Sanyo DS27910 Schematic

FILE NO.

SERVICE MANUAL Remote Control Color

Television

DS27910 (U.S.A.)

ORIGINAL VERSION

Chassis No. 27910-00

NOTE: Match the Chassis No. on

the unit’s back cover with the Chassis No. in the Service Manual.

If the Original Version Service Manual Chassis No. does not match the unit’s, additional Service

Literature is required. You must refer to “Notices” to the Original Service Manual prior to servicing the unit.

Contents

Safety Instructions . . . . . . . . . . . . . . . . . . 2

Service Adjustments. . . . . . . . . . . . . 3 - 10

Service Hints. . . . . . . . . . . . . . . . . . . . . . 10

Mechanical Disassemblies. . . . . . . . . . . 11

Chassis Electrical Parts List . . . . . . 12 - 22

Cabinet Parts List . . . . . . . . . . . . . . . . . . 23

Component and Test Point

Locations . . . . . . . . . . . . . . . . . . . 24 - 27

Schematic Insert . . . . . . . . . . . . . . . 29 - 36

Schematic Notes . . . . . . . . . . . . . . . . . 29

Pin Layouts . . . . . . . . . . . . . . . . . . . . . 25

Capacitor and Resistor Codes . . . . . . 29

Block Diagram. . . . . . . . . . . . . . . 30 - 31

Voltage Charts . . . . . . . . . . . . . . . 30 - 32

Waveforms. . . . . . . . . . . . . . . . . . . . . . 32

Schematic Diagrams . . . . . . . . . . 33 - 36

Specifications

Power Rating . . . . . . . . . . . . . . . . . . . . . 120V, 60Hz

112W (Avg), 2.5A (Max)

Antenna Input Impedance . . . . . . . . . . . . . . . . 75W

UHF/VHF/CATV

Receiving Channel . . . . . . . . . . . . . . . . 2 - 13 (VHF),

14 - 69 (UHF),

01, 14-94, 95-125 (CATV)

Remote Ready . . . . . . . . . . 38 Key Remote Control

Sound Output . . . . . . . . . . . . . . . . . . . . . . 3.0 W/CH

Intermediate Frequency

Picture IF Carrier. . . . . . . . . . . . . . . . . . 45.75MHz

Sound IF Carrier . . . . . . . . . . . . . . . . . . 41.25MHz

Color Sub Carrier . . . . . . . . . . . . . . . . . 42.17MHz

Picture Tube . . . . . . . . . . . . . . . . . . A68ERF031X013

Semiconductors

Integrated Circuits. . . . . . . . . . . . . . . . . . . . . . . 12

Transistors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Except within Tuner and RC Pre-Amp.

Cabinet Dimensions

Width. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 664mm

Height . . . . . . . . . . . . . . . . . . . . . . . . . . . . 629mm

Depth. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 487mm

REFERENCE No. SM780074

DS27910,G7YAM, PRODUCT CODE 111357080

VOL

— 2 —

SAFETY PRECAUTIONS

WARNING: The chassis of this receiver has a floating ground with the potential of one half the AC line voltage in respect to earth ground. Service should not be attempted by anyone not familiar with the precautions necessary when working on this type of equipment.

The following precautions must be observed:

1. An isolation transformer must be connected in the power line between the receiver and the AC line before any service is performed on the receiver.

2. Comply with all caution and safety-related notes provided on the side of the cabinet, inside the cabinet, on the chassis, and the picture tube.

3. When replacing a chassis in the cabinet, always be certain that all the protective devices are installed properly, such as control knobs, adjustment covers, shields and barriers.

DO NOT OPERATE THIS TELEVISION RECEIVER WITHOUT THE PROTECTIVE SHIELD IN POSITION AND PROPERLY SECURED.

4. Before replacing the back cover of the set, thoroughly inspect the inside of the cabinet to see that no stray parts or tools have been left inside. Before returning any television to the customer, the service technician must perform the following safety checks to be sure that the unit is completely safe to operate without danger of electrical shock.

ANTENNA COLD CHECK

Remove AC plug from the 120 VAC outlet and place a jumper across the two blades. Connect one lead of an ohmmeter to the jumpered AC plug, and touch the other lead to each exposed antenna terminal (UHF and VHF antenna terminals). The resistance must measure between 1M ohm and

5.2M ohm. Any resistance value below or above this range

indicates an abnormality which requires corrective action.

LEAKAGE CURRENT CHECK

Plug the AC line cord directly into a 120 VAC outlet. (Do not use an isolation transformer for this check.) Use an AC voltmeter, that has 5000 ohms per volt or more sensitivity. Connect a 1500 ohm 10 watt resistor, paralleled by a 0.15 µF 150 VAC capacitor, between a known good earth ground (water pipe, conduit, etc.) and all exposed metal parts of the cabinet (antennas, handle bracket, metal cabinet, screw heads, metal overlays, control shafts, etc.). Measure the AC voltage across the 1500 ohm resistor. The AC voltage should not exceed 750 mV. A reading exceeding 750 mV indicates that a dangerous potential exists. The fault must be located and corrected. Repeat the above test with the receiver power plug reversed.

NEVER RETURN A RECEIVER TO THE CUSTOMER WITHOUT TAKING THE NECESSARY CORRECTIVE ACTION.

X-RADIATION PRECAUTION

The primary source of X-RADIATION in solid-state receivers is the picture tube. The picture tube is specially constructed to limit X-Ray emission. For continued X-RADIATION protection, the replacement tube must be the same type as the original (including the suffix letter in the part numbers). Excessive high voltage may produce potentially hazardous X-RADIATION. To avoid such hazards, the high voltage must be maintained within specific limits. Refer to the X-RADIATION WARNING NOTE on the CHASSIS SCHEMATIC in this service manual for specific high voltage limits. If the high voltage exceeds specified limits, check the components specified on the chassis schematic diagram and take the necessary corrective action. Carefully follow the instructions for the +B Voltage Check and the High Voltage Check to maintain the high voltage within the specified limits.

HIGH VOL T AGE HOLD-DOWN TEST

To prevent X-RADIATION from the picture tube due to excessive high voltage, a HOLD-DOWN circuit is provided in the high voltage circuit. Every time the receiver is serviced, the high voltage HOLD-DOWN circuit must be tested for proper operation. Refer to the HIGH VOLTAGE HOLDDOWN TEST in service adjustments.

PRODUCT SAFETY NOTICE

When replacing components in a receiver, always keep in mind the necessary product safety precautions. Pay special attention to the replacement of components marked with a star (★) in the parts list and in the schematic diagrams. To ensure safe product operation, it is necessary to replace those components with the exact same PARTS.

SAFETY INSTRUCTIONS

READING SHOULD NOT EXCEED 750 mV.

AC VOLTMETER

(5000 ohms per volt or more sensitivity)

TELEVISION

RECEIVER

Good earth ground such as a water pipe, conduit, etc.

AC OUTLET

1500 ohm

10 watt

0.15 µF 150V AC

To be touched to all of exposed metal parts. Voltmeter Hook-up for Leakage Current Check.

GENERAL

This set has an On-screen Service Menu system included in the CPU that allows remote operation for most of the service adjustments.

ON-SCREEN SERVICE MENU SYSTEM

1. Enter the Service Menu:

•While pressing the MENU key, reconnect the AC power cord. The Service Menu Display will now appear. (See Figure 1.)

2. Service Adjustments:

•Press the ▲ or ▼ key to select the desired service menu you want to adjust. (See page 4 for On-screen Service Menu.)

•Use the + or – key to adjust the data.

3. Exit from the Service Menu:

•Press the MENU key to turn off the Service Menu display.

SERVICE AD JUSTMENTS

— 3 —

IC802 (EEPROM) REPLACEMENT

When IC802 (EEPROM) is replaced, IC801 (CPU) will automatically write the initial reference data into IC802 for basic TV operation. However, the bus data should be checked and some bus data should be set up before attempting the service adjustments. (See pages 4 – 6 for detailed information.)

INITIAL BUS DATA SETUP

Note: When IC802 (EEPROM) is replaced, the following bus data must be set up for proper TV operation before attempt-

ing the service adjustments.

1. Disconnect the AC power cord (AC 120V line).

2. While pressing the MENU key, reconnect the AC power cord. The Service Menu display will now appear.

3. Select NO. 03 HP (H Phase) with ▲ or ▼ key. Adjust the data with + or – key for 12.

4. Select NO. 04 VS (V Size) with ▲ or ▼ key. Adjust the data with + or – key for 66.

5. Select NO. 05 VPO (V Position) with ▲ or ▼ key. Adjust the data with + or – key for 45.

6. Select NO. 11 HBR (H BLK R) with ▲ or ▼ key. Adjust the data with + or – key for 4.

7. Select NO. 19 GD (Green Drive) with ▲ or ▼ key. Adjust the data with + or – key for 12.

8. Select NO. 23 POS (Pre/Over/SW) with ▲ or ▼ key. Adjust the data with + or – key for 1.

9. Select NO. 29 WP (White Peak Limiter) with ▲ or ▼ key. Adjust the data with + or – key for 1.

10. Select NO. 34 DCR (DC Reset) with ▲ or ▼ key. Adjust the data with + or – key for 1.

11. Select NO. 35 YGM (Y Gamma) with ▲ or ▼ key. Adjust the data with + or – key for 2.

12. Select NO. 37 AF (Auto Flesh) with ▲ or ▼ key. Adjust the data with + or – key for 1.

13. Select NO. 41 RYA (R-Y/B-Y Angle) with ▲ or ▼ key. Adjust the data with + or – key for 2.

14. Select NO. 47 EWD (EW DC) with ▲ or ▼ key. Adjust the data with + or – key for 46.

15. Select NO. 48 EWA (EW Amp) with ▲ or ▼ key. Adjust the data with + or – key for 22.

16. Select NO. 49 EWT (EW Tilt) with ▲ or ▼ key. Adjust the data with + or – key for 36.

17. Select NO. 50 EWP (EW Corner Top) with ▲ or ▼ key. Adjust the data with + or – key for 5.

18. Select NO. 51 EWB (EW Corner Bottom) with ▲ or ▼ key. Adjust the data with + or – key for 7.

19. Select NO. 52 HSC (Horz Size Comp) with ▲ or ▼ key. Adjust the data with + or – key for 6.

20. Select NO. 57 OPT (SA Option ) with ▲ or ▼ key. Adjust the data with + or – key for 88.

21. Select NO. 58 OP2 (SA Option 2) with ▲ or ▼ key. Adjust the data with + or – key for 46.

22. Select NO. 60 ATT (Input Level) with ▲ or ▼ key. Adjust the data with + or – key for 9.

23. Select NO. 63 SBO (Sub Bright Offset) with ▲ or ▼ key. Adjust the data with + or – key for 2.

24. Press the MENU key to turn off the Service Menu display.

NO. DATA XX OPT XXX XXXXXXXX

Figure 1. Service Menu Display

ITEM NO.

TITLE

BINARY DATA (8 bit)

DECIMAL DATA

— 4 —

Table 1. ON-SCREEN SERVICE MENU

When IC802 (EEPROM) is replaced, check the bus data to confirm they are the same as below. The shaded menu should be checked and be set up or readjusted according to the procedures described in the following pages. Initial Setup Data marked with an * should be changed from Initial Reference Data. (See page 3 for Initial Bus Data Setup.)

NO. TITLE

INITIAL REFERENCE INITIAL SETUP

RANGE OF DATA FUNCTION

DATA DATA 01 HFR 29 29 0~63 Horizontal Frequency 02 AFC 0 0 0, 1 AFC Gain & Gate 03 HP 11 12* 0~31 Horizontal Phase (Horizontal Centering) 04 VS 64 66* 0~127 Vertical Size 05 VPO 32 45* 0~63 Vertical Position 06 VSP 0 0 0, 1 Vertical Set Up (Sync Sensitivity) 07 VLN 17 17 0~31 Vertical Linearity 08 CRS 0 0 0~3 Cross B/W 09 GRY 1 1 0, 1 Gray Mode 10 VSC 10 10 0~31 Vertical S Correction 11 HBR 3 4* 0~7 H BLK R 12 HBL 4 4 0~7 H BLK L 13 CDM 0 0 0, 1 C D Mode 14 VC 5 5 0~7 Vertical Compression 15 RB 0 0 0~255 Red Bias 16 GB 0 0 0~255 Green Bias 17 BB 0 0 0~255 Blue Bias 18 RD 64 64 0~127 Red Drive 19 GD 8 12* 0~15 Green Drive 20 BD 64 64 0~127 Blue Drive 21 SBI 64 64 0~127 Sub Bias 22 OSD 2 2 0~3 OSD Contrast 23 POS 0 1* 0, 1 Pre/Over/SW 24 FLS 2 2 0~7 Filter System 25 CKO 3 3 0~7 Color Killer Operation 26 GYA 0 0 0, 1 G-Y Angle 27 CRG 2 2 0~3 Coring Gain 28 PRE 1 1 0~3 Pre Shoot Adjust 29 WP 0 1* 0, 1 White Peak Limiter 30 FSW 0 0 0, 1 FBP Blanking Switch 31 VBL 0 0 0, 1 Vertical Blanking Switch 32 BSG 1 1 0~3 Black Str Gain 33 BSS 1 1 0~3 Black Str Start 34 DCR 0 1* 0~3 DC Reset 35 YGM 1 2* 0~3 Y Gamma 36 CBP 0 0 0, 1 C Bypass 37 AF 0 1* 0, 1 Auto Flesh 38 BAT 4 4 0~7 Bright ABL Threshold 39 MSD 0 0 0, 1 Mid Stop Def 40 ABL 0 0 0, 1 Auto Bright Limit 41 RYA 4 2* 0~15 R-Y/B-Y Angle 42 RAD 20 20 0~63 RF AGC Delay 43 IAS 0 0 0, 1 IF AGC 44 FMM 0 0 0, 1 FM Mute 45 FL 15 15 0~31 FM Level

— 5 —

Table 1. ON-SCREEN SERVICE MENU (Continued)

NO. TITLE

INITIAL REFERENCE INITIAL SETUP

RANGE OF DATA FUNCTION

DATA DATA 46 VL 4 4 0~7 Video Level 47 EWD 39 46* 0~63 EW DC 48 EWA 30 22* 0~63 EW Amp 49 EWT 34 36* 0~63 EW Tilt 50 EWP 7 5* 0~7 EW Corner Top 51 EWB 8 7* EW Corner Bottom 52 HSC 4 6* Horiz Size Comp 53 SB 32 32 0~63 Sub Bright 54 SCO 7 7 0~31 Sub Color 55 STI 20 20 0~31 Sub Tint 56 SSH 12 12 0~31 Sub Sharpness 57 OPT 0 88* 0~255 Option (See Note 1 page 6.) 58 OP2 0 46* 0~255 Option 2 (See Note 2 page 6.) 59 HR 24 24 0~63 OSD Horizontal Position 60 ATT 10 9* 0~63 Input Level 61 WDB 32 32 0~63 Wideband 62 SPC 32 32 0~63 Spectral 63 SBO 5 2* 0~255 Sub Bright Offset 64 PCO 40 40 0~63 PIP Color 65 PTI 40 40 0~63 PIP Tint 66 PUV 24 24 0~63 PIP Top Position 67 PDV 147 147 0~255 PIP Bottom Position 68 PLH 10 10 0~63 PIP Left Position 69 PRH 101 101 0~255 PIP Right Position 70 PCN 42 42 0~63 PIP Y Level 71 PBS 15 15 0~63 PIP BGP Phase

72 DRV

64 64 0~127 Red Drive Adjustment (See Note 3 page 6.) 64 64 0~127 Blue Drive Adjustment (See Note 3 page 6.)

– 0 0 0~255 Red Bias Adjustment (See Note 4 page 6.)

73 – 0 0 0~255 Green Bias Adjustment (See Note 4 page 6.)

– 0 0 0~255 Blue Bias Adjustment (See Note 4 page 6.)

— 6 —

SERVICE AD JUSTMENTS (Continued)

PROGRAM CODES

The microprossesor used in this model is a multi-purpose type and is used in several different models. To ensure proper operation and the correct features for your particular model, the Program Codes must be correct.

Note 1. Option Data 1 (NO. 57 OPT) should be decimal 88 (01011000 binary). See page 3 INITIAL DATA SETUP, step

20, for set up procedure. If this program code is wrong the TV will not operate properly.

Note 2. Option Data 2 (NO. 58 OP2) should be decimal 46 (00101110 binary). See page 3 INITIAL DATA SETUP, step

21, for set up procedure. If this program code is wrong the TV will not operate properly.

DRIVE / BIAS ADJUSTMENTS

Note 3. Red/Blue Drive Adjustments in Service Menu NO. 72 DRV: Adjust Red and Blue Drive Levels alternately with

1, 3, 7, and 9 keys on the remote control. (See Figure 2.) The Drive Level adjustment data will be written in the Service Menu No. 18 and 20 automatically.

4 5 6

7 98

RB(–)

RB(+)

BB(–)

BB(+)

(N/A)

GB(–)

(N/A)

GB(+)

(N/A)

FOR RED BIAS ADJUSTMENT

FOR BLUE BIAS ADJUSTMENT

FOR GREEN BIAS ADJUSTMENT

Figure 2.

Figure 3.

4 5 6

7 98

RD(–)

RD(+)

BD(–)

BD(+)

(N/A)

FOR RED DRIVE ADJUSTMENT

FOR BLUE DRIVE ADJUSTMENT

BIT FUNCTION

DATA

0 ~ 2 NOT USED — — 3 CLOCK NONE YES 4 COMB FILTER NONE YES 5 NOT USED — —

00: NONE

6, 7 SURROUND

01: YES 10: — 11: —

Note 4. Red/Green/Blue Bias Adjustments in Service Menu NO. 73: Adjust each Bias Level with 1, 3, 4, 6, 7, or 9 key on

the remote control. (See Figure 3.) The Bias Level adjustment data will be written in the Service Menu No. 15 ~ 17 automatically.

BIT FUNCTION

DATA

SHIPPING CONDITION

NORMAL COOL

OF COLOR ENHANCER 1 COLOR ENHANCER NONE YES 2 INITIAL CH & XDS NONE YES 3 AUDIO OUT & SP MENU NONE YES 4 PIP NONE YES 5 AV INPUTS 1 SET 2 SETS 6 BASS & TREBLE / TONE BASS & TR TONE 7 NOT USED

——

— 7 —

ANTENNA CONNECTIONS

This receiver is designed for UHF/VHF reception. A 75 ohm terminal is provided for UHF and VHF receptions. When connecting a CATV antenna system, connect the 75 ohm coaxial cable directly to the 75 ohm terminal. For 300 ohm VHF antenna, use an adapter (not included with the TV set).

CIRCUIT PROTECTION

Fuse F601 (4A) is included in the AC line. This fuse must be replaced with the proper fuse (see Parts List).

+B VOL T AGE CHECK

Connect Voltmeter + lead to TJ1 130V and – lead to ground (TE7). Connect receiver to AC 120V line. Tune receiver to an active channel. Reset the picture controls to the FACTORY PRESET levels (press remote control RESET key twice). Voltage must measure between +133.0V and +137.0V. If the voltage is out of this range, the power circuit must be checked. No +B adjustment is provided on this chassis.

HORIZONT AL WIDTH AD JUSTMENT

1. Tune receiver to an active channel.

2. Check the picture for proper width. If width is not correct, perform steps 3 ~ 6.

3. Turn off the receiver and disconnect the AC power cord (120V AC line).

4. While pressing the MENU key, reconnect the AC power cord. The Service Menu display will now appear.

5. Select NO. 47 EWD (EW DC) with ▲ or ▼ key.

6. Adjust the data with + or – key for proper width.To turn off the Service Menu display, press the MENU key.

HORIZONTAL CENTERING ADJUSTMENT

1. Tune receiver to an active channel.

2. Check that picture is in the horizontal center of TV screen. If picture is not centered horizontally, perform steps 3 ~ 6.

3. Turn off the receiver and disconnect the AC power cord.

4. While pressing the MENU key, reconnect the AC power cord. The Service Menu display will now appear.

5. Select NO. 03 HP (Horizontal Phase) with ▲ or ▼ key.

6. Adjust the data with + or – key for horizontal center. To turn off the Service Menu display, press the MENU key.

VERTICAL SIZE ADJUSTMENT

1. Tune receiver to an active channel.

2. Check the vertical size of the picture. If the vertical size is too large or small, perform steps 3 ~ 6.

3. Turn off the receiver and disconnect the AC power cord.

4. While pressing the MENU key, reconnect the AC power cord. The Service Menu display will now appear.

5. Select NO. 04 VS (Vertical Size) with ▲ or ▼ key.

6. Adjust the data with + or – key for full scan. To turn off the Service Menu display, press the MENU key.

VERTICAL CENTERING ADJUSTMENT

1. Tune receiver to an active channel.

2. Check that picture is in the center of TV screen. If picture center is too low, change resistor R513 from 1K ohm 1/2W to 470 ohm 1W. If picture center is too high, remove resistor R513 (1K ohm, 1/2W).

VCO AD JUSTMENT

Note: VCO must be adjusted after IC101 (Signal Processor),

IC802 (EEPROM) or T151 (VCO Coil) is replaced.

1. Tune receiver to an active channel.

2. Set the picture controls to the Sports level.

3. Connect digital voltmeter + lead to pin 58 of IC101 and – lead to ground (TE 7).

4. Confirm a reading of 3.6 ± 0.2 VDC.

5. If voltage is out of specifications adjust T151 for

3.6 ± 0.2 VDC.

RF AGC ADJUS TMENT

1. Tune receiver to strongest VHF station in your area.

2. Set contrast and brightness controls for maximum.

3. Turn off the receiver and disconnect the AC power cord (120V AC line).

4. While pressing the MENU key, reconnect the AC power cord. The Service Menu display will now appear.

5. Select NO. 42 RAD (RF AGC Delay) with ▲ or ▼ key.

6. Adjust the data with + or – key in the direction which causes snow to appear; then in the opposite direction until the snow just disappears.

7.To turn off the Service Menu display, press the MENU key.

VIDEO LEVEL

1. Connect color bar generator to antenna terminals.

2. Turn off the receiver and disconnect the AC power cord (AC 120V line).

3. Connect oscilloscope to TP16A (Q202 emitter) and ground.

4. While pressing the Menu key, reconnect the AC power cord. The Service Menu will now appear.

5. Select NO. 46 VL (Video Level) with the ▲ or ▼ key.

6. Adjust the + or – key for an oscilloscope reading of 1.0 ±

0.1 VP-P at TP16A. Press the MENU key to turn off the Service Menu display.

CAUTION

FOR CONTINUED PROTECTION AGAINST A RISK OF FIRE, REPLACE ONLY WITH THE SAME TYPE 4A, 125V FUSE.

ATTENTION : POUR MAINTENIR LA PROTECTION CONTRE LES RISQUES D’ INCENDIE UTILISER UN FUSIBLE DE RECHANGE DE MEME TYPE 4A, 125V.

1.0 ± 0.1 VP-P

Figure 4.

4A 125V

SERVICE AD JUSTMENTS (Continued)

— 8 —

GRA Y SCALE ADJUS TMENT

1. Set the picture controls to the Sports levels or Reset (use MENU key and ▲ or ▼ key or RESET key).

2. Turn off the receiver and disconnect the AC power cord (120V AC line).

3. While pressing the MENU key, reconnect the AC power cord. The Service Menu display will now appear.

4. Select NO. 15 RB (Red Bias), NO. 16 GB (Green Bias), and NO. 17 BB (Blue Bias) with ▲ or ▼ key and set each data to 0 with + or – key.

5. Select NO. 18 RD (Red Drive) and NO. 20 BD (Blue Drive) with ▲ or ▼ key and set each data to 64 with + or – key.

6. Set NO. 19 GD (Green Drive Reduction) data to 8, NO. 53 SB (Sub Brightness) data to 32, NO. 54 SCO (Sub Color) data to 7, NO. 55 STI (Sub Tint) to 20, and NO. 56 SSH (Sub Sharpness) data to 12 with ▲ or ▼, and + or – keys.

7. Turn Screen Control (T402) to minimum (fully counterclockwise).

8. Select the Service Menu NO. 73 (Bias Adjustments) with ▲ or ▼ key.

9. Advance Screen Control (T402) clockwise to obtain just visible one color line. If line does not appear, place this control to maximum (fully clockwise).

10. Raise each Bias Level with 3, 6, and 9 keys to obtain just visible white line. (See Figure 5.)

11. Select the Service Menu NO. 72 DRV (Drive Adjustments) with ▲ or ▼ key.

12. Adjust Red and Blue Drive Levels alternately with 1, 3, 7, or 9 key to produce normal black and white picture in highlight areas. (See Figure 6.)

13. Check for proper grayscale at all brightness levels. To turn off the Service Menu display, press the MENU key.

Note: If Grayscale Adjustment is made after picture tube

replacement, check Brightness Level Adjustment.

BRIGHTNESS LEVEL ADJUSTMENT

Note: Grayscale, RF AGC, Video Level, and High Voltage Check

must be adjusted before attempting Brightness Level Adjustment.

1. Connect a color-bar generator to the antenna terminals.

2. Switch the generator to the crosshatch pattern.

3. Reset the picture controls to the Sports levels.

4. Connect voltmeter (high impedance) + lead to terminal

TP51 and – lead to terminal TP50 on main board. Set

voltmeter for 1.5V ~ 3V range.

5. Turn off the receiver and disconnect the AC power cord.

6. While pressing the MENU key, reconnect the AC power cord. The Service Menu display will now appear.

7. Select NO. 53 SB (Sub Brightness) with ▲ or ▼ key.

8. Adjust the data with + or – key for 680 mVDC.

9. Press the MENU key to turn off the Service Menu display.

10. Check brightness level on every active channel, readjust (repeat steps 5 ~ 9), if necessary.

Note: Do not set to excessive brightness level, otherwise

the contrast level will be suppressed.

HIGH VOL T AGE HOLD-DOWN TEST

Every time the receiver is serviced, the HIGH VOLTAGE HOLD-DOWN circuit must be tested for proper operation by following these steps:

1. Connect receiver to 120V AC line. Tune receiver to active

channel. Reset the picture controls to the Sports levels.

2. Check that the voltage measured between TP7 and TE7

(ground side) is within 16.5 VDC to 21 VDC. If the voltage is out of this range, the Hold-Down Circuit must be checked.

3. Connect a DC Voltage supply to TP7 and TE7 through a

100 ohm 1/4W resistor. Adjust the DC voltage to 23 VDC. The receiver should shutdown, losing raster and sound. Then the receiver should turn off automatically. This reaction indicates that the Hold-Down circuit is functioning properly. If the receiver does not shutdown, a malfunction is indicated and its cause must be found and corrected.

4. To obtain picture again, remove the DC Supply and wait

a few minutes. Now turn on the receiver.

HIGH VOL T AGE CHECK

Note: +B (+130V) Voltage Check and Grayscale Adjustment

must be completed before attempting High Voltage Check.

1. Connect high voltage voltmeter – lead to ground, and

connect + lead to anode of picture tube.

2. Tune receiver to an active channel and confirm TV is

operating properly.

3. Eliminate the beam current by adjusting the contrast and

brightness controls to minimum.

4. Confirm high voltage is within 28.6 KV and 33.5 KV. If

reading is not within range, check horizontal circuit.

No high-voltage adjustment is provided on this chassis.

4 5 6

7 98

RB(–)

RB(+)

BB(–)

BB(+)

(N/A)

GB(–)

(N/A)

GB(+)

(N/A)

FOR RED BIAS ADJUSTMENT

FOR BLUE BIAS ADJUSTMENT

FOR GREEN BIAS ADJUSTMENT

Figure 5. Remote Control Number keys’ functions in

Service Menu NO. 73

4 5 6

7 98

RD(–)

RD(+)

BD(–)

BD(+)

(N/A)

Figure 6. Remote Control Number keys’ functions in

Service Menu NO. 72 DRV

FOR RED DRIVE ADJUSTMENT

FOR BLUE DRIVE ADJUSTMENT

— 9 —

FOCUS ADJUSTMENT

1. Connect a color-bar generator to the antenna terminals and select a crosshatch pattern.

2. Set the picture controls to the Sports levels.

3. Select a vertical line at the center of the screen and adjust the H focus control for best focus.

4. Select a horizontal line at the top of the screen and adjust the V focus control for best focus.

5. Repeat steps 3 and 4 for best focus.

SOUND ADJUSTMENT

1. Connect a color-bar generator to the antenna terminals with audio signal of 1KHz at 100% modulation.

2. Set the picture controls to the Sports levels

3. Connect oscilloscope + lead to TP21 (pin 75 of IC101) and – lead to ground.

4. Turn off the receiver and disconnect the AC power cord (AC 120V line).

5. While pressing the Menu key, reconnect the AC power cord. The Service Menu will now appear.

6. Select NO. 45 FL (FM Level) with the ▲ or ▼ key.

7. Adjust the data with the + or – key for an oscilloscope reading of 0.693 ± 10% VP-P at TP21.

8. Press the MENU key to turn off the Service Menu display and disconnect the oscilloscope from the chassis.

MULTI-SOUND SECTION ADJUSTMENTS

Note: Multi-Sound Section must be adjusted after

IC101 (Signal Processor), IC3401 (MTS Decoder), or IC802 (EEPROM) is replaced.

INPUT LEVEL ADJUSTMENT

1. Connect a signal to the antenna terminals with audio of 1 KHZ 100% modulation.

2. Turn off the receiver and disconnect the AC power cord (AC 120V line).

3. Connect voltmeter (RMS) to TP317 and ground.

4. While pressing the Menu key, reconnect the AC power cord. The Service Menu will now appear.

5. Select NO. 60 ATT (Attenuation) with the ▲ or ▼ key.

6. Adjust the + or – key for a voltmeter reading of 400 ± 20 mVrms at TP317.

SEP ARA TION AD JUSTMENT

7. Turn off the receiver and disconnect the AC power cord (AC 120V line).

8. Connect oscilloscope CH1 to TP317 and CH2 to TP318 and ground.

9. Connect an MTS TV/Stereo generator to antenna terminal.

10. While pressing the Menu key, reconnect the AC power cord. The Service Menu will now appear.

11. Select pilot, 300Hz audio frequency and Left modulating signal.

12. Select NO. 61 WDB (Wideband) with the ▲ or ▼ key.

13. Adjust the + or – key for minimum low frequencies at TP317. (See Figure 10.)

14. Select 4 KHz audio frequency and Right modulating signal.

15. Select NO. 62 SPC (Spectral) with the ▲ or ▼ key.

16. Adjust the + or – key for minimum high frequencies at TP318. (See Figure 10.)

Repeat adjustments (steps 11–16) until no further decreases in amplitude can be obtained. Press the MENU key to turn off the Service Menu display.

PURITY AND CONVERGENCE ADJUSTMENTS

Purity and Convergence have been aligned at the factory. No re-alignment is necessary.

Figure 10. Separation Adjustments

0.693 ± 10% VP-P

Figure 9.

Focus

Screen

Adjust the focus of this line using V focus control.

Adjust the focus of this line using H focus control.

Figure 7. Focus controls location

Figure 8. Focus adjustment

Minimize L leakage

TP317 (R)

300Hz

Minimize R leakage

TP318 (L)

4KHz

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