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CAUTION:
Before servicing this chassis, it is important that the service technician read the "Safety
Precautions" and "Product Safety Notices" in this service manual.
ATTENTION:
Avant d'effectuer l'entretien du châassis, le technicien doit lire les «Précautions de sécurité»
et les «Notices de sécurité du produit» présentés dans le présent manuel.
VORSICHT:
Vor Öffnen des Gehäuses hat der Service-Ingenieur die ,,Sicherheitshinweise" und ,,Hinweise
zur Produktsicherheit" in diesem Wartungshandbuch zu lesen.
SERVICE MANUAL
Data
contained
within
this
Service
manual is subject to alteration for
improvement.
Les données fournies dans le présent
manuel d'entretien peuvent faire l'objet
de modifications en vue de perfectionner
le produit.
Die
in
diesem
Wartungshandbuch
enthaltenen Spezifikationen können sich
zwecks Verbesserungen ändern.
DECEMBER 1999
COLOUR MONITOR
No. 0415
SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT
CM828ET
CM827ET
CM823FET
CM821FET


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2
FEATURES
1. Flat screen CRT with anti-glare, dynamic focus circuit,
dark glass, and INVAR shadow mask give the
sharpest focus and highest contrast.
2. Automatic scanning and automatic adjustment to
conform to a wide range of scanning frequencies and
user requirements.
3. Signal input allows D-Sub Mini 15-pin cable.
4. Power Save Mode automatically puts the monitor into
a standby mode (power consumption less than 15W)
when the H.sync. signal is not detected, and a power -
off mode (less than 5W) when the V.sync. signal is not
detected. Normal mode is restored immediately when
the H. sync. signal and the V.sync. signal are detected.
This feature prolongs monitor life and reduces energy
consumption by up to about 75 %.
SAFETY PRECAUTIONS
NOTICE: Comply with all cautions and safety related
notes located on or inside the cabinet and on the chassis
or picture tube.
The following precautions must 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 while
picture tubes are handled.
2. When replacing a chassis in the monitor, all the
protective devices must be put back in place, such as,
barriers, non-metallic knobs, adjustment and compartment
shields, and isolation resistor-capacitor, etc.
3. When service is required, observe the original lead
dress. Extra precaution should be taken to assure
correct lead dress in the high voltage circuitry area.
4 Always use the manufacturer's replacement components.
Especially critical components as indicated on the
circuit diagram should not be replaced by other
manufacturer's one. Furthermore where a short circuit
has occurred, replace those components that
indicate evidence of overheating.
5. Before returning a serviced monitor to the customer,
the service personnel must thoroughly test 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 monitor by the
manufacturer has become defective, or inadvertently
defeated during servicing.
Therefore, the following checks should be performed
for continued protection of the customer and service
technician.
6. In
the
case
of
the
microprocessor
unit,
shop
adjustment
is
necessary
after
exchange of the
microprocessor unit.
High Voltage
This monitor is provided with a high voltage hold down
circuit for clearly indicating that voltage has increased in
excess of a predetermined value.
Comply with notes described in this Service Manual
regarding this hold down circuit when servicing, so that
this hold down circuit may function correctly.
Service Warning
With minimum Brightness and Contrast the operating
high voltage in this display is lower than 30 kV.
If any component having influence on the high voltage is
replaced, confirm that the high voltage with minimum
Brightness and Contrast is lower than 30 kV.
To
measure
high
voltage
use a high impedance
high-voltage meter.
(SENSITIVE RESEARCH Model:
ESH or Equivalent)
Connect (-) to chassis earth and (+) to the CDT anode
button. (See the following connection diagram Fig. 1.)
NOTE: Turn power switch off without fail before making
the connection to the Anode button
CDT ANODE
HIGH IMPEDANCE
H.V. METER
SENSITIVE RESEARCH
Model: ESH or equivalent.
CHASSIS GROUND
FIG. 1
X-radiation
TUBE: The source of X-radiation in this monitor 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, manufacturer
approved type.
When troubleshooting and making test measurements in
a monitor with a problem of excessive high voltage, avoid
being unnecessarily close to the picture tube and the high
voltage components.
Do not operate the chassis longer than is necessary to
locate the cause of excessive voltage.
CHECK OF HIGH VOLTAGE HOLD DOWN
CIRCUIT
Checking of the high Voltage hold down circuit operation.
1. Turn the switch of the unit ON, and set the Brightness
and Contrast controls to max.
2. Turn the switch of the unit OFF.
3. Connect a DC Voltmeter and an adjustment jig as
shown in Fig. 2.
4. Set the adjustment VR to fully counterclockwise.
5. Turn the switch of the unit ON and gradually rotate the
adjustment VR clockwise.
6. Check that a reading of DC voltage-meter is less-than
0.6
±0.1 V when picture disappears.
7. Turn the switch of the unit OFF immediately after
checking that the picture disappears.
8. Remove the adjusting jig and the DC voltmeter.
NOTE:
Reading of 0.6 V is approximately equivalent to
30 kV of CDT Anode High Voltage.
(+)
(-)


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3
PRODUCT SAFETY NOTICE
Many electrical mechanical parts in the color monitor
units 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 by marking with
on the schematics and on
the parts list in this Service Manual.
The use of a substitute replacement component which
does not have the same safety characteristics as the
manufacturer recommended replacement one, shown in
the parts list in this Service Manual, may create shock,
fire, X-radiation, or other hazards.
Productions are issued from time to time. For the latest
information, always consult this Service Manual.
DC VOLT METER
(10 V range)
VARIABLE
RESISTER
300 k -B (1/2 W)
Clockwise
RESISTER
68 k (1/2W)
To
CHASSIS
GROUND
DEF BOARD ASSEMBLY
FIG. 2 CHECKING CIRCUIT USING JIG
SPECIFICATIONS
Model Name
CM821FET
CM823FET
CM827ET
CM828ET
Destination
Europe
Europe
Europe
Europe
Rated Voltage
AC 100-120 / 200-240 V, Automatically select.
Provided with Power Circuit.
Power Consumption
145 W max (120W typ.)
Color Display Tube
(CDT)
21 inches diagonal, 0.21 mm horizontal dot pitch,
Invar shadow mask, Black matrix, Anti-Reflection coat, Short persis tence phosphors.
Rated
Horizontal
31 - 107 kHz
31 - 121 kHz
31 - 107 kHz
31 - 115 kHz
Frequency
Vertical
50 - 160 Hz
Resolution Horizontal
Up to 1856 dots
Up to 2048 dots
Up to 1856 dots
Up to 2048 dots
Vertical
Up to 1392 lines
Up to 1536 lines
Up to 1392 lines
Up to 1536 lines
Signal Inputs
Red, Green and Blue analog video
H/V separate, H/V composite or Sync. on Green sync (option).
User Controls
Power Switch
Degauss
Language Select
Contrast
Brightness
H. Position
H. Size
V. Position
V. Size
Rotation
Pincushion
Trapezoid
Pin.Balance
Parallelogram
H. Moiré
V. Moiré
Color Select
Red, Green, Blue
DMS Mode
OSD H-Position
OSD V-Position
Dynamic Focus
V.Linearity
V.L. Balance
Hemisphere
Total Reset
Single Recall
Top Corner Pin.
Bottom Corner Pin.
H. Convergence adj.
V. Convergence adj.
Environmental
Condition
Operation
Storage
Temperature
:
5 to 35
-20 to 60
Humidity
:
10 % to 80 %
10 % to 90 %
Dimensions
488(W) × 483 (H) × 475 (D) mm *
488(W) × 483 (H) × 470 (D) mm *
Weight
30.5 kg(Net)
27.0 kg(Net)
* Including Tilt & Swivel base
V
R793
R792


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4
CONTROLS
FIG. 3 FRONT VIEW
D-Sub Mini 15-pin
CRT Surface
Front Cover
Control Panel
Tilt & Swivel Base
FIG. 4 CONTROL PANEL
Power Switch
FIG.3 FRONT VIEW
FIG. 5 REAR VIEW
AC Inlet
Signal Cable
(D-Sub Mini 15-pin)


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5
SIGNAL TIMING CHART
Signal
VGA
640
×400
(70Hz)
VESA
800
×600
(85Hz)
VESA
1024
×768
(85Hz)
VESA
1280
×1024
(85Hz)
CM82
1F
CM82
1FET
1
Video
Type
R/G/B Analog
R/G/B Analog
R/G/B Analog
R/G/B Analog
Voltage
0.7 Vp-p
0.7 Vp-p
0.7 Vp-p
0.7 Vp-p
Set Up
None
None
None
None
2
Sync
Type
H/V Separate
H/V Separate
H/V Separate
H/V Separate
Amp.
TTL Level
(Neg./Pos.)
TTL Level
(Pos./Pos.)
TTL Level
(Pos./Pos.)
TTL Level
(Pos./Pos.)
3
Video frequency
25.175 MHz
56.250 MHz
94.500 MHz
157.500 MHz
4
Character (Letter)
640 dots
×400 lines
800 dots
×600 lines
1024 dots
×768 lines
1280 dots
×1024 lines
5
Horizontal
Frequency
31.469 kHz
53.674 kHz
68.677 kHz
91.146 kHz
Front
porch
0.636 µs
(16cl)
0.569 µs
(32cl)
0.508 µs
(48cl)
0.406 µs
(64cl)
Sync.
width
3.813 µs
(96cl)
1.138 µs
(64cl)
1.016 µs
(96cl)
1.016 µs
(160cl)
Back
porch
1.907 µs
(48cl)
2.702 µs
(152cl)
2.201 µs
(208cl)
1.422 µs
(224cl)
Blanking
width
6.356 µs
(160cl)
4.409 µs
(248cl)
3.725 µs
(352cl)
2.844 µs
(448cl)
Display
time
25.422 µs
(640cl)
14.222 µs
(800cl)
10.836 µs
(1024cl)
8.127 µs
(1280cl)
H. period
(1H)
31.778 µs
(800cl)
18.631 µs
(1048cl)
14.561 µs
(1376cl)
10.971 µs
(1728cl)
6
Vertical
Frequency
70.086 Hz
85.061 Hz
84.997Hz
85.024 Hz
Front
porch
0.381 ms (12H)
0.019 ms (1H)
0.015 ms (1H)
0.011 ms (1H)
Sync.
width
0.064 ms (2H)
0.056 ms (3H)
0.044 ms (3H)
0.033 ms (3H)
Back
porch
1.112 ms (35H)
0.503 ms (27H)
0.524 ms (36H)
0.483 ms (44H)
Blanking
width
1.557 ms (49H)
0.578 ms (31H)
0.582 ms (40H)
0.527 ms (48H)
Display
time
12.711 ms (400H)
11.179 ms (600H)
11.183 ms (768H)
11.235 ms (1024H)
H. period
(1H)
14.268 ms (449H)
11.756 ms (631H)
11.765 ms (808H)
11.761 ms (1072H)
7
Scan System
(Non-interlaced)
(Non-interlaced)
(Non-interlaced)
(Non-interlaced)
8
Signal name
30B
54A
68A
91A
* VGA is a registered trademark of International Business Machined Corporation.
* VESA is a trademark of a nonprofit organization, Video Electronics Standard Association.