LITE-ON A1770 Service Manual

Service Manual

17-inch Color Monitor A1770NSL/NST

Service Manual Versions and Revision

No. Version Rele ase Date Revision

1. 1.0 July 17, 1998 Original release

copied, photocopied, reproduced, translated, or converted to any electronic or machine readable form without prior written permission of LiteOn T echnology Corp.

A1770NSL/NST Service Manual.

Printed in Taiwan.

T rademarks

LiteOn is a registered trademark of LiteOn Technology Corp.

All other trademarks are the property of their respective owners.

A1770NSL/NST

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............................................................................................... 21

7. Recommended Spare Parts List....................................................................... 27

8. Block Diagram ................................................................................................ 29

9. Exploded Diagrams.................................................................................. Inserted

10. PCB Diagrams......................................................................................... Inserted

11. Schematic Diagrams ................................................................................ Inserted

Page 1

A1770NSL/NST

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 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

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.

PrecautionsPage 2

A1770NSL/NST

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 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.

A1770NSL/NST

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

Picture Tube

degrees deflection, dot type black matrix, medium short

persistence phosphor, dark tint, non-glare/ anti-static screen,

0.27 mm dot pi tch

A1770NSL/NST

Sc anning F req uency

Maximum Resolution 1280 dots (H) x 1024 li nes (V) @60Hz refresh rate Display Area 300 mm (H) x 225 mm (V) typical Display Characters 80 char. x 60 rows on a 10 x 10 matrix Display Colors Analog

Input Sync hroni zati n Signa ls Se par ate Sync: hori zonta l/verti ca l, T TL, posi tiv e or negati ve Sync hroni zati on

Fr eque ncies Si gnal Conne ctor s 15 -pi n, D- shel l connector Video Si gnals Anal og : 0.7 Vp-p, RGB positi ve Power Input 95 Watts (maximum) AC rated voltage, 100VAC to 240VAC Misconvergence Center Area : <

Us er Control s

VGA, Super VGA, 1024x768@60/70/75/85 Hz,

1280x1024@60 Hz

Unlimited Colors

Horizontal : 30 to 69 kHz Vertical : 55 to 120 Hz

0.3 mm; Corner Area : < 0.4mm

Power On/Off, Cont ras t, Br ightne ss, Horizonta l Si ze, Horizontal Position, Vertical Size, Vertical Position, Pincushion, Trapezoid, Rotation, Color temperature, Langua ge, Di spl ay Freque ncy, Dega uss, Recall, H. Moire, V. M o i r e

Service Controls PWB-1410 : R-bias (VR910), G-bias (VR940),

B-bias (VR970), PWB-1440 : power voltage adjust (VR801),

high voltage adjust (VR802), focus1, focus2 Preset Modes 13 (see Table 2-2. Timing Chart) Envir onmental

Considerations

Operation temperature : 5 Operation Humidity : 20% to 80% ambient Storage temperature : -40 Storage Humidity : 5% to 95% (non-condensing)

Altitude : up to3000m above sea level

C to 4 0oC ambient

C to 6 5oC ambient

Note: Above specifications are subject to change without prior notice.

Product Specifications

Page 5

2-2 Signal Cable Pin Connections

Table 2-1. Signal Cable Pin Assignments

Pin S ignal Pin Signal

A1770NSL/NST

1 Red video 9

2 Green video 10 Digital Ground 3 Blue video 11 Ground 4 G r o und 12 SDA 5

13 H - Sync 6 Re d gr ound 14 V- Sync/ VCL 7 Gre en gr ound 15 SCL 8 Bl ue g ro und

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

Product SpecificationsPage 6

A1770NSL/NST

2-3 Timing Chart

This section describes the timings that the computer industry recognizes as standard for computer-generated video signals.

T able 2-2. Timing Chart

Mode 1 2 3 4 5 6 7 8 9 10 11 12 13

H. D ots 720 640 640 800 640 640 800 1024 800 1024 1024 1280 1024

V. D o t s

H-freq (kHz) 3 1. 47 31.47 3 5 37.88 37.5 43. 3 46.8 4 8. 36 53.67 56.48 60.02 64.34 68.68

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

A pe riod us 31.78 31.78 28.57 2 6.4 26. 666 23.111 21.33 3 2 0.68 18.63 17. 71 1 6.66 15.55 14.56

B Blking us 6.356 6.356 7.407 6.4 6.35 5.33 5.172 4.923 4.409 4.053 3.657 3.589 3.725

C S ync us 3.81 3.81 2.116 3.2 2.07 1.556 1.616 2.092 1.138 1.813 1.219 0.972 1.016

D B.P. us 1.907 1.907 3.175 2.2 3.81 2.222 3.232 2.462 2.702 1.92 2.235 2.248 2.201

E Acti ve us

F F. P. us 0.636 0.636 2.116 1 0.51 1.556 0.323 0.369 0.569 0.32 0.203 0.374 0.508

V-freq (Hz) 70.08 59.95 66.667 60.32 75 85 75 60 85 70.07 75.03 60 85

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

O Period ms 14.27 16.68 1 5 16.58 13.33 11.764 13. 333 16.67 11.76 1 4.27 13.33 16.67 11.77

P B lking ms 1.557 1.43 1.286 0.739 0.533 0.67 0.533 0.786 0.578 0.673 0.533 0.642 0.582

Q Sy nc ms 0.064 0.064 0.086 0.106 0.08 0.069 0.064 0.124 0.056 0.106 0.05 0.047 0.044

400 480 480 600 480 480 600 768 600 768 768 1024 768

25.42 25.42 21. 164 20 20.32

17.778

16.162 15.75 14.22 13.65 13 11.96

10.836

R B.P. us 1.08 1.02 1.14 0.607 0.407 0.578 0.448 0.6 0.503 0.513 0.466 0.501 0.524

S Active us 12.71 1 5.25 13. 714 15. 84 12.8 11.09 3 1 2.8 15.88 11.18 1 3.6 12.8 1 6.03 11. 18

T F.P. us 0.413 0.35 0.086 0.026 0.026 0.023 0.021 0.062 0.019 0.053 0.017 0.094 0.015

Seperate Sync

H orizontal

Video

Sync

H.Parameters:

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

Product Specifications

Vertical

V.Parameters:

G: Period H :Blanking Time I: Sync Width J: Back Porch K: Active T ime L : Front Porch

Video

Sync

Page 7

A1770NSL/NST

2-4 Display Power Management Signal (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 Signal (DPMS) .

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

State LED Color H-Sync V-Sync Power

Co nsumpti o n

ON Green Pulse Pulse Normal

STANDBY Yellow No Pulse Pulse <15 watts

SUS PEN D Ye llow Puls e N o P ulse < 15 wa tts

O FF Amb er N o Puls e No Puls e <8 wa tt s

2-6 TCO Version (Optional)

The monitor meets the TCO 92, NUTEK energy saving, electric and magnetic field requirements. Also it is compliant with TCO 95 (optional) labelling scheme.

2-6-1 TCO 92 Version

The emission from magnetic and electric field must comply with the limits specified by the Swedish Board for Measurement and T esting, commonly known as MPR 1990 recommendations. These limits are summarized in the T able 2-4.

T able 2-4. TCO 92 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 for CRT replacement.

Product SpecificationsPage 8

A1770NSL/NST

2-6-2 TCO 95 Version (Optional)

The TCO 95 scheme is for international and environmental labelling of personal computers. The labelling scheme was developed as a joint effort by the TCO (The Swedish Confederation of Professional Employ ees), Naturskyddsforeningen (The Swedish Society for Nature Conservation) and NUTEK (The National Board for Industry and T echnical Development in Sweden).

1) Scope TCO 95 touches on ergonomic qualities, emissions (electrical and magnetic fields), energy efficiency and

ecology (with demands for environmental adaptation for both the product and the production processes at the manufacturing plant).

2) Environmental Requirements The monitor abides by the environmental demands concerning restrictions on the presence and use of

heavy metals, brominated and chlorinated flame retardants, CFCs (freons), and chlorinated solvents, among other things. The monitor is also recyclable.

3) Energy Requirements The monitor also follows the energy requirements that, after a certain period of inactivity, the monitor

shall reduce its power consumption to a lower level in one or more stages.

4) Others The monitor meets the strict environmental demands for the reduction of electric and magnetic fields,

physical and visual ergonomics and good usability.

Table 2-5. TCO 95 Visual Ergonomics

erutaeFdradnatSnoitpircseD

ytiraeniLsselro%1 ehtotderapmocsworrosnmulocfohtgnelniecnereffiD

ecnanimuLyalpsiD)tsaelta(2m/dc001

ecnanimuL ytimrofinU

sselro1:7.1 ehtnihtiwecnanimulnimotxamehtneewtebsioitarehT

.aeraevitcaelohw

.rotinomehtforetnecehthguorhtshtgnelgnidnopserroc

Product Specifications

Page 9

3 Control Location and Functions

(1) (2) (3) (6)(5)(4)

3-1 Front Panel

A1770NSL/NST

(1) Function Key (2) Decrease Key (3) Increase Key (4) Select Key (5) Power LED (6) Power ON/OFF

3-2 Front Panel Keys Functions

1. Function Key: Display the main menu, and exit the adjustment screen and save adjustments.

2. Decrease Key: Scroll across main menu, highlighting control to be adjusted. Decrease value of selected control. Toggle between Contrast and Brightness adjustment screens.

3. Increase Key: Scroll across main menu, highlighting control to be adjusted. Increase value of selected control. Toggle between Contrast and Brightness adjustment screens.

4. Select Key: Press once to display adjustment screen. Press again, for some controls, to toggle between controls shown in pairs on main menu.

5. Power LED: Display different modes (ON, standby, suspend or OFF) of the monitor by showing different color for each mode.

6. Power ON/OFF: To turn the monitor ON and OFF.

3-3 Adjustment Procedure

1. Press (6) key to turn on the monitor.

2. At normal condition, press (1)on the front panel to activate the on-screen manager (OSM) menu. But to enter the internal adjustment menu, keep pressing (1) & (4) key simultaneously and then press (6) key.

3. To select a user control, press (2) or (3) key repeatedly until the control is highlighted.

4. To adjust the value for particular control, press (4), then press the (2) or (3) key to obtain the desired value. There are a few parameters that do not require any adjustment, like Manual Degauss, Memory Recall.

5. Some controls are grouped in pairs on the main menu. Press (4) key to toggle between them.

6. To save your adjustments and exit screen, press (1) key. The menu will automatically clear out from the screen if no keys are pressed within 30 seconds.

Page 10 Operation Theory

+ 25 hidden pages

LITE-ON A1770 Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual