Commodore 1802 User manual

Commodore Deutschland
Kramer
COMMODORE
1802
COLOR MONITOR
Technical Manual
5/87

Materials
for
1802
Manual
o
NISC
aC:
120V
60Hz
0.8A
60¥
o
PAL
AC
:
220V
S0Hz
604
o
Features
(compared
vith
1702)
1)
Additional
Switches
:
Video,
Audio
I
&
II,
Monochrome
2)
40-column
Monitor
:
40
characters
x
25
lines
(8
x
8
dots)
3)
3-mode
Video
Select
Switch:
1.
Composite
---
For
VIR,
TV
tuner,
home
computer,
etc.
2.
Separate
---
For
C64,
C128
and
TED
series
3.
Monochrome
---
For
home
business
computer
(Green
screen
display
to
protect
eyes)
The
figure
below
is
an
example
of
connecting
a
three-jack
cable
to
the
rear
panel.
Monitor's
Rear
Panel
a) sparate Mode:
Commodore
Personal
Computer
b) Composite Mode:
Connect
the
cable
to
VIDEO
and
AUDIO
I,
c) Monochrome Mode:
Connect
the
cable
to
MONOCHROME
and
AUDIO
ITI.
The
jack
end
of
the
cable
can
be
plugged
into
the
CHROM
socket
in
any
mode.
NOTE:
Mode
is
selected
with
the
3-mode
Video
Select
Switch
on
the
front
control
panel.

Q)
POWER
INDICATOR
|
ase
“@
PovER
BUTTON
===SSS=*~*~<—*~*s*C*<~*‘«~«t
NSS
“@
FRONT
CONTROL
PANEL
SSC~sYSC(‘~*S
=
~—
@
voz
=—=——SS*S*S*S*«@:C«é
nad
contro
kno
~—
@
VIMEO
MODE
SWITCH
—~—~*|
_‘S-position
slide
svitch
“Gti
Sm
Mama
ponteel
each
iO
re
eee
em
~
@conmesst.——=—~—~—~S*S*S*«~Y:~S*~*«
anual
control
nob
~
@
seer
=
———~S~S*S*~S*S*«*SS~S*«Ranua
contro
knc
@vVwis
=
—~—~—~—~~—~—~—S«SY~Ss«CManual
control
knob
~~
@
wrest
——~—~—~S~S*~S™S”*WYS«CManad
control
knob
-
(G)
ab,
SSS
CG
Maneal
conteol
knob:
@mern
=
t™~—“—sCSsSC“<i=‘“<s
SS
VIDEO
(YELLOW)
=SS*~*~*~d=CS*~S*«sip
ace
"aUDIO
1
(WHITE)
=—SSS*~*~*~«~wS*~CS*~CS«és
Gack
UNA
(ELLOW).=SSSS*~*~*~*dS*SCS*«<CS~Ssip
Sak
"CHROMA
(RED)
==SSS*~*<“<~*é‘“*!:*S*sp
Sack
SS
"AUDIO
TE
(WHITE),
=——=S*~*~*~S*dYSCS*é*<CS~sip
ake
SS
"MONOCHROME
(VELLOW)=—==S=S*=*d*S*S*«sip
eck
@uuumzSt~—<—S~sSC“‘<‘<‘<C
@
warranty
(woo)
sst—<~iS*ti<CS*é~S
a
@
Ram
useStC<is~—S*S~CS~S
—
@
powrcop
|
=e
NOTES: (@) V-HEIG = VERTICAL HEIGHT
(0) H-POSI = HORIZONTAL POSITION
(1) V-HOLD = VERTICAL HOLD

pecgeenetea
@
VIDEO
MODE
SWITCH
COLOR
MONO
COMP
SEP
eanaua
Co.)
I
«
Iit
@_REAR
PANEL
I
©
.
It
©
LUMA
CHROMA
AUDIO
II
IIl
©
MONO
CHROME
STUN
Wu
WVU
veal
nett. SS
@
FRONT
CONTROL
PANEL
ee
eee

CONTENTS
SPECIFICATIONS
,
oan
1
IMPORTANT
SERVICE
SAFETY
INFORMATION
2
INSTALLATION
AND
CHASSIS
PARTS
LOCATION
3
SERVICE
INSTRUCTIONS
5
SERVICE
ADJUSTMENT
12
SERVICE
INFORMATION
19
Rear
Connection
Panel
19
PC.B
Board
Layouts
19
Circuit
Diagram
23
Block
Diagram
24
Parts
List
25
SPECIFICATIONS
SSS
Ae
SS
a
a
a
Ee
CRT:
13V
inch
90’
in-line,
Vertical
Stripe
Video
band
width:
Composite;
3.5MHz
Phosphor
0.62mm
pitch,
gray
face.
Seprated
video
(luma
&
Chroma);
input
Signals:
PAL
Composite,
Separated
4.2
MHz
Mono
video,
4.2
MHz
video
(luma
&
chroma),
Scanning
frequency:
Horizontal;
15.625
KHz
Monochrome
video,
Audio
|,
Vertical;
50 Hz
Audio
II.
Audio:
Input;
1Vpp/47K
Input level
Comp.,
Video,
Output;
1W
OMA;
Mono;
WWp.p/75_
Sd
Dimensions:
356(W)
x
380(D)
x
391(H)
mm
Display
size:
247(H)
xX
160(V)
mm
Weight:
Approx.
12
Kg
Colors:
Comp.; Full
colors
Power
input:
220 VAC,
50
Hz
Resolution:
Comp.;
1,000
characters
Power consumption:
65W
(40
column
x25
lines)
plat
ad
Stele
hl
lc
a
a,
*Design,
features
and
specifications
are
subject
to
change
without
notice.

IMPORTANT SERVICE SAFETY INFORMATION
WARNING:
An isolation transformer must be used between the AC supply and the AC plug of the color monitor before servicing or testing
is performed on this monitor, since part of the chassis and the heat-sink are directly connected to one side of the AC line which
could present a shock hazard. The chassis of the monitor should never be connected ground.
Before servicing is performed, read all the precautions labelled on the CRT, chassis, and on the inside of the cabinet of this monitor.
X-RAY RADIATION WARNING NOTICE
WARNING: PARTS WHICH INFLUENCE X-RAY RADIATION IN HORIZONTAL DEFLECTION. HIGH VOLTAGE CIRCUITS
AND PICTURE TUBE, ETC., ARE INDICATED BY (x) IN THE PARTS LIST FOR REPLACEMENT PURPOSES. USE ONLY
THE TYPE SHOWN IN THE PARTS LIST.
PRODUCT SAFETY NOTICE
WARNING: FOR CONTINUED SAFETY, REPLACE SAFETY CRITICAL COMPONENTS ONLY WITH MANUFACTURER
RECOMMENDED PARTS. THESE PARTS ARE IDENTIFIED BY SHADING AND BY (A\) ON THE SCEMATIC DIAGRAM.
RRR
NOTICE D’AVERTISSEMENT DE RADIATION AUX RAYONS X
AVERTISSEMENT: LES PIECES QUI INFLUENCENT LES RAYONS X AU COURS DE LA DEVIATION HORIZONTALE, LES |
CIRCUITS A HAUTE TENSION ET LE TUBE-IMAGE, ETC. SONT ACCOMPAGNEES D’UN ASTERIQUE( *) DANS LE
CATALOGUE DE PIECES DETACHEES. DANS LE CAS D’UN REMPLACEMENT, UTILISER UNIQUEMENT LES MODELES
DE PIECES INDIQUES DANS LE CATALOGUE DE PIECES DETACHEES.
NOTICE DE SECURITE
AVERTISSEMENT: POUR ETRE ASSURE D'UNE SEOURI OPTIMENT A TOUT MOMENT, REMPLACER LES COM-
POSANTS CRITIQUES UNIQUEMENT PAR LES PIECES RECOMMANDEES PAR LE FABRICANT DE LAPPAREIL, CES
PIECES SONT IDENTIFIEES PAR UNE ZONE D'OMBRE FT PAR LE SYMBOLE (4\) SUR LE SCHEMA DE MONTAGE.
The manufacturer's warranty and liabilities will be void if any unauthorized modifications, alterations or additions are made.
For replacement purposes, use the same type or specified type of wire and cable, ensuring that the positioning of the wires
is followed (especially for HV. and power supply circuits). Use of alternative wiring or positioning could result in damage to the
set or in a shock or fire hazard.
The picture tube used in this monitor employs integral implosion protection and should be replaced with the tube of the same
type number for continued safety.
When handling the CRT, shatter-proof goggles must be worn after completely discharging the high voltage circuit.
Do not lift the picture tube by the neck.
eee PRECAUTION
. Potentials as high as 24,000 volt!s are present when the monitor is operating. Operation of the monitor ourside the cabinet
or with the back board removed involes a shock hazard from the monitor.
2. Servicing should not be attempted by anyone who is not thoroughly famillar with the precautions necessary when working
on high-voltage equipment.
. Always discharge the picture tube to the monitor chassis to keep off the shock hazard before removing the anode cap.
. Perfectly discharge the high potential of the picture tube before handling the tube. The picture tube is highly evacuated and
if broken, glass fragments will be violently expelled.
. lf any FUSE in this monitor is blown, replace it with FUSE specified in the chassis parts list.
. When replacing a high wattage resistor (oxide metal film resistor) in circuit board, keep the resistor 10mm away from circuit board.
. Keep wires away from high voltage or high temperature components.
. This monitor must operate under AC220 volts, 50Hz, NEVER connect to DC supply or any other power or frequency.
ho
OND MO

INSTALLATION
AND
CHASSIS
PARTS
LOCATION
INSTALLATION OF THIS COLOR MONITOR CHASSIS AND INITIAL CHECK POINTS
When
installing
this
color
monitor
chassis,
first
check
operation
on
a
black
and
white
telecast.
Check
and
if
necessary,
adjust
centering,
size,
and
focus.
Observe
the
picture
for
proper
black
and
white
reproduction
(tracking)
over
all
areas
of
the
screen.
No
objectionable
color
shading
or
fringing
should
be
evident.
If
shading
or
fringing
is
evident,
degauss
the
monitor.
In most instances after installation, a technician need only degauss the faceplate area and touch-up the static (center) con-
vergence.
CHASSIS PARTS LOCATION
The
degaussing
coil
should
be
moved
slowly
around
the
front
faceplate
of
the
picture
tube
and
around
the
sides
and
front
of
the
monitor.
The
coil
should
then be
withdrawn
slowly
to
a
distance
of
at
least
six
to
ten
feet
before
disconnecting
from
the
AC
supply.
This monitor chassis is equipped with an automatic degaussing circuit which effectively demagnetizes the faceplate each
time the monitor is switched ON after having been OFF for at least ten minutes.
Note:
See ‘SERVICE ADJUSTMENT’ on page 12 for details of adjusting procedures.
Focus ADJ.
Screen ADJ.
SIGNAL INPUT
PANEL
CONTRAST
BRIGHT
N
4
2nd
ANODE
CAP
COLOR
MODE SELECT SW.
VOUUME CRT SOCKET
AC POWER CORD
Fig. 1

sw701 Color Bright Contrast
1601 R509 R233 R220
Input signal DELAY LINE R997
DM . DLS501 Sub Bright
ces) CHROHA
AMPLITUDE
R507 R409
:
H.
HOLD
.
[5]
t02
a
4PC
Adj
[0]
|
1301
——
EM R309
R522
ess) COLOR SYNC Q402
R418 C417
C426
R411
Pin
) V-CENTER creer
“R359
___| TSW-4204
01 T801 L» Focus Adj
Screen Adj
Nonisolation
Isolation
Ree
(CM-146 MAIN BOARD)
R565 R BIAS
R572 G BIAS
R578 B BIAS
R446 R DRIVE
R580 B DRIVE
NECK BOARD

SERVICE INSTRUCTIONS
a
hon
_
CHASSIS REMOVAL (SEE FIGS. 3/4)
. Remove the five screws securing the rear cover of the
cabinet. (See Fig. 3)
. Pull the rear cabinet about 10cm to the rear.
. Remove the rear cabinet.
. Remove solder connection of the black wire connecting CRT
grounding and neck pc board, then remove the neck p.c
board from the picture tube. (See Fig. 5)
. Remove the second anode cap.
Remove five Screws
Fig. 3
MAIN CHASSIS SERVICING
Remove the rear cabinet.
. Repairing of main chassis can be done easily, if stood as
shown in Fig. 6.
O ON
. Remove the connectors as follows:
1) Deflection yoke connector
2) Degaussing coil connector
3) Speaker connector
. Remove the two screws securing the power switch.
. Take the chassis out of the cabinet.
. To install the chassis, repeat the above procedure in reverse
order.
Remove Second Anode Cap
Remove Solder Connection of
Black Wire from CRT Ground
Fig. 5

PICTURE
TUBE
REMOVAL
gash
In order to remove or replace the picture tube, the chassis
must first be removed. Refer to Chassis Removal procedure.
After the chassis has been removed, proceed as follows.
1. Loosen the clamping screws on the deflection yoke, purity
and static convergence magnet, and remove them.
2. Remove four screws securing the picture tube to the front
cabinet.
PRECAUTIONS FOR REPAIRS
1. Check for bad contacts on connectors on the main PC board
and elsewhere by applying hand pressure.
2. Check AC power supply for problems-e.g. blown fuse, bad
switch or AC outlet.
3. Check for intermittents or defective soldering on the main
board by striking the reverse side of the board gently with
an insulated bar.
4. When soldering PC boards, limit the soldering iron
temperature to 500°F (200°C) to avoid peeling of the foil.
5. When soldering transistors or other semiconductors, use
tweezers or a heat sink clip as shown in Fig. 8 to prevent Soldering iron
heat
damage.
Shr
(20
thru
40W)

TROUBLESHOOTING
“+
As
major
parts
of
this
chassis
employ
!Cs,
defects
can
often
be
isolated
by
referring
to
the
table
of
symptoms
in
Table
1.
Additional
checks
of
transistor
and
IC
DC
voltages
and
waveforms
as
shown
on
the
schematic
will
assist
in
pinpointing
the
pro-
blem area. Remember
also
to
check
for
faulty
resistors
and
capacitors,
etc.
around
defective
ICs
and transistors.
Table 1 IC/TR Failure and Symptoms
IC/TR SYMPTOM
Video Chroma Circuit Composite/Separate/Monochrome-mode reception
No picture and poor picture.
No color and monochrome.
Poor color synchronization.
Hue discrepancy.
Vert./Horiz. osc., Vertical line only.
Drive/Sync. sep. No picture, No high voltage.
circuit Unstable picture.
1301: Vert. output circuit Horizontal line only.
Poor vertical scan.
1801: $.M.PS. circuit No. power (No Lamp)
high voltage, fuse is blown.
Dark or brighter picture.
No green picture.
Green with retrace line picture. _
No red picture.
Red with retrace line picture.
Q553: Blue output circuit No blue picture.
Blue with retrace line picture.
Q202: ABL circuit
Q552: Green output circuit
1701: Video interface circuit No picture or poor picture.
switch. Incorrect color.
1601: Audio amp. circuit No sound or poor sound
Q001, Q003, Video amp. circuit Composite/Separate mode/Mono
Q005, Q007 No picture or poor picture.
Q701: 4.43MHz trap. circuit Composite mode
Smail dotted stripes appear in the picture.
Q203: Video drive output circuit Composite/Separate mode/Mono
No video or poor video
Q702: Chroma amp. circuit Separate mode
No color or incorrect color.
Q401: Horiz. drive circuit No picture
Does not generate high voltage.
Q402: Horiz. output circuit No picture, does not generate
Q551: Red output circuit
NJ

TROUBLESHOOTING
CHARTS
aes
The following charts are devoted to troubleshooting which, if followed carefully, will assist you in tracking down a fault to
the collect stage. In order to utilize the charts (fault trees), firstly establish the complaint, ie. no raster.
Locate the chart applicable and then progress through the various alternatives until a final block the offending components
or stage.
1. NO RASTER
CHECK MAIN B+ (123V) ON MAIN PCB.
Normal Abnormal
CHECK 16.5V LINE OF FBT
CHECK F801 (Fuse)
CHECK/REPLACE Normal Abnormal
POWER CIRCUIT
HORIZ. CIRCUIT i y
CHECK
+12V LINE
REPLACE F801
CHECK/REPLACE
R402, D404
CHECK D801, D802 NG| REPLACE D801
D808, D809, ; D802, D808, CHECK/REPLACE STILL
R801 D809, R801 HORIZONTAL -+ NO RASTER
CIRCUIT OF
NORMAL | 1201 (TA 7698)
CHECK 1801, REPLACE 1801,
v
ABNORMAL
RASTER
APPEARS
Q805, Q806 Q805, Q806
REPLACE D806,
T801
CHECK D806,
T805
aR
CHECK/REPLACE
24V LINE (R322, D303)
185V LINE (R420, D403)
OF FBT.
CHECK
HORIZONTAL OUTPUT
CIRCUIT

2. NO SOUND
CHECK/REPLACE
D807, R830
OK +13.5V
STILL NO SOUND
3. NO PICTURE
CHECK/REPLACE
MODE OF INPUT STAGES:
VIDEO POCESSING PART OF
Q001, Q003, Q004, Q005, Q007
Q201, 1601
ABNORMAL
EACH SIGNAL (COMP, SEP, MONO)
CHECK SOUND B+ (13.5V) ON MAIN PCB
NORMAL
CHECK 1601
PIN 1 (13.5V)
PIN 10
CHECK WHETHER THE BRIGHTNESS IS CONTROLLABLE OR NOT
CHECK+ 185V LINE
ON THE CRT DRIVE
OK
STILL NO PICTURE
CHECK/REPLACE
THE EACH PIN OF 1601
(COMP, SEP, MONO MODE)
CHECK/REPLACE
THE SIGNAL INPUT
CIRCUIT & BOARD
(Q001, Q003, Q004,
Q005, Q007, 1201)
(SOUND WAVEFORM)
CHECK/REPLACE
RECTIFIR CIRCUIT
R420, D403, C420,
REPLACE
1601
(KTA7208)

4. NO COLOR (FOR COMP. & SEP MODE)
READJUST R552 ON MAIN PCB.
NO
COLOR
NORMAL
CHECK
THE
VOLTAGE
OF
CHECK/REPLACE
R552
EACH
PIN
OF
1201
NORMAL
ABNORMAL
SHORT BETWEEN PIN 39 REPLACE 1201
AND PIN 5 OF 1201
BY 0.01zF CAPACITOR
ABNORMAL NORMAL
CHECK/REPLACE CHECK/REPLACE THE
X501,
L552
CHROMA
INPUT
CIRCUIT
5. SPECIFIC TINTED COLOR
CHECK THE VOLTAGE OF 1501 (PIN 20, 21, 22)
NORMAL ABNORMAL
ADJUST L552 CHECK/REPLACE JC501, CHROMA
(PHASE
CONTROL)
CIRCUIT
OF
1201
STILL SPECIFIC COLOR STILL
ABNORMAL
CHECK/
REPLACE
L552,
eincUn
Geet
Geez
cee
PAL
DELAY
LINE
CIRCUIT
(R551, L551)
10

6. NO VERTICAL SCAN (ONE HORIZ. LINE RASTER)
CHECK/REPLACE R326
OPEN
CHECK/REPLACE THE VERTICAL
OUTPUT CIRCUIT
REPLACE R326
NORMAL
CHECK/REPLACE VERTICAL OUTPUT
CIRCUIT
(MEASURE THE VOLTAGE OF +24V
LINE)
CHECK THE VOLTAGE OF EACH
PIN OF 1301
ABNORMAL
REPLACE 1301
NORMAL
CHECK/REPLACE DEFLECTION
YOKE AND CONNECTION
7. OUT OF VERTICAL SYNC. AND HORIZ. SYNC.
CHECK/REPLACE
SYNC.
SEPARATION
CIRCUIT
AND
1201
8.
OUT
OF
VERTICAL
SYNC.
9.
OUT
OF
HOIRZ.
SYNC.
CHECK/REPLACE
VERTICAL
OSC.
PART
OF
1201
9. OUT OF HORIZ. SYNC.
CHECK/REPLACE
HORIZ
OSC.
PART
OF
1201,
AFC
CIPCUIT
1

DESOLDERING OF ICS AND TR
The following tools are suggested for desoldering semicon-
ductors:
1. Desoldering tools
a) Hand suction type-Solda-Pullt® (model SS011, Edsyn inc.
Van Nuys, CA.) or equivalent.
b) Wire-Wick type-Solder-Wicle® (size=4, Solder Removal
Co., Covina, CA) or equivalent.
Desoldering
Fibbon
2. Soldering !ron-Maximum wattage recommended is 40W.
Higher power soldering irons may damage the copper foil
of board.
Note:
When desoldering parts, heat the joint and remove the solder
quickly. The PC foil may peel from the board if heat is applied
for too long.
SERVICE ADJUSTMENT
FOCUS ADJUSTMENT
Adjust the focus control, located on the H.V. unit (1461) for
maximum overall definition and fine picture detail with
brightness and contrast controls set at normal viewing levels.
VERTICAL SIZE (R901) ADJUSTMENT
The vertical size (height) control is the screwdriver adjust-
ment that is accessible through the front cover.
Location of the control is shown in Figs. 1 and 10.
These controls must be adjusted until the correct picture or
test pattern is obtained.
12
CIRCUIT PROTECTION
4.0A fuse, mounted on the main PC board, has been provid-
ed to protect the power out put circuit. See Figs. 2 and 10.
HORIZONTAL HOLD (R409) ADJUSTMENT
(SEE FIGS. 1 AND 10)
Receive the color signal.
Set the brightness and contrast controls to a normal position.
A warm-up period of at least five minutes should be allowed
and alignment should be done.
1. Connect a capacitor (2uF/50V) between pin 37 of 1201 and
Ground.
2. Adjust the horiz. hold control (R409) until the picture is stable.
(Tune R409 to 15.625KHz). After adjustment, remove the
capacitor.

a
mR
A
a
Ne)
ad
OD
APC ADJUSTMENT (SEE FIG. 10)
This adjustment should be made only when the
chroma/video IC (!201) or parts of the APC circuit have been
replaced, or when the picture colors are unstable. For adjust-
ment, use the APC ADJ. control (1501).
Procedures
1.
N
oo hw
Apply a colour bar signal to the video input terminal Turn
the colour control fully clockwise and position the
Brightness, controls at mechanical center.
. Cut off the colour killer by connection of Pin 2 and Pin 12
of IC501 with 10k ohm resistor. (Set the contrast, brightness,
colour controls to maximum)
. Short L552 to ground with a jumper Wire.
. Adjust R552 so that the colour bar pattem stands still or
drifts slowly across the picture screen.
. After adjustment, remove the jumper wire and resistor.
. Check that the colour sync is stable with channel chang-
ing and power on-off operation. If the colour is slow to ap-
pear or the colour sync is out of order, retouch the colour
sync R552 for proper colour display.
os OoOnm-
COLOR AMPLITUDE AND PHASE
ADJUSTMENT
. Receive PAL/DEM-bar signal.
. Connect the probe of oscilloscope to BY output.
. Adjust L552 and R551 in order to make wave form flat on
screen.
. Receiver color bar signal instead of DEM signal.
. Adjust L551 to make BY output stable.
VERTICAL POSITION CONTROL (R359)
ADJUSTMENT (SEE FIG. 10)
The vertical position contro! (R359) is the VR which controls
the vertical position of the picture. If the vertical position of
the picture is not at the center of the pciture tube, adjust the
vertical position by turning this control.
13

Color Britht Contrast
R509 R233 R220
Sw701
DELAY LINE rzor (>)
Input signal
1701 © Bright
PM 3 DL501 a
: T501
Rowe R409
=
seen
1201
<e5)
H.
HOLD
BM
T502
[0
|
amputuve
<5 V. Linearity
|
1301
R309
ee ae COLOR
SYNC @” fais Q402
R522 C417
C426
R418
R411
Pin
V-CENTER Cushion
R359 Ba
rer L_
C812
L_--| TSW-4204 |__ |
1801 7801 1 C813 L» Focus Adj
t
t
& o s
< ie) x
m
Screen Adj
ee ee
Nonisolation
Isolation
CM-146 Main Board
Fig. 10
VERTICAL LINEARITY CONTROL (R309)
ADJUSTING (SEE FIG. 10)
The vertical linearity control (R309) is the VR which controls the vertical linearity of the picture.
After received cross hatch pattern, adjust -the vertical linearity by turning this control.
14

SUB BRIGHTNESS (R223)
This control is adjusted at the factory.
When readjustment is required, proceed as follows:
1. Receive H characters pattern at SEP mode.
2. Set the contrast and brightness controls at the mechanical minimum position.
3. Adjust the sub brightness control so that back ground of the picture is just disappeared..
COLOR PURITY ADJUSTMENT
For best results, it is recommended that the purity adjustment be made in the final location. If the monitor will be moved,
perform this adjustment with it facing east or west. The monitor must have been operating 15 minutes prior to this procedure
and the faceplate of the CRT must be at room temperature.
The monitor is equipped with an automatic degaussing circuit. However, if the CRT shadow mask has become excessively magnetiz-
ed, it may be necessary to degauss it with a manual coil. Do not switch the coil OFF while the raster shows any effect from the coil.
Purity magnets are used for color purity and vert. centering adjustment.
Purity adjustment procedure is as follows.
NOTE:
Before attempting any purity adjustments, the receiver should be operated for at least 15 minutes.
1. Demagnetize the picture tube and cabinet using a degaussing coil.
2. Turn the CONTRAST and BRIGHTNESS controls to maximum.
3. Adjust RED and BLUE Bias controls (R554 and R564) to provide only a green raster. Advance the GREEN BIAS control (R559)
if necessary. :
4. Loosen the clamp screw holding the yoke, and slide the yoke backward to provide vertical green belt (zone) in the picture screen.
5. Remove the Rubber Wedges.
6. Rotate and spread the tabs of the purity magnet (See Fig. 7) around the neck of the picture tube until the green belt is
in the center of the screen. At the same time, center the raster vertically.
7. Move the yoke slowly forward until a uniform green screen is obtained.
Tighten the clamp screw of the yoke temporarily.
8. Check the purity of the red and blue raster by adjusting the BIAS controls.
9. Obtain a white raster, referring to “Black and white tracking”
10. Proceed with convergence adjustment.
15

STATIC
CONVERGENCE
ADJUSTMENT
ae
A recently developed deflection yoke and electron guns construction has been used on this equipment in combination with
in-line guns and black stripe screen to make a barrel-type magnetic-field distribution for vertical deflection and pin-cushion-type
magnetic field for horizontal deflection with which a self-converging system can be obtained. this type is different from conven-
tional unity magnetic field distribution type deflection yoke. 4-pole magnets and 6-pole magnets are employed for static con-
vergence instead of a convergence yoke.
1. A crosshatch signal should be connected to the video input terminal of the monitor.
2. Adjust the BRIGHTNESS and CONTRAST Controls for well defined pattern.
3. Adjust two tabs of the 4-pole Magnets to change the angle between them (See Fig. 11) and superimpose red and blue vertical
lines in the center area of the picture screen. (See Fig. 12 )
4. Turn both tabs at the same time keeping their angles constant to superimpose red and blue horizontal lines at the center
of the screen. (See Fig. 12)
5. Adjust two tabs of 60-pole Magnets to superimpose red/blue line with green one. Adjusting the angle affects the vertical
lines and rotating both magnets affects the horizontal lines.
6. Repeat adjustments 3, 4, 5, keeping in mind red, green and blue movement, because 4-pole Magnets and 6-pole Magnets
interact and make dot movement complex.
PURITY
MAGNETS
BLU -}---
MAGNETS Y
4-Pole Magnets Movement 6-Pole Magnets Movement
CENTER CONVERGENCE BY
CONVERGENCE MAGNET ASSEMBLY CONVERGENCE MAGNETS
Fig. 11 Fig. 12
16