LITE-ON A1454, A1554 Service Manual

Service Manual

A1454 / A1554NEL
Color Monitor

Service Manual V ersions and Revision

No. Vers ion Release Date Revision

1. 1.0 May 28, 1998 Original release

2 1.1 June 19, 1998 4-1- 3 (3)

4-2 - 2 Screen and White Balance Adjustment
6 (15) update model
6 (16) add spare parts

3 1.2 July 8, 1998 2-6 DPMS (Page 9)

3 (Page 10)

Copyright

Copyright 1998 LiteOn T echnology 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
T echnology Corp.

A1454 / A1554 NEL Service Manual.

Printed in T aiwan.

T rademarks

LiteOn is a registered trademark of LiteOn
T echnology Corp.

All other trademarks are the property of their
respective owners.

A1454 / A1554 NEL

Table of Contents

1. Precautions................................................................................................. 2

2. Product Specifications .............................................................................. 5

3. Operation Theory ...................................................................................... 9

4. Alignments and Adjustments .................................................................... 13

5. Troubleshooting......................................................................................... 17

6. Recommended Spare Parts List ................................................................ 21

7. Block Diagram .......................................................................................... 23

8. Exploded Diagrams..................................................................................... Inserted

9. PCB Diagrams ............................................................................................ Inserted

10. Schematic Diagrams................................................................................... Inserted

1

A1454 / A1554 NEL

g

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 CR T with only the same
or equivalent type as the original, and adjust the
anode’s 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

2 Precautions2

To kn own

earth

round

0.15ufd

1500 ohm 10 w att

To ex posed 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 .

A1454 / A1554 NEL

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 instrument’s ground lead to the instrument chassis ground before connecting the

positive lead; always remove the instrument’ s 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 T est

1. T est 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) T est 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

3

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 T est

1. T est 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.

A1454 / A1554 NEL

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 T ester 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.

4 Precautions4

2 Product Specifications

2-1 Specifications

A1454 / A1554 NEL

Picture Tube

Scanning Frequency VGA, Super VGA, 800x600@60/72/75/85 Hz, 1024x768@60 Hz

Maximum Resolution 1024 dots (H) x 768 li nes (V) @60Hz refresh rate

Display Area 14-inch 250 mm (H) x 187 mm ( V) typical

Display Characters 80 char. x 60 rows on a 10 x 10 matrix

Display Colors Analog Input Unlimited Colors

Sync hroni zati n Signal s Se par ate S ync: ho ri zontal /ve rti cal , T TL, pos iti ve o r nega tiv e

Sync hroni zati on Fre quenc ies

Si gnal Co nnecto rs 15 -pi n, D-s hel l co nnecto r

Vi deo Signals Analog : 0.7 Vp-p, RG B p ositive

14-inch (13.3-inch Visual image area),
15-inch (14.0-inch Visual image area)

slote d ma sk, 90 degrees de flectio n, d ot type black matrix, medium s ho rt

persistence phosphor, dark tint, non-glar e/ anti-static screen, 0.28 mm dot
pitch

15-inch 262 mm (H) x 196 mm ( V) typical

Horizontal : 30 to 54 kHz
Vertical : 50 to 120 Hz

Powe r Inp ut

Misconvergence Center Area : <

User Controls Power On/Off, Contrast, Brightness, Vertical Sizs, Vertical Position,

Service Controls PWB-1402 : R-bias (VR910), G-bias (VR940), B-bias (VR970),

Preset Modes 12 (see Tabl e 2-2. Timing Chart)

Environmental Considerations Operati on temperature : 5

14-i nch 7 0 Watts ( nominal ) AC rated vol tage, 100VAC to 264VAC

15-i nch 7 5 Watts ( nominal ) AC rated vol tage, 100VAC to 264VAC

0.3 mm; Corner Area : < 0.4 mm

Horizontal Positi on, Horizontal Size, Pincushion, Trapezoid,

R-gain (VR599), G-gain (VR598)
PWB-1405 : power vol tage adjust (VR801), high voltage ad just (VR80 2),
, focus

o

C to 40oC ambient

o

Storage temperature : 0

Humidity : 5% to 95% ambient

Storage Humidity : 5% to 95% (non-condensi ng)

Altitude : up to 3000m a bove sea l evel

C to 65oC ambient

Note: The above specifications are subject to change without prior notice.

Product Specifications

5

5

2-2 Signal Cable Pin Connections

Table 2-1. Pin Assignments

Pin Sig nal Pin Sig nal

1 Red video 9 No pin

2 Gr ee n vid eo 1 0 Dig ita l Gr ou nd
3 Blue video 11 Gro und
4 Gr ound 12 SDA
5* Selftest 13 H-Sync
6 Re d gr ound 14 V -Sync /VC L
7 Gr een ground 15 SC L

A1454 / A1554 NEL

8Blue ground

Note: * This pin is used for selftest detection. Connect this pin to ground at the PC end.

6 Product Specifications6

A1454 / A1554 NEL

2-3 Timing Chart

This section of the service manual describes the timing that the computer industry recognizes as standard for
computer-generated video signals.

Table 2-2. T iming Chart

Mode 123456789101112
H. Do ts 720 720 640 640 640 800 800 800 800 640 1024 800
V. Dot s 350 400 480 480 480 600 600 600 600 480 768 600
H-freq (k Hz) 31.47 31.47 31.47 37.86 37.5 35.16 37.88 46.875 48.08 43.3 48.36 53.674

Sync Polarity +-- - -+/-+ + + - - +

A Perio d us 31.78 31.78 31.78 26.413 26.666 28.44 26.4 21.333 20.8 23.11 20.677 18.6
B Blking us 6.356 6.356 6.356 6.095 6.35 6.22 6.4 5.172 4.8 5.333 4.923 4.409

C Sy nc us 3.81 3.81 3.81 1.27 2.07 2 3.2 1.616 2.4 1.556 2.09 1.138

D B.P. us 1.907 1.907 1.907 4.06 3.81 3.556 2.2 3.232 1.28 2.222 2.462 2.702
E Acti ve us 25.42 25.42 25.42 20.317 20.32 22.22 20 16.162 16 17.778 15.75 14.222
F F.P. us 0.636 0.636 0.636 0.76 0.51 0.667 1 0.323 1.12 1.556 0.369 0.569

V-freq (H z) 70.08 70.08 59.95 72.81 75 56.25 60.32 75 72.18 85 60 85
Sync Polarity -+- - - +/-+ + + - - +
G Period ms 14.27 14.27 16.68 13.735 13.33 17.78 16.58 13.333 13.87 11.764 16.67 11.8

H Blking ms 3.146 1.557 1.43 1.057 0.533 0.711 0.739 0.533 1.373 0.67 0.786 0.578

I Sync ms 0.064 0.064 0.064 0.079 0.08 0.057 0.106 0.064 0.125 0.069 0.124 0.056

J B.P. ms 1.87 1.08 1.02 0.74 0.407 0.626 0.607 0.448 0.478 0.578 0.6 0.503

K Active ms 11.12 12.71 15.25 12.678 12.8 17.07 15.84 12.8 12.51 11.093 15.88 11.179

L F. P. ms 1.21 0.413 0.35 0.238 0.026 0.0284 0.026 0.021 0.770 0.023 0.062 0.019

Video

A

E

B

F

Sync

H orizontal

D

C

H.Parameters:

A: Period B: Blanking Time
C: Sync Width D:Back Porch
E : Active Time F: Front Porch

Seperate Sync

Ver tic a l

V .Parameters:

G : Period H: Blanking Time
I: Sync W idth J: Back Porch
K: Active Time L: Front Porch

K

Video

J

Sync

I

G

H

L

Product Specifications

7

7

A1454 / A1554 NEL

2-4 Display Power Management Signaling (DPMS)

Note: These power-saving states exceed the Environmental Protection Agency (EPA) Energy Star

requirements and the Video Electronics Standard Association (VESA) for Display Power
Management Signaling (DPMS) .

T able 2-3. Display Power Management Signaling (DPMS)

State LED Color H-Sync V-Sync Power

Co ns umptio n

ON Green Pulse Pulse Normal

STANDBY Yellow No Pulse Pulse <15 watts

SUSPEND Yellow Pulse No Pulse <15 watts

OFF Amber No Pulse No Pulse <5 watts

8 Product Specifications8