Service Manual
17-inch Color Monitor
CPQ-C1786FNSL/T
(FS7550/V7550)
Service Manual Versions and Revision
No. Version Release Date Revision
1. 1.0 Dec. 21, 2001 Original release
Copyright
Copyright 2001 LiteOn Technology Corp.
All Rights Reserved
This manual may not, in whole or in part, be copied,
photocopied, reproduced, translated, or converted to
any electronic or machine readable form without
prior written permission of LiteOn Technology Corp.
C1786FNSL/T (FS7550/V7550) Service Manual.
Printed in Taiwan.
Trademarks
LiteOn is a registered trademark of LiteOn
Technology Corp.
All other trademarks are the property of their
respective owners.
CPQ-C1786FNSL/T (FS7550/V7550)
Table of Contents
1. Precautions.........................................................................................................2
2. Product Specifications .......................................................................................5
3 Control Location and Functions ...................................................................... 10
4. Operation Theory.............................................................................................. 11
5. Alignments and Adjustments ........................................................................... 16
6. Troubleshooting............................................................................................... 20
7. Recommended Spare Parts List ....................................................................... 27
8. Block Diagram ................................................................................................ 29
9. Exploded Diagrams .................................................................................. Inserted
10. PCB Diagrams ......................................................................................... Inserted
11. Schematic Diagrams ................................................................................ Inserted
Page 1
CPQ-C1786FNSL/T (FS7550/V7550)
1 Precautions
Follow these safety and servicing precautions to prevent damage and to protect against potential hazards
such as electrical shock and X-rays.
1-1 Safety Precautions
1-1-1 Warnings
1. For safety purpose, do not attempt to modify
the circuit board, and always disconnect the AC
power before performing servicing on the
monitor.
2. Operation of the monitor outside its cabinet or
with the cover removed involves the risk of
shock hazard. Repair work on the monitor
should only be attempted by service personnel
who are thoroughly familiar with all necessary
safety precautions and procedures for working
on high voltage equipment.
3. Do not lift the CRT by the neck. After
completely discharging the high voltage anode,
handle the CRT only when wearing shatterproof
goggles. Try to keep the CRT away from the
body during handling.
4. High voltage should always be kept at the rated
value, no higher. Only when high voltage is
excessive are X-rays capable of penetrating the
shell of the CRT. Operation at high voltages
may also cause failure of the CRT or high
voltage circuitry.
nonmetallic control knobs, insulating materials,
cabinet backs, adjustment and compartment
covers or shields, isolation resistor-capacitor
networks, mechanical insulators, etc.
3. AC Leakage Current Check
Always perform the AC Leakage Current
Check on the exposed metal parts, including
metal cabinets, screwheads and control shafts,
as follows:
a) Plug the AC line cord directly into a rated
AC outlet. Do not use an isolation
transformer during the check.
b) Use an AC voltmeter with at least 5000
ohms per volt sensitivity as follows:
Connect a 1500 ohms, 10 watt resistor
paralleled by a 0.15uF AC capacitor in series
with all exposed metal cabinet parts and a
known earth ground, such as electrical
conduct or electrical ground connected to
earth ground, as shown in the Figure 1-1.
Measure the AC voltage across the
combination of resistor and capacitor.
Figure 1-1. Set Up For AC Leakage Current Check
5. The CRT is especially constructed to limit Xray emission to 0.5mR/HR at 300 microamperes
anode current. To ensure continued X-ray
protection, replace the CRT with only the same
or equivalent type as the original, and adjust the
anodes voltage to the designated maximum
rating, never to exceed.
1-1-2 Safety Checks
Before returning the monitor to the user, perform
the following safety checks:
1. Inspect to make certain that each lead dress is
not pinched or that hardware is not lodged
between the chassis and other metal parts in
the monitor.
2. Inspect all protective devices such as
To kn o w n
earth ground
0.15ufd
1500 ohm 10 watt
To exposed m e tal
cabinet part
c) Reverse the AC plug at the AC outlet and
repeat the steps for AC voltage
measurements for each exposed metal part.
d) Voltage reading must not exceed 0.3 volts
RMS, equivalent to 0.2 milliampere AC. Any
value exceeding this limit ill constitute a
potential shock hazard and must be
corrected immediately.
PrecautionsPage 2
CPQ-C1786FNSL/T (FS7550/V7550)
1-1-3 Product Safety Notices
Many electrical and mechanical parts in this chassis have special safety-related characteristics which are
often not evident from visual inspection, the protection afforded by them may not be obtained by replacing
them with components rated for higher voltage, wattage, etc. Before replacing any of these components,
consult the Recommended Spare Parts List given at the end of this manual. Any of the replacements that do
not provide the same safety characteristics may result in shock, fire, X-ray emission or other hazards.
1-2 Servicing Precautions
Warning: An electrolytic capacitor installed with the wrong polarity might explode.
Caution: Before performing servicing covered by this service manual, read and follow the Safety Precautions
section of this manual.
Note: If unforeseen conflict between the following servicing precautions and any of the safety
precautions, always follow the safety precautions
1. Follow closely the servicing precautions printed on the monitor cabinet and chassis.
2. Always unplug the AC power cord from the AC power source before removing or installing any component
or assembly, disconnecting PCB plugs or connectors and connecting a test component in parallel with a
capacitor.
3. When replacing parts or circuit boards, clamp the lead wires around the component before soldering.
4. When replacing a high wattage resistor (>0.5W metal oxide film resistor) in the circuit board, keep the
resistor about 1 cm (1/2 inch) away from the circuit board.
5. Keep wires away from the high voltage or high temperature components.
6. Keep wires in their original positions so as to minimize interference.
7. Always connect a test instruments ground lead to the instrument chassis ground before connecting the
positive lead; always remove the instruments ground lead last.
After putting the rear cover back and make sure the monitor is working properly, the Hi-Pot &
Ground Continuity tests MUST BE performed before the monitor is returned to user.
1-3 Hi-Pot Test
1. Test Equipment
Puncture test model PM5530 ADT or KIKUSU TOS-8750 voltage tester or equivalent approved equipment.
Note : The test equipment must be calibrated in regular period.
2. Test Setup
a) Apply voltage : DC 2100 VDC
b) Test duration : 3 seconds
c) Cutoff current should be set to 3 mA
3. Test Procedure
a) Unplug power cord from AC source.
b) Put the power switch of the monitor in the ON position.
c) Leave signal cable un-connected.
Precautions
Page 3
d) Plug monitor power cord to the Hi Pot tester terminals.
e) Turn on tester and watch the indicator or beeper.
f) If the indicator lamp lighten, or beeper beeps, the test fails.
1-4 Ground Continuity Test
1. Test Equipment
AC low ohm tester TOS-6100 or equivalent approved equipment.
Note : The test equipment must be calibrated in regular period.
2. Test Setup
a) Test duration : 3 seconds
b) Set current limit at 25 A
c) The grounding resistance must be less than 0.1 ohm.
3. Test Procedure
a) Plug the monitor power cord to the tester terminals.
CPQ-C1786FNSL/T (FS7550/V7550)
b) Make sure all connections are well-contacted.
c) Turn on monitor power and tester power.
d) Press Test button.
e) If green light shows up, means test OK.
If red light shows up, means test fails.
f) If the Tester has a digital display, the resistance value must not exceed 0.1 ohm.
Note : Be sure not to touch the metal portion of the signal cable head during testing.
PrecautionsPage 4
2 Product Specifications
2-1 Specifications
17-inch (15.8-inch Visual image area), sloted mask, 90 degrees
Picture Tube
deflection, dot type black matrix, medium short persistence
phospho r, d ark tint, non-glare / anti- static s creen,
0.25 mm dot pitch
CPQ-C1786FNSL/T (FS7550/V7550)
Sc anning Frequency
Maximum Resolution 1280 dots (H) x 1024 lines (V) @75Hz refresh rate
Display Area 312 mm (H) x 234 mm (V) typical
Display Characters 80 char. x 60 rows on a 10 x 10 matrix
Display C o lo r s Analog
Input
Sync hronizatin Signals Sep arate Sync: horizontal/vertical, TTL, positive or ne gative
Sync hronization
Frequencies
Signal Connectors 15-pin, D-shell connector
Video Signals Analog : 0.7 Vp-p, RGB positive
Power Input 75 Watts (maximum) AC rated voltage, 100VAC to 240VAC
Misconvergence Center Area : <
User Controls Power On/O ff, C ontrast, Brightness, Ho rizonta l Size, Horizonta l
VGA, Super VGA, 1024x768@60/70/75/85/100 Hz
1280x1024@60/75 Hz
Unlimited Colors
Horizontal : 30 to 86 kHz
Vertical : 50 to 140 Hz
0.25 mm; Corner Area : < 0.35mm
Position, Vertical Size, Vertical Position, Pincushion, Trapezoid,
Rotation, Color temperature, Display Frequency, Degauss, Recall,
Pincushion Balance , Parallel,
Service Controls PWB-1619
PWB-1628 : power voltage adjust (VR801), high voltage adjust
Preset Modes 10 (see Table 2-2. Timing Chart)
o
Environmental
Considerations
Operation temperature : 10
Operation Humidity : 20% to 80% ambient
Storage temperature : -40
Storage Humidity : 10% to 90% (non-condensing)
Altitude : Non operating 40,000 feet sea level
operating 10,000 feet sea level
C to 40oC ambient
o
C to 65oC ambient
Note: Above specifications are subject to change without prior notice.
Product Specifications
Page 5
2-2 Signal Cable Pin Connections
Table 2-2. Signal Cable Pin Assignment
Pin Signal Pin Signal
1 Red video 9** +5V
2 Green video 10 Digital Gro und
3 Blue video 11 Ground
4 Ground 12 S DA
5* NC 13 H-Sync
6 Red ground 14 V- Sync/VCL
7 Green gro und 15 S C L
8Blue ground
CPQ-C1786FNSL/T (FS7550/V7550)
Note * This pin is used for selftest detection. Connect this pin to ground at the PC end.
** For PC 99: This pin will provide +5V from PC side.
Product SpecificationsPage 6
CPQ-C1786FNSL/T (FS7550/V7550)
2-3 Timing Chart
This section describes the timings that the computer industry recognizes as standard for computer-generated
video signals.
Table 2-3. Timing Chart
Mode 12345678910
H. Dots 640 640 640 720 800 800 1024 1024 1600 1280
V. D o t s 480 480 480 400 600 600 768 768 1200 1024
H-freq (kHz) 31.469 37.5 43.269 31.467 46.875 53.674 60.023 68.667 81.25 79.976
Sync Polarity ----++++++
A pe riod us 31.778 26.667 23.111 31.778 21.333 18.631 16.66 14.561 12.308 12.504
B Blanking us
C Sy nc us
D B.P. us 1.907 3.81 2.222 1.907 3.232 2.702 2.235 2.201 1.732 1.837
E Active us 25.422 20.317 17.778 25.422 16.162 14.222 13.003 10.836 9.117 9.481
F F. P. us 0.636 0.508 1.556 0.636 0.323 0.569 0.203 0.508 0.365 0.119
V-freq (Hz) 59.94 75 85.008 70.082 75 85.061 75.029 84.997 65 75.025
Sync Polarity ---+++ + +++
G Period ms 16.683 13.333 11.764 14.268 13.333 11.756 13.328 11.765 15.385 13.329
H Blanking ms 1.43 0.533 0.67 1.557 0.533 0.578 0.533 0.582 0.615 0.526
I Sync ms 0.064 0.08 0.069 0.064 0.064 0.056 0.05 0.044 0.037 0.038
J B.P. us 1.048 0.427 0.578 1.111 0.448 0.503 0.466 0.524 0.566 0.475
K Active us
L F. P. us 0.318 0.026 0.023 0.382 0.021 0.019 0.017 0.015 0.012 0.013
6.356 6.35 5.33 6.356 5.172 4.409 3.657 3.725 3.191 3.023
3.813 2.032 1.556 3.813 1.616 1.138 1.219 1.016 1.094 1.067
15.253 12.8 11.093 12.711 12.8 11.179 12.795 11.183 14.769 12.804
Seperate Sync
Horizontal
C
E
Vid eo
D
Sync
A
H.Parameters:
A: Period B: Blanking Time
C: Sync Width D: Back Porch
E: Active Time F: Front Porch
Product Specifications
Ve r t i c a l
B
F
I
K
Vid eo
J
Sync
G
H
L
V.Parameters:
G: Period H: Blanking Time
I: Sync Width J: Back Porch
K: Active Time L: Front Porch
Page 7
CPQ-C1786FNSL/T (FS7550/V7550)
2-4 Power Saving Function
Note: The monitor will be driven into Power Saving mode by the control signal from the display
controller, as indicated by the amber-color power LED.
Table 2-3. Power Saving Function
LE
State Power
Consumption
D
Light
ON Norma
Active
OFF
The power saving states will be kept until a control signal has been detected or the keyboard or mouse is activated.
The recovery time from Active OFF state back to ON state is around 10 seconds.
<5 watts Amber
l*
Green
* For power consumption : 75W Max. (@ 230V AC, preset size and maximum light output condition)
2-5 TCO Version
The monitor meets the TCO 95/99, NUTEK energy saving, electric and magnetic field requirements.
Also it is compliant with TCO 95/TCO 99 labelling scheme.
The emission from magnetic and electric field must comply with the limits specified by the Swedish Board
for Measurement and Testing, commonly known as MPR 1990 recommendations. These limits are summarized in the Table 2-4.
Table 2-5. TCO 95 Emission Requirements
OCT/FLVOCT/FLE
dleiFcitengaMTn52Tn002
dleiFcirtcelEm/V1m/V01
egnaRycneuqerFzHk004~2zH0002~5
eulaVSMRSMR
ecnatsiDmc03mc03
citatsortcelE
laitnetoP
V005-/+V005-/+
The monitor is designed with selected CRT and carefully routed wires around CRT, make sure exactly the
same routing scheme is used when doing CRT replacement.
Product SpecificationsPage 8
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