. When replacing a chassis in the receiver, all protective devices must be put back in place, such as barriers, nonmetallic knobs, adjustment and compartment covershields, isolation resistors, capacitors, etc.

4. When service is required, observe the original lead dress in the high voltage circuitry area.

Leakage Current Hot Check

Plug the AC cord directly into a 120V AC 60Hz outlet (do not use an isolated transformer for this check). Turn the AC power ON. Using a Leakage Current Tester (Simpson’s Model 229 or equivalent), measure for current from all exposed metal parts of the cabinet (antennas, screwheads, overlays, control shafts, etc.). Any current measured must not exceed 0.5 milliamps.

(READING

SHOULD NOT BE

ABOVE 0.5mA)

DEVICE UNDER

TEST

EXPOSED METAL

2-WIRE CORD

ALSO TEST WITH PLUG REVERSED (USING AC ADAPTER PLUG AS REQUIRED)

TEST ALL

SURFACES

LEAKAGE

CURRENT

TESTER

EARTH

GROUND

5. Always use the manufacturer’s replacement components. Critical components as indicated on the circuit diagram should not be replaced by another manufacturer’s. Furthermore, where a short circuit has occurred, replace those components that indicate evidence of overheating.

6. Before returning a serviced receiver to the customer, the service technician must thoroughly test the unit to be certain that it is completely safe to operate without danger of electrical shock, and be sure that no protective device built into the receiver has become defective, or inadvertently defeated during servicing.

Therefore, the following checks should be performed for the continued protection of the customer and service technician.

Leakage Current Cold Check

With the AC plug removed from the 120V AC 60Hz source, place a jumper across the two plug prongs. Turn the AC power switch ON. Using an insulation tester (DC500V), connect one lead to the jumpered AC plug and touch the other lead to each exposed metal part (antennas, screwheads, metal overlays, control shafts, etc.), particularly any exposed metal part having a return path to the chassis should have a minimum resistor reading of

0.24MΩ and a maximum resistor reading of 12MΩ. Any

resistance value below or above this range indicates an abnormality which requires corrective action. An exposed metal part not having a return path to the chassis will indicate an open circuit.

AC LEAKAGE TEST ANY MEASUREMENTS NOT WITHIN THE LIMITS

OUTLINED ABOVE ARE INDICATIVE OF A POTENTIAL SHOCK HAZARD AND MUST BE CORRECTED BEFORE RETURNING THE RECEIVER TO THE CUSTOMER.

High voltage

This receiver is provided with a hol d down circuit for clearly indicating that voltage has increased in excess of a predetermined value. Comply with all notes described in this service manual regarding this hold down circuit when servicing, so that this hold down circuit is operated correctly.

Serviceman Warning

With minimum BRIGHTNESS, CONTRAST, SHARPNESS, and COLOR, the operating high voltage in this receiver is lower than 28.30kV ±1.25kV. In case any component having influence on the high voltage is replaced, confirm that high voltage with minimum BRIGHTNESS, CONTRAST, SHARPNESS, and COLOR is lower than 28.30kV ±1.25kV. To measure high voltage use a High Impedance High Voltage meter. Connect (-) to chassis earth and (+) to the CRT ANODE button. (See the connection diagram on page 4.)

Note: Turn power switch OFF without fail before the connection to the Anode Button

- 2 -

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

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

Product Safety Notice . . . . . . . . . . . . . . . . . . . . 4

Horizontal Oscillator Disable Circuit . . . . 5

Receiver Feature Table . . . . . . . . . . . . . . . . . . . 6

Location of Controls (Receiver)

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

Location of Controls (Remote). . . . . . . . . . . . . 8

Disassembly for Service. . . . . . . . . . . . . . . . . 13

Disassembly for CRT Replacement . . . . . . . . 13

Chassis Service Adjustment Procedures . . . 14

131.0V B+ Voltage Confirmation . . . . . 14

Source Voltage Chart . . . . . . . . . . . . . . 14

B+ 5V Source Voltages. . . . . . . . . . . . . 14

MPU 5V . . . . . . . . . . . . . . . . . . . . . . . . 14

Stand-by 5V . . . . . . . . . . . . . . . . . . . . . 14

B+ 9V Source Voltage . . . . . . . . . . . . . 14

B+ 12V (Stand-by) . . . . . . . . . . . . . . . . 14

High Voltage Check . . . . . . . . . . . . . . . 14

Purity and Convergence Procedures . . . . . . 15

Service Adjustments

(Electronic Control). . . . . . . . . . . . . . . . . . 28

Sub-Brightness. . . . . . . . . . . . . . . . . . . 28

Sub-Contrast. . . . . . . . . . . . . . . . . . . . . 28

Tint/Color Adjustment . . . . . . . . . . . . . . 28

Color Temperature Adjustment. . . . . . . 29

Horizontal Centering. . . . . . . . . . . . . . . 30

MTS Circuit Adjustment . . . . . . . . . . . . 30

Clock Adjustment (S7) . . . . . . . . . . . . . 31

Vertical Size . . . . . . . . . . . . . . . . . . . . . 31

Service Adjustments

(Mechanical Controls). . . . . . . . . . . . . . . . 31

Focus (Part of T551). . . . . . . . . . . . . . . 31

Audio Signal Path Block Diagram . . . . . . . . . 32

Video-Chroma Signal Path

Block Diagrams. . . . . . . . . . . . . . . . . . . . . 33

IC101 VCJ IN/OUT Pins and Functions . . . . . 34

IC001 MPU IN/OUT Pins and Functions. . . . . 35

Components Identification . . . . . . . . . . . . . . . 36

Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Serviceman Mode (Electronic Controls) . . . . 18

Entering Serviceman Mode . . . . . . . . . 18

Toggle between Modes. . . . . . . . . . . . . 18

Exiting the Serviceman Mode. . . . . . . . 18

Sub-Data Adjustment . . . . . . . . . . . . . . 19

Cut-Off Adjustment. . . . . . . . . . . . . . . . 19

Pin Cushion Adjustment . . . . . . . . . . . . 20

MTS Adjustment. . . . . . . . . . . . . . . . . . 20

PIP Adjustment. . . . . . . . . . . . . . . . . . . 21

Options Adjustment . . . . . . . . . . . . . . . 22

Comb Filter Adustment. . . . . . . . . . . . . 23

To Check Purity . . . . . . . . . . . . . . . . . . 24

Helpful Hints . . . . . . . . . . . . . . . . . . . . . 24

Instructional Flow Chart

for Serviceman Mode . . . . . . . . . . . . . . . . 25

- 3 -

PRODUCT SAFETY NOTICE

HIGH

IMPEDANCE

H.V. METER

CRT ANODE

CHASSIS GROUND

CRT

Many electrical and mechanical parts in HITACHI television receivers have special safety-related characteristics. These are often not evident from visual inspection nor can the protection afforded by them necessarily be obtained by using replacement components rated for higher voltage, wattage, etc. Replacement parts which have these special safety characteristics are identified in this Service manual.

Electrical components having such features are identified with a mark in the schematics and parts list in this

Service Manual. The use of a substitute replacement component which

does not have the same safety characteristics as the HITACHI recommended replacement component, shown in the parts list in this Service Manual, may create shock, fire, X-radiation, or other hazards.

Production safety is continuously under review and new instructions are issued from time to time. For the latest information, always consult the current HITACHI Service Manual. [A subscription to, or additional copies of HITACHI Service Manuals may be obtained at a nominal charge from HITACHI Sales Corporation.]

This Service Manual is intended for qualified service technicians; it is not meant for the casual do-it-yourselfer. Qualified technicians have the necessary test equipment and tools, and have been trained to properly and safely repair complex products such as those covered by this manual. Improperly performed repairs can adversely affect the safety and reliability of the product and may void warranty. Consumers should not risk trying to do the necessary repairs and should refer to a qualified service technician.

WARNING

Lead in solder used in this product is listed by the California Health and Welfare agency as a known reproductive toxicant which may cause birth defects or other reproductive harm (California Health and Safety Code, Section 25249.5).

When servicing or handling circuit boards and other components which contain lead in solder, avoid unprotected skin contact with solder. Al so, when soldering do not inhale any smoke or fumes produced.

SAFETY NOTICE

USE ISOLATION TRANSFORMER

WHEN SERVICING

X-Radiation

TUBE: The primary source of X-Radiation in this receiver

is the picture tube. The tube utilized in this chassis is specially constructed to limit X-Radiation emissions. For continued X-Radiation protection, the replacement tube must be the same type as the original HITACHI-approved type.

When troubleshooting and making test measurements in a receiver with excessive high voltage problem, avoid being unnecessarily close to the picture tube and high voltage components.

Components having special safety characteristics identified by on the parts list in this service manual and

its supplements and bulletins. Before servicing this product, it is important that the service technician read and

follow the “Safety Precautions” and the “Product Safety Notices” in this Service Manual.

For continued X-Radiation protection, replace picture tube with original type or HITACHI equivalent type.

POWER SOURCE

This television receiver is designed to operate on 120Volt/ 60Hz, AC house current. Insert the power cord into a 120Volts/60Hz outlet.

NEVER CONNECT THE TV TO OTHER THAN THE SPECIFIED VOLTAGE OR TO DIRECT CURRENT.

Do not operate the chassis longer than is necessary to locate the cause of excessive voltage.

- 4 -

Service Notes

IMPORTANT: To protect against possible damage to

the solid state devices due to arcing or static discharge, make certain that all ground wires an d CRT DAG wire are securely connected.

Equipment needed to check the disabled circuit:

1. Voltmeter (0 - 200V scale)

2. High Voltage Meter (0 - 50kV)

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.

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.

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

parts indicated with the s ymbol must be replaced with identical parts. Order parts from

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

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

on the schematic

Horizontal Oscillator Disable Circuit

3. Variac or Isolation Transformer

Procedure:

1. Tune in a station to verify that the horizontal is

in sync.

2. Obtain a Monoscope pattern or a signal generator

crosshatch pattern

3. Set Bright and Picture level to zero (0).

4. Turn the Receiver OFF. Connect a jumper across

IC803 pin 3 and pin 4. Apply +9V DC to cathode of

D001.

5. Reduce the AC supply voltage to approximately

45V. Connect the high voltage meter to the CRT

anode. (H.V. button).

Note: Use the Dag Ground (C10 on the CRT Board)

to connect the (-) lead of the meter.

6. Turn the Receiver ON. Slowly increase the AC

supply voltage and verify that the high voltages

does not exceed 37.1kV, when horizontal just

begins to pull ou t of sync . If the hig h voltage is not

within the specified limit, the cause must be

determined and corrected before the Receiver is

returned to the customer.

This chassis employs a special circuit to protect against excessive high voltage and beam current. If, for any reason, the high voltage and beam current e xc ee d a predetermined level this protective circuit activates and detunes the horizontal oscillator that limits the high voltage. The over-voltage protection circuit is not adjustable. However, if components indicated by the

symbol sweep system or the over-voltage protection circuit itself are changed, the operation of the circuit should be checked using the following procedure:

on the schematic in either the horizontal

- 5 -

Receiver Feature Table

FEATURE\MODEL

Chassis NA8 Tuning system 96K # of channels 181 Menu language Eng/Span/Fr Closed Caption X V-Chip X 75 Ω input X Remote Model # HL00761 Picture tube M68LGLO61X V/A norm (X=both) X MTS/SAP/DBX X Volume Correction X Built-in audio power 5Wx2 (10%) # of speakers 2 A/V in (rear/front) 3(2/1) Dimensions mm

(HxWxD) in

27GX01B-501 27GX01B-511

594.8x665.2x544.5

23.4x26.1x21.4

Weight (kg/lbs) 38/83.6 Power source (V/Hz) 120/60 Anode voltage

Video input jack Audio input jack 500mV RMS 47kΩ A-Board TNP2AH017 AD C-Board TNP2AA047 AP

28.30kV ±1.25kV

75Ω, phon o 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)

1 2 3 4 5 6

Figure 1. 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 selec t programmed c hannels. Pres s to highlight de sired

features when menus are displayed.

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

Adjustment Menus.

Input Button - Press to select TV or one of two Video Inputs.

Front A V In Jacks - Front audio, video and earphone jacks.

- 7 -

Location of Controls (Remote )

REMOTE CONTROL

Power Button

Press to turn On or Off.

Mute Button

Press to mute sound. A second press resumes sound. Pr ess also to toggle Closed Captioning.

Input Button

Press to select TV or video input.

Menu Button

Press to display main menu and access or exit onscreen features or Adjustment menus.

Recall Button

Press to display Time status of sleep timer, channel, video mode, channel I.D. and audio mode.

Precoded VCR Buttons

These buttons transmit the chosen precoded VCR codes.

POWER TV CABLE VCR

789

MUTE

RECALL

REC

TV/VCR

LST-CH

SLEEPINPUT

STOP

tt t uu

CURSOR CONTROL

PAUSE

VOL

REMOTE CONTROL

Mode Buttons

These buttons allow the remote to control your TV, VCR, or cable box depending on which mod e button is selected.

Channel Buttons

Press to select channels.

Keypad Buttons

Press desired channel number to access channel .

Volume Buttons

Press to adjust TV sound level.

LST-CH (Last Channel) Button

Press to switch to the previously tuned channel.

Sleep Button

Press to turn TV Off in 30, 60, or 90 minutes.

HITACHI

CLU-351U

Figure 2. Location of Controls (Remote)

Cursor Button

Press to adjust Aud io menus, Video menus, and select operating features when menus are displayed.

- 8 -

Remote Control Quick Reference Functional Key Chart

321

Key Operates

POWER

INPUT

TV CABLE VCR

TV Selects the TV Input Mode

TV Activates and Exits TV Menus

VCR CABLE

Turns TV On and Off Turns Cable Box On and Off Turns VCR On and Off

Selects Channel Selects code in Video Lock Menu Selects Channel in Channel I.D. Menu Selects Channel in Timer Menu

Selects Precoded VCR codes when programming remote

Selects Precoded CABLE codes when programming remote

RECALL

TV Display Channel, Time, Channel I.D. and Audio Mode

TV Menu Navigation

TV CABLE

Channel Up/Down Channel Up/Down

VOL p

VOL q

TV Volume Up/Down

- 9 -

Key Operates

SLEEP

MUTE

LST-CH

Mode Selection Buttons

CABLE

VCR

TV Select previously tuned channel

TV CABLE VCR

Selects 30, 60 or 90 minutes for Automatic Turn Off. Also use to turn Sleep Timer off by selecting NO

Mutes TV Audio Access and exit Closed Caption ing

Selects TV Mode for the remote control Selects Cable Mode for the remote control Selects VCR Mode for the remote control

Standard VCR Control Buttons

REC

STOP

PAUSE

TV/VCR

VCR

VCR CABLE

Record

Rewind

Fast Forward

Play

Stop

Pause

Selects TV or VCR Mode Selects A/B Mode

- 10 -

Using the Remote to Control VCR and Cable box Funtions

Operating the Precoded Function for Your VCR

This remote is designed to operate different types of VCRs. You must first program the remote to match the remote system in your VCR. (Refer to the VCR Code Index section.)

1. Turn on your VCR.

2. Aim the remote control at the front of your VCR.

3. Press the VCR button to s witch to VCR precoded mode.

4. While holding down the VCR button, enter the 2-digit preset code that matches your VCR*. The remote will turn on your VCR when the correct 2-digit preset code is entered. When this occurs, the remote contr ol is programme d for your VCR. If your VCR does not turn off after 5 s econds, try a different 2-digit preset code.

5. The remote will now control your VCR.

NOTES:

• If your VCR cannot be operated after performing the above procedures, this means that your VCR codes have not been precoded into the remote.

• In the unlikely event that your VCR cannot be operated after performing the above pro cedures, consult your VCR operating guide.

• The remote control will remember the codes you have programmed in until the batteries ar e removed. After replacing the batteries repeat the entire programming proc edure stated above.

• If your VCR does not have a power function, the remote will issue the CHANNEL UP function.

POWER TV CABLE VCR

789

MUTE

RECALL

REC

TV/VCR

LST-CH

SLEEPINPUT

STOP

tt t uu

CURSOR CONTROL

PAUSE

VOL

HITACHI

CLU-351U

* (Codes are listed on page 12)

Operating the Precoded Function for Your Cable Box

1. Turn on your cable box.

2. Aim the remote control at th e fron t of your cable box.

3. Press the cable box button to switch to cable box precoded mode.

4. While holding down the CABLE button, enter the 2-digit preset code that matches your cable box*. The remote will turn on your cable box when the cor rect 2-digit preset code is entered. When this occurs, the remote control is programmed for your cable box. If your cable box does not turn off after 5 seconds, try a different 2digit preset code.

5. The remote will now control your cable box.

NOTES:

• If your cable box cannot be operated after performing the above procedures, this means that your cable box codes have not been precoded into the remote.

• In the unlikely event that your cable box cannot be operated after performing the above procedures, consult your cable box operating guide.

• The remote control will remember the codes you have programmed in until the batteries are removed. After replacing the batteries repeat the entire programm ing pr ocedure stated above.

• If your cable box does not have a power function, the remote will issue the CHANNEL UP function.

• For some models, the remote control’s channel and will control the cable box channel. The number buttons will control your television channel although you are in cable mode.

- 11 -

VCR and Cable Box Codes Index

The remote is capable of operating many brands of V CRs and cable boxes. You must first program the remote control to match the remote system in your VCR or cable box.

NOTE:

The remote control memory is limited. Some models of VCRs or cable bo xes may no t operate. The remote con trol is not designed to control all features that are available in all models.

Code Index For VCRs

VCR Brand Code (s)

Emerson

Funai GE Hitachi JVC Magnavox Mitsubishi Panasonic RCA Sony Toshiba Zenith

00,01,10,16,23,33, 37,40, 43

00 09,22 00,14,15 14,26 09,12,28 16,23,26,45 09,35,46 15,22 06,07,08,09 16,17,42 07,08,12

Code Index for Cable Boxes

Cable Box

Brand

G.I. Jerrold Magnavox Philips Pioneer Samsung Scientific Atlantic Zenith

Code(s)

09 03, 09, 10, 12, 13,

51 40 40 39 39 04, 06, 14, 52, 56 00

- 12 -

Disassembly for Service

Disassembly for CRT

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 a nd the appli cation; v arious models are covered in this Manual. Use same hardware when reassembling the receiver.

• 3 screws at the top edge of the Receiver.

• 1 screw at each lower corner of the Receiver.

• 1 screw by the retainer plate of the AC power cord.

• 1 screw by the Flyback assembly.

• 1 screw by the A/V jacks.

A-Board - Main Chassis

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

2. Stand the Receiver on its edge. The underside of the board is completely acc essible for component replacement.

Note: Some tie- wraps th at s ec ure t he wi r e dres s ing s

may need to be unfastened for chassis removal.

C-Board - CRT Output

Plugs into the socket on the CRT neck.

Speakers

Each speaker is sec ured to the cabinet’s front with 4 screws.

Keyboard Push Button Assembly

Fastened to the inside of the cabinet front wit h up to 3 screws.

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 th e CRT 2nd anod e 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 compon ents 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 removed from the CRT mounting brackets at each corner of the CRT.

5. Remove the CRT with the degaussi ng coil and the dag ground braid attached.

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

To remove and re-mount the degaussing coil:

The degaussing coil is hel d in place by clampers fastened to the CRT corner ea rs. These clampers must be installed on to the replacement CRT prior to mounting the degaussing coil.

To remove and re-mount the dag ground braid:

a.Unhook the coil spri ng from the bottom corne rs

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 re-install into cabinet. Verify that all ground wires and circuit board plugs get connected.

- 13 -

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

COLD ( )

HOT ( )

RL801

F801

IC 803

C552

C809

TPD9

TPD8

IC 002

A32

IC 6501

IC 001

164

32 33

A31

T U N E R

FA1

DAT A

TP15

A11

IC 101

152

26 27

CLK

FA2

IC 551

IC 552

IC 2302

Figure 3. A-Board Main Components and Test Points

IC 4402

A61

IC 2321

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

IC 451

Q501

FOCUS SCREEN

Q551

D554

131.0V B+ Voltage Confirma tion

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 131.0V ± 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 Minimum by using th e Picture Menu. Use cold ground

(

) for the (-) lead of the DVM.

C572 (+) +5.0V ± 0.25V

TPD9 +13.0V ± 2V C552(+) +8.0V ± 1V TPD8 +27.4V ± 2V IC551 pin3 +9.0V ± 0.5V CATHODE OF D554 +220.0V ± 15V

Adjust Picture Menu for normalized video adjustments.

B+ 5V Source Voltages Volatile 5V:

C572, + side = IC552 pin 3, Tuner BP, IC101 (IF 5V).

MPU 5V:

Emitter Q002 = IC001 (VDD, AVDD).

Stand-by 5V:

IC001 (key in 1), I2C EEPROM (IC002), Remote Receiver.

B+ 9V Source Voltage

IC551 pin 3 = IC101 (IF 9V), Tuner (BM).

B+ 12V (Stand- by)

Note: +16V when power is on

Cathode D001 = RL801 (on-off relay), Q002 (+5V Reg).

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

28.30kV ±1.25kV.

- 14 -

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. 4):

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. 7):

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 7. 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 4. 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. 5 and Fig. 6)

R&B Convergence Rings

R&B&G Convergence Rings

Vertical Raster Shift Ring

G3 G4

Purity Rings Centered Over G3/G4 Gap

Figure 5. 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 6. 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. 5 and Fig. 6) 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. 8)

Center line

from pattern

Mechanical

Center Marks

Vertical Raster Shift tabs

Figure 8. Vertical Raster Shift Adjustment

(4 pairs of rings assembly)

Open the same angle

from center

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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 9. 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 only. 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 Serviceman Mode for making electronic adjustments, press the Recall button on the Remote Control to ente r Purity Check. (Se e 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. 4): 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. 9).

Final Convergence Procedure (see Fig. 10

through Fig. 12):

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)

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

For a 1-piece assembly (see Fig. 7): Slowly move the deflection yoke and purity rings

assembly toward the CRT board and adju st the purity magnet rings to set vertical green raster at center of screen (see Fig. 9). 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.

This strip is used in some sets to match the yoke 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.

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