HITACHI 27CX31B Service Manual

27CX31 B 511

SERVICE MANUAL

27CX31

B 521

1 NTSC ] 1 GXCHASSIS 1

WC: CLU-418U2

CLU-411 ou

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

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

This television receiver will display television Closed Captioning (pi ) or ( I)) in accordance with paragraph 15.119 of the FCC rules)

TABLE OF CONTENTS

Introduction .................

Service Menu ................ 2

Factory Settings .............. 4

Servicing ..................

IF and Audio Alignment .......... 7

Purity & Convergence Procedure Remote Control

Component Parts List ...........

.............. 10

...... 8

13-l 8 Remote Schematic .............

Interconnect Diagram ............ 19

Main Module Schematics

Main Module S.M.D. Layout ........

Main Module Component Layout ......

PIP Module Schematic ........... 27

Jack Pack Schematic ............ 28

Keyboard Schematic ............ 29

Tuner Schematic ..............

.......... 20

SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT

25 26

SOLID STATE COLOR TELEVISION

JULY 1997 HHEA - MANUFACTURING DIVISION

PRODUCT SAFETY SERVICING GUIDELINES FOR AUDIO-VIDEO PRODUCTS

CAUTION: Do not attempt to modify this product in any way. Never perform customized installations without manufacturer’s approval. Unauthorized modifications will not only void the warranty, but may Iead to your being liable for any resulting property damage or user injury.

Service work should be performed only after you are thoroughly familiar with all of the following safety checks and servicing guidelines. To do otherwise increases the risk of potential hazards and injury to the user.

While servicing, use an isolation transformer for protection from AC line shock.

After the original service problem has been corrected, make a check of the following:

FIRE AND SHOCK HAZARD

Be sure that all components are positioned to avoid a possibility of adjacent component shorts. This is especially important on modules transported to and from the repair shop.

Never release a repair unless all protective devices such as insulators, harriers, covers, shields, strain reliefs, power supply cords, and other hardware have been reinstalled per the original design. Be sure that the safety purpose of the polarized line plug has not been defeated.

Soldering must be inspected to discover possible cold solder joints, solder splashes, or sharp solder points. Be certain to remove all loose foreign particles.

Check for physical evidence of damage or deterioration to parts and components, for frayed leads or damaged insulation (including the AC cord), and replace if necessary. Follow the original layout, lead length, and dress.

No lead or component should touch a receiving tube or a resistor rated at

1 watt or more. Lead tension around protruding metal surfaces must be avoided.

All critical components such as fuses, flameproof resistors, capacitors, etc. must be replaced with exact factory types. Do not use replacement components other than those specified or make unauthorized circuit modifications.

After reassembly of the set, always perform an AC leakage test on all exposed metallic parts of the cabinet (the channel selector knobs, antenna terminals, handle and screws) to be sure the set is safe to operate without danger of electrical shock. DO NOT USE A LINE ISOLATION TRANSFORMER DURING THIS TEST. Use an AC voltmeter having 5000 ohms per volt or more sensitivity in the following manner: Connect a 1500 ohm, 10 watt resistor, paralleled by a .15 mfd 15OV AC type capacitor between a known good earth ground (water pipe, conduit, etc.) and the exposed metallic parts, one at a time. Measure the AC voltage across the combination of 1500 ohm resistor and .15 mfd capacitor. Reverse the AC plug (if non-polarized) and repeat AC voltage measurements for each exposed metallic part. Voltage measured must not exceed 0.75 volts RMS. This corresponds to 0.5 milliamp AC. Any value exceeding this limit constitutes a potential shock hazard and must he corrected immediately.

GRAPHIC SYMBOLS

SAFETY CHECKS

A.C. Voltmeter

f, I

THE LIGHTNING FLASH WITH ARROWHEAD

SYMBOL WlTHIN AN EQUILATERAL TRIANGLE IS INTENDED TO ALERT THE SERVICE PERSONNEL TO THE PRESENCE OF NONINSULATED “DANGEROUS VOLTAGE” THAT

MAY BE OF SUFFICIENT MAGNITUDE TO CONSTTTUTE A RISK OF ELECTRIC SHOCK.

X-RADIATION

Be sum procedures and instructions to all service personnel cover the subject of x-radiation. The only potential source of x-rays in current TV receivers is the picture tube. However, this tube does not emit x-rays when the HV is at the factory-specified level. The proper value is also given in the applicable schematic. Operation at higher voltages may cause a failure of the picture tube or high voltage supply and, under certain circumstances, may produce radiation in excess of desirable levels.

Only factory-specified CRT anode connectors must be used. The degaussing shield also serves as an x-ray shield in color sets. Always m-install them.

It is essential that the service personnel have available an accurate and reliable high voltage meter. The calibration of the meter should he checked periodically against a reference standard, such as the one available at your distributor.

When the high-voltage circuitry is operating properly, there is no possibility of an x-radiation problem. Every time a color chassis is serviced, the brightness should be run up and down while monitoring the high voltage with a meter, to be certain that the high voltage does not exceed the specified value and that it is regulating correctly. We suggest that you and your service organization review test procedures so that voltage regulation is always checked as a standard servicing procedure, and that the high voltage reading be recorded on each customer’s invoice.

When troubleshooting and making test measurements in a product with a problem of excessively high voltage, avoid being unnecessarily close to the picture tube and the high voltage power supply. Do not operate the product longer than necessary to locate the cause of excessive voltage.

Refer to HV, B+, and shutdown adjustment procedures described in the

6. appropriate schematics and diagrams (where used).

IMPLOSION

1. All direct view picture tubes are equipped with an integral implosion protection system; take care to avoid damage during installation.

2. Use only the recommended factory replacement tubes.

TIPS ON PROPER INSTALLATION

Never install any receiver in a closed-in recess, cubbyhole, or closely fitting shelf space over, or close to, a heat duct, or in the path of heated air flow.

Avoid conditions of high humidity such as: outdoor patio installations where dew is a factor, near steam radiators where steam leakage is a factor, etc.

Avoid placement where draperies may obstruct rear venting. The customer should also avoid the use of decorative scarves or other coverings that might obstruct ventilation.

Wall- and shelf-mounted installations using a commercial mounting kit must follow the factory-approved mounting instructions. A product mounted to a shelf or platform must retain its original feet (or the equivalent thickness in spacers) to provide adequate air flow across the bottom. Bolts or screws used for fasteners must not touch any parts or wiring. Perform leakage tests on customized installations.

Caution customers against mounting a product on a sloping shelf or in a tilted position, unless the receiver is properly secured.

A product on a roll-about cart should be stable in its mounting to the cart. Caution the customer on the hazards of trying to roll a cart with small casters across thresholds or deep pile carpets.

Caution customers against using a cart or stand that has not been listed by Underwriters Laboratories, Inc. for use with its specific model of television receiver or generically approved for use with TVs of the same or larger screen size.

Caution customers against using extension cords. Explain that a forest of

8. extensions, sprouting from a single outlet, can lead to disastrous consequences to home and family.

THE EXCLAMATION POINT WITHIN AN

EQUILATERAL TRIANGLE IS INTENDED TO ALERT THE SERVICE PERSONNEL TO IMPORTANT SAFETY INFORMATION IN THE SERVICE LITERATURE.

GX CHASSIS

INTRODUCTION

The new GX series chassis has been developed for 27” screen size stereo models. Additional plug-in boards wil1 be adder the chassis to accommodate the different features: Stereo, Mono, PIP, etc.

The new GX series chassis features four 12C compatible ICs for all signal, sync and sweep processing. ICX2200 handles the audio/video, sync, and sweep drive processing. IC6000 is the microprocessor and IC6001 is the memory. The keybo; and IR detector are tied directly to IC6000. IC2100 handles the vertical sweep.

ICX3431 is in the power supply. This is a switching type supply powered by the bridge rectifier circuit. At turn on, volta for the vertical and video output circuit are derived from the sweep circuit.

rl to

all (

xd .ges

SERVICE MENU

A quick way to determine $-Factory Mode is “On” is if

a pair of dashes appears at the top of the Customer Setup Menu.

03 H Pos 44

I 1

Access the Service Menu by using either the remote control or the keyboard on the front of the set.

With Remote: Press and hold MENU until the User Menu display disappears, then press 9, 8,7,4, and ENTER, This will bring up the 03 HPos item of the Service Menu (see Figure 1).

With Keyboard: Press and hold MENU until the User Menu display disappears. Immediately press the Adj. Right and Channel Up keys simultaneously. To exit the Service Menu, press ENTER.

I I

Figure 1

Other unusual things to look for when Factory Mode is

“On” are, for example, the AC power-on feature is

always enabled regardless of the setting of “AC On” in the Service Menu. The set automatically turns on when AC is applied.

In addition, when Factory Mode is “On,” you can access the Service Menu by simultaneously pressing the Right Adj. and Channel Up buttons on the front of the set. Otherwise, you’ll have to use the remote to reenter the Service Menu to turn off Factory Mode.

Setup Menu

Auto Program Add/Del/Fav

Channel ID Clock Set

Timer Setup

Child Lock Captions Caption/Text Language

Auto Demo

Entry into and exit from the Service Menu will automatically unblock all child lock control.

See Figure 1. The black bar at the top indicates the part

number and version of the software in the set. The date on the left side of the black bar at the bottom indicates the date the module went through the factory. At the right is the date indicating when the module was tested.

The Service Menu will always come up on the third item H Pos. Use Select to toggle through all of the adjustments.

00 F MODE: (Factory Mode) Use Select to select item #OO, the first item in the Service Menu, in Factory Mode. This item is used by the factory when the modules are

being tested. In the field, this item should always be left

“Off.” Zero is “Off!” When Factory Mode is off, you’ll only be able to view

only the first seven items in the Service Menu. When Factory Mode is set to 1, you can view the 37 other menu

items. They will appear on the screen one at a time at the

top left of the screen. The black bars at the top and bottom

of the screen, as shown in Figure 1, will not appear.

Figure 2

You can also turn off Factory Mode by adjusting the setting of the clock or by running Auto Program in the customer Setup Menu.

01 Pre Px: Stores customer menu adjustments in the

nonvolatile memory of the EAROM. Settings for Contrast, Brightness, Color, Tint, and Color Temperature

are stored this way. 0 is custom and 1 is preset stored. 02 VPos: Moves on-screen display vertically. Range 0

to 31. 03 HPos: Moves on-screen display horizontally. Range 0

to 75. 04 LEVEL: Two settings: 0 and 1. 0 is private (Hitachi)

label 1 is other.

05 Band: Eight positions: 0 is broadcast fixed, 1 is

CATV aft search, 2 is HRC aft search, 3 is ICC aft

search, 4 is Broadcast aft search, 5 is CATV fixed, 6 is

HRC fixed, 7 is ICC fixed.

SERVICE MENU

06 AC On: Two positions: 0 is off and 1 is AC on. In the On position, the set will turn on when AC power is applied.

07 C Phas: (Caption Phase) Determines captioning phase. Range 0 to 254.

08 C Srch: (Caption Search) Range 0 to 1. 09 C Line: (Caption Line) Range 0 to 32.

10 RF Bpf: (RF bandpass Filter) Range 0 to 1.

113.58: 3.58 Mhz trap. Range 0 to 1. 12 RF Brt: (RF Brightness) Sets adjustment range of the

customer control for brightness in the RF mode. Range 0 to 63,

13 Ax Brt: (Aux Brightness) Sets adjustment range of the customer control for brightness in the AUX mode. Range 0to63.

14 MaxCon: (Max Contrast) Sets adjustment range of the customer control for contrast. Range 0 to 63.

15 V Phase: (Vertical Phase) Shifts picture vertically. Range 0 to 7.

16 HPhase: (Horizontal Phase) Shifts picture

horizontally. Range 0 to 3 1.

17 AudLvl: (Audio Level) Sets gain for the MTS Stereo.

Range 0 to 63.

18 AudAdj: (Sound Balance) Range 0 to 63. 19 RF AGC: Range from 0 to 63. 20 H AFC: Horizontal AFC 0= AFC 2 Normal,

l= AFC 2x3.

21 Wh Comp: (White Compression) Two settings: 0

and 1.

22 60 HzSw: (60 Hz Switched) O=Normal, l=H/V Locked, 2=Ideal, 3=V Locked, Range 0 to 3.

23 PifVco: (PIF Voltage Controlled Oscillator) Range 0

to 127.

24 R Cut (Red Cutoff) Range 0 to 254. 25 G Cut: (Green Cutoff) Range 0 to 254. 26 B Cut: (Blue Cutoff) Range 0 to 254. 27 G DVR: (Green gain) Range 0 to 254. 28 B DVR: (Blue gain) Range 0 to 254.

PIP Parameters 29 PIP Ras: (PIP Raster Register) Range 0 to 255. 30 PIP SW: (Pip switch delay) Centers PIP Border and

PIP picture in the Horizontal Direction. Range is 0 to 15. 31 PIP Lud: (PIP Luminance Delay) Matches Lum and

Chroma of the inset picture. Range 0 to 7.

32 PIPl: Range 0 to 127. 33 PIPX2: Range 0 to 127.

34 PIPYl: Range 0 to 127. 35 PIPY2: Range 0 to 127. 36 PIPTnt: Range 0 to 63.

Audio Parameters The following items are factory aligned. See Bar

Code label for correct settings. 37 Spectr: Range 0 to 15. 38 WideBa: (Stereo Voltage Controlled Oscillator)

Range 0 to 63.

39 SapVco: (Second Audio Program Voltage Controlled) Range 0 to 63.

40 SapLpf: (Second Audio Program Low Pass Filter)

Set to 0 (not adjustable). 41 StLpf: (Stereo Low Pass Filter) Set to 0 (not

adjustable). 42 Spectr: (High Frequency Separation) Set to 0 (not

adjustable). 43 WideBa: (Wide Band Low Frequency Separation)

Set to 0 (not adjustable).

Items 24 -28 are depending on the Color Temp setting in the Video Menu.

for B&W

tracking and change

FACTORY RECOMMENDED SETTINGS

GENERAL SETTINGS (Green)

ITEM 00 F Mode 01 Pre Px 02 v Pos 03 H Pos 04 Level 05 Band 06 AC On

07 C.Phas 08 C.Srch 09 C.Line

10RfBpf 11 3.58T 12 RF Brt

13 AxBrt 14 MaxCon 15 VPhase 16 HPhase 17 AudLvl 18 Aud Adj 19 RF Age

20 H Aft 21 Wh Comp 22 60HzSw 23 PifVco 24 R Cut 25 G Cut 26 B Cut 27 G Dvr 28 B Dvr

RANGE

;:: o- 31

0 - 75 ;:;

o- 1

0 - 254 : --32

O-l O-l 0 - 63 0 - 63 O-63 o-7 o- 31 0 - 63 0 - 63 0 - 63

;:: o-3

0- 127 0 - 254 0 - 254 0 - 254 0 - 254 0 - 254

TYPICAL SETTING

1 10

38 :

DESCRIPTION Factory mode 0 is Off 0 is Custom, 1 is preset

Moves the On-Screen Displays Vertically Moves the On-Screen Displays Horizontally

1 is other, 0 is P Lb1 (Hitachi)

Broadcast fixed

1 is On, 0 is Off

TECHNICAL SETTINGS (Black)

80 0

0 35

z: 0

ii; 35

; 46

4 ;0

Caption Phase 0 is Off, 1 is On Caption Line RF Bandpass Filter 1 is On, 0 is Off

3.58 Mhz Trap RF Sub brightness AUX Sub brightness Maximum Contrast Vertical Phase Horizontal Phase Sound Attenuation (Gain for LCS, MTS audio) Sound Balance RF AGC H Aft 0 is Off, 1 is On

White Compression 0 is Off, 1 is On

60 Hz Switch PIF Voltage Controlled Oscillator Red Cutoff Green Cutoff Blue Cutoff Green Gain Blue Gain

29 PipRas O-254

30 Pip SW o- 15

31 PipLuD o-7 32 PipXl 33 PipX2 0- 127 34 PipY 1 0- 127 35 PipY2 0- 127 36 PipTnt 0 - 63

37 InLev 38 StVco 39 SapVco 40 SapLpf 41 StLpf 42 Spectr 43 WideBa

0- 127

o- 15 0 - 63 o- 15 o- 15 0 - 63 0 - 63 0 - 63

PIP SETTINGS (White)

;

61 5 42

PIP Raster PIP Switch Delay PIP Luma Delay X position for PIP Left position X position for PIP Right position Y position for PIP Upper position Y position for PIP Lower position PIP tint adjust. This value allows the customer control to be centered for “neutral” tint.

AUDIO SETTINGS (Yellow)

Input Level Stereo VCO SAP VCO SAP LP Filter Stereo LP Filter Spectral High Freq. Separation Wide band Low Freq. Separation

SERVICING

POWER SUPPLY

Stand by Voltages +150 DC at RX3404 + 130 DC at CX3420 + 15 DC at emitter of Q3404 +5V DC at pin 3 of IC3442

Power On

Keyboard input at IC6000 pin 19 and 20 IR input at IC6000 pin 2 Power On output at IC6000 pin 52 Q3402 power supply switching transistor Switched Voltages

+9 volts DC at pin 3 of IC3441 +15 volts DC at collector of Q3404 Sweep Derived Voltages

+23 volts DC at the junction of CX3268 and RX3242 +35 volts DC at CX327 +-245 volts DC at junction of CX3296 and RX3217 CRT Filament at pins 1 and 2 connector 2F5

VIDEO PROCESSOR ICX2200

Key operating Signals Composite Video out to pin 41 Composite Audio out at pin 2 Horizontal Drive at pin 32 Vertical Drive at pin 24 Video output Blue at 2C5 pin 3 Video output Green at 2C5 pin 2 Video output Red at 2C5 pin 1 B+ 9 volts -pins 9,23,33,46 and 48

Serial Data, Serial Clock pins 30, 3 1

VERTICAL CIRCUIT Vertical drive pulse pin 3 +23 volts pins 2,10, and 11 Vertical out pin 1 Poor Linearity check C2114, C2115

HORIZONTAL CIRCUIT Horizontal drive to base of Q3202 predriver Driver transformer output base of Q3208

Shutdown voltage cathode D225 1

Scan derived voltages +23, +35 and +245 volts

SERVICE ADJUSTMENTS (Mechanical)

1. Vertical Size-R2133 Adjust R2133 for about l/2” overscan at top and bottom of picture.

2. Horizontal Width (Some Models) Adjust R3249 for l/2” overscan on both sides of the picture.

G2 ADJUST Use the following procedure when re-setting G-2:

Set brightness and contrast in the Video Menu to

mid-range.

Set color level to minimum, and tint to midrange.

Connect output of an NTSC generator to antenna input on receiver.

Select a color bar signal and turn color off. Adjust G2 control so that bar patterns range from completely black to a “not overdriven” (not saturated) white. There should be a distinct difference between black and white bars. Different shades of gray should be distinguishable if the G2 is set correctly.

Return the color level control to its normal setting. Leave generator connected if RGB cutoff is to be adjusted.

ADJUSTMENT OF RGB CUTOFF G2 control must be adjusted before RGB drive.

1. If main module or CRT has been replaced, select

default settings for drive and cutoff for RGB as listed in

Service Menu.

Set color level to minimum and tint to mid range.

Connect output of an NTSC generator to antenna input of receiver. Set generator to a white raster signals,

chroma off.

Enter Service Menu to gain access to cutoff adjustments. (Factory Mode item 00 must be set to 1 to

gain access to these adjustments).

Set items 24 R Cut, 25 G Cut, and 26 B Cut to 0. Set B and G DRV to the recommended settings (page 4 items

27 and 28).

Carefully observe which color is predominant on CRT. Do not adjust cutoff predominant color from 0 setting. Adjust other two cutoff controls for best white screen display.

Set generator to a color bar pattern and turn chroma off. Check that set displays a good gray scale from black to

white. If black level is too high, readjust G2 slightly.

Return the color level control to normal.

MICROPROCESSOR IC6000 IR in on pin 2

Power Ctl pin 52 +5 volts pins 22, 39 Clock Xtal pins 36, 37 Reset pin 35 H Sync pin 28, V Sync pin 29 R, G, B out pins 24,25,26

SERVICING

IMPORTANT

When replacing a main module, it should be checked for correct feature level of 0.

Change the feature by entering the Service Menu and selecting item 04 level. Use the adjust button to change the level.

HIGH VOLTAGE IS

NOT ADJUSTABLE

CRT Socket

45101

LIZ05

AUDIO

DETECTOR

VIDEO IC2200

KEYBOARD

CONNECTOR

II 2K6

[oi

MICRO IC6000

TUNER

Main Module

27V

VERTICAL

EAROM IC6001

FX3402

5A 2!5ov

LINE FX3401 4A 25ov

YOKE

t t

HORIZONTAL VERTICAL SIZE

WIDTH

FOCUS

SERVICING

IF AND AUDIO ALIGNMENT PROCEDURE

VIDEO DETECTOR If there is no viewable picture, enter Service Menu and

check default settings for the following items: Item 05 Band should be set to 0. Item 19 RFAgc should be set to 44. Item 23 PIFVco should be set to 48.

With a high impedance DC meter, measure VDC at pin 44 on ICX2200 or on R 12 19 with good standard signals such as off-air. Adjust item 23 PIFVco for VDC = 2SV+

This is also the AFC Crossoverpoint.

AGC DELAY With a strong noise-free antenna signal, adjust Service

Menu item 19 RFAgc setting lower until signal looks noisier, increase setting for a noise free picture.

you &just above setting 40, the tuner input will overload under certain conditions, causing other beats in the picture.

A more accurate method is to apply a channel 6 signal at 750~ V 75 ohms to the antenna. Then adjust Service Menu item 19 RF Age until tuner Age drops 1 VDC

from typical, Voltage can be measured at (+) terminal of capacitor C6028.

AUDIO DETECTOR If no audio is present, enter the Service menu and check

default setting for the following items: Item 17 AudLvl should be set to 44. Item 18 AudAdj should be set to 63. This item is not to

be field adjusted.

With a high impedance DC meter, measure VDC on

ICX2200 Pin 54 or (+) terminal of C 12 11 with a good standard signal such as off-air. Adjust L1205 for 4.0 VDC.

JACK PACK REMOVED

Attach a high impedance AC meter with a 47k load to pin 3 and ground lead to pin 4 of 4A9.

Ground pin 7 of 4A9.

Ground pin 2 of 4B9 through a 10k resistor.

Interrupt main AC power to reset microprocessor. Apply an RF signal with good video and audio at 400

5. Hz and 100% modulation.

Go to Service Menu item 17 AudLvl and adjust setting for 490 to 500 MVAC.

JACK PACK ATTACHED

1. Attach a high impedance AC meter to W1611 and ground lead to W 1603 on top of jackpack.

Ground

jumper W53 on main chassis to reduce high frequency

noise.

2. Interrupt main AC power to reset microprocessor.

3. Apply an RF signal with good video and audio at 400Hz and 100% modulation.

4. Go to Service Menu item 17 AudLvl and adjust setting for 490 to 500 MVAC.

MTS STEREO ALIGNMENT COEFFICIENTS

Enter coefficients (bar code data) attached to the jack pack at this item. Enter these settings in their appropriate

locations in the Service menu items 37 - 43 (starting with the left-most two digits for item 37).

-iWlCAl JACK PACK SAR CODE LABEL

LOCATED ON THE JACK PACK ASSEMBLY PCS

lllllnlllllllllilllmllnIllll

PCB Assembly

0 0 VARIABLE AUDIO RDM LEFT

37383940414243 -ServiceMenultam

1111111

29 03 09 26 30 30

ISYBC

-Serial Number

II J w

OUTPUT

-label is located on the back

The above Audio Bar Code side of PCB Assembly,

along the edge

/’

STEREO LEVEL ADJUST This adjustment c& be made with jack pack removed or

attached to the chassis. Service menu item 17 AudLvl should not be changed

unless ICX2200 has been replaced on the main chassis. If an MTS jack pack is changed, the new coefficients

(bar code data) must be entered in the Service menu for

proper stereo alignment.

YEP

SERVICING

PURITY & CONVERGENCE SET-UP PROCEDURE FOR COTY CRTs

PRELIMINARY SET-UP

1. Allow the receiver to warm up for 15 to 20 minutes.

2. Degauss the receiver.

3. Connect a crosshatch generator to the receiver and “rough in” the static (center) convergence. Follow the

Convergence Procedure.

4. Adjust for best focus.

PURITY ADJUSTMENT

1. Purity tab positioning: Set the 2 pole purity tabs together in the 3 or

9 o’clock positions and the 4 and 6 pole purity tabs

together in the 12 or 6 o’clock positions.

2. Move yoke to the maximum forward funnel position.

3. Switch the crosshatch generator to a red field.

4. Pull the yoke toward the rear of the CRT neck until the centered pure red raster is displayed,

5. If the red raster is not displayed as a pure red field, adjust the 2 pole purity tabs until a pure field is obtained.

6, Check for proper yoke tilt setting.

CONVERGENCE ADJUSTMENT

1. Release locking assembly,

2. Connect crosshatch generator to the receiver and adjust static (center) convergence as follows:

a. Adjust the 4 pole static control by moving the

two tabs separately to converge the red and blue lines horizontally. Move the two tabs together around the neck of the CRT (in a 45’ arc) from the top dead center position to converge the red and blue lines vertically.

b. After the 4 pole control has been adjusted to

superimpose the red and blue lines on top of

one another, use the 6 pole static adjustment to place the converged red and blue lines over the green line. Move the two tabs together around the neck of the CRT (in a 30’ arc) from the top dead center position to move the lines vertically. Adjusting the two tabs separately will move the converged beam to the left or right. Using a crosshatch generator capable of producing individual fields, adjust generator to produce a red field. Use the purity tabs to center a red stripe.

PURITY &CONVERGENCE

CRT Ring Location Purity

Adjust Tabs Beam Movement for Convergence

Ring Pairs

6 Pole

Rotation direction Movement of Red

of both tabs and Blue beams

Opposite

43 (9

+ 23 hidden pages