LITE-ON C1996PNS Service Manual

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Service Manual

19-inch Color Monitor C1996NSL/NST/PNST

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Service Manual Versions and Revision

No. Version Release Date Revision

1. 1.0 Dec. 5, 2001 Original release

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.

C1996NSL/NST/PNST 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.

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C1996NSL/NST/PNST

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

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C1996NSL/NST/PNST

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

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To kno 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.

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C1996NSL/NST/PNST

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.

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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.

C1996NSL/NST/PNST

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.

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C1996NSL/NST/PNST

2 Product Specifications

2-1 Specifications

19-inch, (18-inch visual image area) sloted mask, 90 degrees

Picture Tube

Scanning Frequency VGA, Super VGA, 1024x768@75/85 Hz, 1280x1024@85 Hz

Maximum Resolution 1600 dots (H) x 1200 lines (V) @75Hz refresh rate

Display Area 350 mm (H) x 262 mm (V) typical

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

deflection, dot type black matrix, medium short persistence

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

0.26 mm dot pitch

Display Colors Analog Input

Synchronizatin Signals Separate Sync: horizontal/vertical, TTL, positive or negative

Synchronization Frequencies

Signal Connectors 15-pin, D-shell connector

Video Signals Analog : 0.7 Vp-p, RGB positive

Power Input 120 Watts (maximum) AC rated voltage, 100VAC to 240VAC

Misconvergence Center Area : <

User Controls

Service Controls PWB-1596/1598 : power voltage adjust (VR801)

Preset Modes 10 (see Table 2-2. Timing Chart)

Unlimited Color s

Horizontal : 30 to 96 kHz Vertical : 50 to 160 Hz

0.3 mm; Corner Area : < 0.4mm

Power On/O ff, C ontrast, Brightness, Horizontal Size, Horizontal Position, Vertical Size, Vertical Position, Pincushion, Trapezoid, Pin Balance, Parallelogram, Rotation,

Color temperature, Language, Display Frequency, Degauss,

Recall, H. Moire, V. Moire

focus 1 , focus 2

Environmental 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 35oC ambient

C to 65oC ambient

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

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2-2 Signal Cable Pin Connections

Table 2-1. Signal Cable Pin Assignment

Pin Signal Pin Signal

1Red video 9 +5V

2 Green video 10 Digital Ground

3 Blue video 11 Ground

4 Ground 12 SDA

5* Ground 13 H- Sync

6 Red ground 14 V- Sync/VC L

7 Green ground 15 SCL

8 Blue ground

C1996NSL/NST/PNST

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

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C1996NSL/NST/PNST

2-3 Timing Chart

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

Table 2-2. Timing Chart

Mode 12345678910

H. Dots 640 720 640 832 800 1152 1024 1600 1280 1600

V. D o t s 480 400 480 624 600 870 768 1200 1024 1200

H-fre q (kHz) 31.47 37.927 43.27 49.725 53.67 68.681 68.67 75 91.146 93.75

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

A pe riod us

B Bla nking us 6.356 6.085 5.33 5.586 4.409 3.04 3.725 3.457 2.844 2.765

C Sync us 3.81 2.028 1.556 1.117 1.138 1.28 1.016 1.185 1.016 0.948

D B.P. us 1.907 3.042 2.22 3.91 2.702 1.44 2.201 1.877 1.422 1.501

E Active us 25.42 20.282 17.78 14.524 14.222 11.52 10.836 9.877 8.127 7.901

F F. P. us 0.636 1.014 1.556 0.559 0.569 0.32 0.508 0.395 0.406 0.316

V-freq (Hz) 59.94 85 85 74.55 85 75.062 84.99 60 85 75

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

G Period ms 16.68 11.759 11.76 13.414 11.756 13.322 11.765 16.667 11.761 13.333

H Blanking ms 1.43 1.213 0.67 0.864 0.578 0.656 0.582 0.667 0.527 0.533

I Sync ms

J B.P. us 1.02 1.107 0.578 0.764 0.503 0.568 0.524 0.613 0.483 0.491

K Active us 15.25 10.546 11.09 12.549 11.179 12.667 11.183 16 11.235 12.8

L F.P. us 0.35 0.026 0.023 0.04 0.019 0.044 0.015 0.013 0.011 0.011

31.78 26.366 23.11 20.11 18.631 14.561 14.561 13.333 10.971 10.667

0.064 0.079 0.069 0.06 0.056 0.044 0.044 0.04 0.033 0.032

Seperate Sync

Horizontal

Vid eo

Sync

H.Parameters:

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

Ve r ti c a l

Vid eo

Sync

V.Parameters:

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

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C1996NSL/NST/PNST

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

State Power

Consumption

ON <120 watts Green

Light

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.

<3 watts Amber

2-5 TCO Version (Optional)

The monitor meets the TCO 99, NUTEK energy saving, electric and magnetic field requirements.

2-5-1 TCO 99 Version (Optional)

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 2-4. TCO 99 Requirements

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C1996NSL/NST/PNST

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.

The TCO 99 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 Technical Development in Sweden).

1)`Scope

TCO 99 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 99 Visual Ergonomics

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3 Control Location and Functions

C1996NSL/NST/PNST

(1) (2)

(3) (4)

(5) (6)

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

3-1 Front Panel

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, 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.

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

4. To adjust the value for a 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.

Note: To enter the Internal Adjustment mode, press (1) & (4) keys simultaneously then press (6).

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C1996NSL/NST/PNST

4 Operation Theory

This is a fully digital controlled multi-sync color monitor that is compliant with DDC1/2B Plug and Play VESA standard and offers the following main features.

4-1 Main Features

1. Simplified design with minimum components.

2. The NOVATEK NT68P65AU processor-- that has I

brightness-- offers the functions for: (a) Contrast, (b) Brightness, (c) H-size, (d) H-position, (e) V-size, (f) V-position, (g) Pincushion, and (h) Trapezoid, (i) Pin Balance, (j) Parallelogram.

C bus controlled geometric correction, contrast and

In addition, it also offers more functions as: (a) Sync. processor, I/P and O/P, (b) Mute, (c) Power saving off, (d) Power saving override, (e) DDC2B, (f) I

C Bus for auto-alignment through signal cable (g) CS

switching for linearity and size compensation, (h) High voleage adjustment, (i) G2 voltage adjustment.

3. Stores up to 10 factory preset modes and offers 6 user modes. There are 18 function icons in OSD. They

are controlled by

2 keys on the front panel.

4. Powerful PHILIPS TDA4841 and TDA4863 present the following useful functions: (a) Pincushion, (b)

Trapezoid, (c) V-Position, (d) V-Size, (e) Verticals C and S correction -- factory adjust, (f) Pincushions V. position correction, (g) Corner correction -- factory adjust, (h) Pincushion unbalance correction -factory adjust, (i) Parallelogram distortion -- factory adjust, (j) Moire cancellation, (k) X-ray protection, and (l) Full horizontal and vertical auto sync capability.

5. Software controlled auto shut off function activated if fH < = 29 kHz and fH > = 96 kHz.

6. Full range AC input and simplified line filter design.

4-2 Microcontrol Section

1. This monitor uses NOVATEK NT68P65AU CPU. It contains a 8-bit CPU core, 256 bytes of RAM used

as working RAM and stack area, 24k bytes of OTP ROM, 14-channel 8 bit PWM D/A converter, 2channel A/D converters for key detection saving I/O pins, internal H. sync and V. sync signals processor providing mode detection, and an I2C bus interface. When H/V sync through D-Sub signal cable enter pin 41 and pin 42, the CPU performs frequency / polarity detection and calculate and send to H/V sync OUT. Then CPU reads the data from I703 and transfer to device 4841 and some DAC in CPU, above operation takes about 500 ms.

2. There allows 10 factory preset modes and 6 user modes. There are 8 functions, Contrast, Brightness, H.

Size, H. Position, V. Size, V. Position, Pincushion, and Trapezoid, all controlled by OSD icon which can be adjusted by user.

3. The pin 25 and pin 26 are used for ATE function. When CPU receives C6 as slave address, it will operate

in ATE mode which is used for auto-alignment. After alignment the data will be stored in I703.

4. The user control parameters are selected by OSD icons, through

2 keys, they are detected by

sensing the voltage through R710, R759, R713, R714, R709, R711, R760 to pin 16 and 17 of I701.

4-3 Deflection Section

1. I2C -- autosync deflection controller is TDA4841.

2. The TDA4841 is a high performance and efficient solution for autosync monitors. All functions are

controllable by I control all functions.

C bus. SDA and SCL signals coming from microprocessor feed to pin 19 and pin 18 to

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C1996NSL/NST/PNST

4-3-1 Horizontal Section

1. The oscillator is driven by the currents in R472 and R468. The minimum oscillator frequency is determined by R472 and the maximum frequency is determined by R468.

2. Horizontal sync goes into pin 15 through R494. And horizontal flyback pulse goes into pin 1 through R479 and bypass filter C445 from Emitter of Q407 and C412, C433, C411, R419, C456, R421, D413 for AFC loop.

3. Horizontal driver (pin8) output to Q401 via C401, Q401 switching to drive T401 provide IB1/IB2 current then turn on/off Q402 and switching the yoke current.

4-3-2 Vertical Section

1. Vertical sync goes into pin 14 through R493.

2. The free running frequency is determined by R470 and C442.

4-3-3 Vertical O/P section

1. The differential output currents from pin 13 of Vout1 and pin 12 of Vout2 can be directly coupled to the vertical deflection booster pin 3 and pin 2 of TDA4863.

2. The TDA4863 has two output stages which are current driven in opposite phase and operate in combination with the deflection coil in a half bridge configuration.

3. This IC is powered by three sets of positive voltage. (+13V at pin1, 37V at pin 8, -13V at pin 6)

4-3-4 E-W/Trapezoid and H. Width Controls

1. The scan current is determined by B+ (the voltage of C413) that is obtained from step down circuit output. Step down circuit include Q404, T402, D407.

2. I401 TDA4841 pin 6 (B DRV) will drive the step down circuit to change H. width.

3. EW DRV (pin11) provides a complete EW drive waveform including parabola, corner and trapezoid correction and feed to BIN (pin 5 of I401) to get a good control for pincushion / trapezoid / corner.

4. The top and bottom corner correction can be adjusted seperately.

4-3-5 X-Ray Protection

1. To avoid X-ray hazard, a DC voltage generated at pin 6 of FBT and rectified by D107, C111 and divided by R476, R477 and R478 come into pin 2 of TDA4841.

2. If this voltage is higher than 6.39 V, then TDA4841 will be activated to float HUNLOCK (pin17), H. DRV( pin 8), B DRV (pin 6), VOUT1 (pin 12), VOUT2 (pin13). After that all deflection circuit stop working.

4-3-6 Blanking and Brightness

1. The vertical blanking signal comes from I401 pin 16 and vertical sync. These two pulses combine into Q542 and Q541. This signal feets into T501 pin 24.

2. In protection mode or out of range or mode change mute signal will turn high and turn on Q107. G2 voltage will drop from 600V to 250V.

3. The brightness is control by I

C bus. The output pins are I501 pin 14, pin 15, pin16.

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C1996NSL/NST/PNST

4-3-7 Contrast Section

1. Contrast is controlled by I701 through I2C bus to I501 (LM1267) directly.

2. Beam current is detected through T101 (FBT) pin 7, D106, C109, Q102, R108, R121, R122 to control

I501 pin 22 voltage. When I501 pin 22 voltage drops below 5V, the ABL function will happen.

4-3-8 Dynamic focus circuitry

The dynamic focus is applied to improve the corner focus performance, it includes horizontal and vertical dynamic focus.

1. Vertical dynamic comes from I401 pin 32 and is amplified through C105, Q101, C137, and feed to FBT

dynamic focus pins R133, R132, Q101.

2. This amplifier need 200V voltage supply, it comes from FBT pin 8 and rectified through L102, D101, and

C102.

4-4 Power Supply Section

4-4-1 AC Rectifier

The circuit can accept 90 V to 264 V AC input through D801 bridge diodes and C808 filtering to get DC 126 V~364 V for power conversion in T802.

4-4-2 Line Filter

It consists of C801, C802, C803, C816, C820, C823, T801, T804 and meets EMI regulation.

4-4-3 Power LED Status

1. The LED has 3 leads with common cathode to emit green and amber color light for different power

saving states.

2. Normal : Green light

3. Off Mode : Amber light

4-4-4 Auto Degaussing

When S801 turns on, pin 27 of I701 will send a signal to Q802 and turns on RL801 for degaussing. After 4 seconds, it will turn off RL801 automatically.

4-4-5 PWM Control

1. Start Up

The I801 (KC3843B) gets power from R846, Q821, R849, R848, D826, D828, D822 and pin 7 voltage reaches 8 V for starting up. The I801 starts oscillation at 22 kHz, sawtooth on pin 4 and pin 6 output to drive Q803/T802. Once Q803 switching on, D806, C804 set up an 15 V to keep I801 working through D821 auxiliary voltage.

2. Regulation

The DC O/P voltage is proportional to the auxiliary voltage, so I801 pin 2 senses the feedback voltage from the divider R802, R823, VR801 and R820 to compare with the built-in 2.5 volts reference voltage for error amplifier operation. Finally pin 6 can modulate the different duty cycle by VR801 setting to achieve regulation purpose.

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C1996NSL/NST/PNST

4-4-6 Synchronization

1. Normal Mode The sync pulse from FBT (31 kHz~95 kHz) via R812, R831, C815, R826, D824, C814 and R816 to pin 4

of I801 to keep I801 synchronized with horizontal sync input frequency.

2. Power Saving Modes: Off mode Because there is no pulse from FBT, so the free-run frequency is decided by R817 and C814 and the

SMPS works at 22 kHz.

3. Override The horizontal free run frequency is about 62.5 kHz under override condition, SMPS is synchronized to

this frequency.

4-4-7 O.V.P.

If the auxiliary voltage is higher than zener voltage ZD807 (20 volts) and makes pin 3 of I801 higher than 1 V, pin 6 duty cycle is limited to have the OVP activated.

4-4-8 O.P.P.

The excess current of T802 through R813, R814, R834, C813, R865 and R864 can develop enough voltage on pin 3 then limit the power delivered because the pin 6 duty cycle is limited too.

4-4-9 High Voltage Generation with F.B.T.

1. The H. V generation circuit combines T101 F.B.T. with I101 TL494/KA7500 PWM control circuit.

2. When I101, Vcc(pin12) reaches at 12V, pin 5,6 gets a freerun sawtooth waveform about 25KHz, and approximately 5.7Vp-p, when voltahe at pin 15 is higher than pin 16 (5V reference) then release pin 3 to be controlled by pin 1 feedback signal and compare with pin 5 to output PWM.

3. HFLB1 is used to trigger pin 5 via Q112, to synchronize the deflection circuit.

4. PWM output will drive Q116 & T101 to gererate high voltage (26KV), T101 pin 11, 15 becomes DC/AC feedback, with the voltage link to I101 non-inverting input pin 1 to stabilize H.V (26KV) and VR101 can be adjusted to control H.V value.

5. When X.R.P occur, the hunlock will keep high to pull down I101 pin 2 and shut down PWM output.

4-5 Video Amplifier Section

1. RGB signal inputs are terminated by R501, R531 and R561 then pass through the coupling capacitors C501, C531 and C561 to IC501 LM1267 preamplifier.

2. The amplifier RGB signals (0~4 Vpp) are adjusted by I comes from pin 16 of TDA4841.

3. The video output stages are amplified by I901(LM2465). The RGB cathodes cut off are adjusted by I bus control by internal icon.

C bus from I501, pin 23 is for clamp pulse which

4. Under override condition, CHECK SIGNAL will show up on the screen.

4-6 OSD (On Screen Display) Circuit

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C1996NSL/NST/PNST

1. The I502 NT6827-00002 is OSD IC. The OSD signals are worked by positive vertical pulse from I701 pin

32 that goes through R554 to I502 pin 10, and positive horizontal pulse from HFLB1 through R527 to I502 pin 5. CPU I701 pin 27, 28 (I2C bus) transfers information to I502 pin 7, 8.

2. The OSD R. G. B signals and blanking signal are terminated at I502 pin 15, 14, 13, and 12 feed into I501

pin 1,2,3, and 4, then the OSD picture appears.

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C1996NSL/NST/PNST

5 Alignments and Adjustments

This section of the service manual explains how to make permanent adjustments to the monitor settings.

5-1 General Adjustments

5-1-1 Adjustment Conditions

a) Power Supply

Apply AC 115 V or 220 V

b) Warm-up Time

The monitor must be powered on for 15 minutes before starting any alignment, but requires 30 minutes of warm-up time for convergence adjustment.

c) Signal Input

1. Video: RGB Analog, 0.7 Vp-p, positive

2. Synchronization: Horizontal and vertical TTL signal, separate, positive or negative

3. All adjustments should be made using a signal of FH = 91 kHz, FV = 85 Hz, unless otherwise defined.

5-1-2 Equipment Required

The following equipments are necessary for adjustment procedures:

1. Volt-ohm-A meter (Sanwa FD-750C or equivalent)

2. 30 kV high voltage probe (HP34111A)

3. Oscilloscope (TEK2235 or equivalent)

4. Minolta Color Analyzer II

5. Signal generator (COMPAQ PC with proper display cards or Chroma 2250//2225)

6. Screwdriver

5-1-3 Switching Power Supply and Regulator Adjustment

a. The regulated B+ control has been preset in the factory and needs no adjustment. However, if any repair

is made on the power supply section, the following readjustment procedures are recommended:

1. Allow the monitor to warm-up for about 15 minutes.

2. Apply XGA (1280 x 1024 @ 91 kHz/85 Hz) signal to the monitor.

3. Connect a DC voltage meter to TP001 end, and adjust VR801 for 10.7

4. If a fuse is broken during adjustment, remember to replace it with the exact same type of fuse.

+ 0.1 V DC

b. If necessary, follow the following procedures to enter the factory mode.

1. Press both

2. After turn the power off, monitor will go back to normal mode.

key and 2 key simultaneously then power On.

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5-2 Alignment Procedures

5-2-1 High Voltage Adjustment

CONDITION

Display image : Crosshatch pattern

5-2-2 Screen and White Balance Adjustment

CONDITION

C1996NSL/NST/PNST

Press

and 2 buttons simultaneously when switching the power On.

Display image : No video

PROCEDURE

1 Raster color setting 1-a Adjust HV icon to set high voltage = 26KV. 1-b Adjust G2 icon to set G2 at 600 ± 5V 1-c Set Brightness icon maximum to 40% 1-d Select OSD icon to R.G.B. cutoff 1-e Set G gun cutoff to 0.5 ± 0.15 FL 1-f Adjust R/B cutoff to get x=283 ± 5, y=297 ± 5, Y=0.6 ± 0.2 FL 1-g Set Brightness to cutoff , get Y=0.01 ~ 0.03 FL 1-h Set Brightness to minimum.

CONDITION Display image : 50 mm x 50 mm white block pattern

PROCEDURE

2 6500

K color temperature setting 2-a Set Brightness to cutoff and Contrast to 75 Value 2-b Move cursor on OSD to choose color temperature icon. 2-c Press

key to G gain then adjust G gain = 70 value, then adjust B, R to x=313±5, y=329±5.

2-d Check x=313±5, y=329±5.

3 9300

K color temperature setting 3-a Move cursor on OSD to choose color temperature icon. 3-b. Press

key to G gain then adjust G gain = 75 value, then adjust B, R to x=283±5, y=297±5.

3-c Adjust Contrast max. to set Y=38±2FL 3-d Check x=283±5, y=297±5. 3-e Adjust Contrast min. to set Y=1.0FL. 4 Full white ABL setting

Page 17

Page 20

C1996NSL/NST/PNST

CONDITION

Display image : full white pattern 4-a Set Brightness to cutoff and Contrast to maximum. 4-b Move cursor to choose ABL inside contrast icon. 4-c Adjust ABL to set Y=32±1FL 4-d Repeat all the procedures in 5-2-2 section until the best white balance is obtained.

5-2-3 Focus Adjustment

CONDITION

Display image : e character pattern

PROCEDURE

1. Set Brightness to cutoff and Contrast to maximum.

2. Adjust top VR at T101 (static focus VR) to make vertical line clear.

3. Adjust center VR at T101 (dynamic focus VR) to make horizontal line clear.

4. Repeat above procedures to get best focus.

5-2-4 Dynamic focus Adjustments

1. Horizontal dynamic focus set Hf=370V ±10 V in phase (compare with Vcp signal).

2. Vertical dynamic focus set Vf=145V ±10V in phase.

5-2-5 Static Convergence Adjustments

Static convergence involves alignment of the red, blue and green lines in the center area of the display. Note : The monitor requires 30 minutes warm-up time for convergence adjustment.

CONDITION

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Page 21

Display image : Crosshatch pattern Warm-up Time : 30 minutes

PROCEDURE

1. Set Brightness and Contrast to display a well-defined pattern.

2. Ensure the convergence magnet rings are correctly positioned on the CRT.

Figure 4-1. Convergence Magnets on the CRT

C1996NSL/NST/PNST

CRT

FRONT

8 7 6 5 4 3 2

1) Setup Bolt 2) Bow Magnet 3) Band

5) Spacer 7) Spacer

9) Holder

6) 6-Pole Magnet

4) 4-Pole Magnet

8) 2-Pole Magnet

11) Tabs10) Band

3. Rotate the individual rings of 4-pole convergence magnets by changing the spacing between the 2 tabs to

converge the vertical red and blue lines at the center of the screen.

4. Rotate the pair of rings of 4-pole convergence magnets by maintaining spacing between the 2 tabs to

converge the horizontal red and blue lines at the center of the screen.

5. Rotate the individual rings of 6-pole convergence magnets by changing the spacing between the 2 tabs to

converge the vertical red, blue and green lines.

6. Rotate the pair of rings of 6-pole convergence magnets by maintaining spacing between the 2 tabs to

converge the horizontal red, blue and green lines.

7. Repeat the steps from 3~6 until the best convergence is obtained.

Figure 4-2. 4-pole and 6-pole Magnets Movement

Red/ Bl u e Gre en

6-pole magnets movem e nt

Blue Red

Bl u e Red

Red/ Blue

Green

4-pole magnets movem e nt

Note : The 4-pole magnets and the 6-pole magnets interact, making dot movement complex.

Page 19

Page 22

C1996NSL/NST/PNST

5-2-6 Degaussing

Degaussing is required when poor color impurity appears on the screen. This monitor uses an automatic degaussing circuit that is activated when the power is on. The automatic degaussing will be fully functional again after the monitor has been in operation for 20 minutes.

The degaussing effect is confined to the picture tube since the coils are mounted at the back of the tube. Should any part of the chassis or cabinet becomes magnetized, it is necessary to degauss the affected area with a manual degaussing coil.

5-2-7 Manual Degaussing

1. Apply line voltage to the degaussing coil and move it in a rotary motion over the front, sides, and top of the monitor. The coil should be kept away from the rear of the monitor to avoid damaging the magnetic neck components.

2. Slowly rotate and move the coil away from the monitor to about 6 feet beyond the point where no effect on the CRT will be noticeable.

For proper degaussing, it is essential that the field be gradually reduced by moving the coil slowly away from the monitor. The degaussing coil must never be shut off or disconnected while near the monitor, as this would introduce a strong field instead of canceling the effect of the stray fields.

Page 20

Page 23

6 Troubleshooting

6-1 No Raster

C1996NSL/NST/PNST

No Raster

Measure

voltage of B+ at

T402 pin 2 on

PWB-MAIN

0 V

Short Circuit

at load?

Yes

Check DC B+ line,

Q402, Q404

Check I801,

Q803, R814,

R813, ZD807,

ZD801, R811,

R861, D825

cathode, heater, Grid

Check

AC I/P on

C808

Yes

Normal

(137 V, 91kHz)

Check voltage of

1, Grid 2, etc.

D801,T801,

R804, T804,

High

(175 V or more)

Check I401

Check

F801

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Page 24

6-2 OSD Abnormal

C1996NSL/NST/PNST

OSD Abnormal

Check I502

missing?

Check R516,

R526, R527

OK?

Yes

Check J516,

R556 OK?

Yes

Put on

I502

Replace them

Replace it

Page 22

Replace I502

Page 25

6-3 Function Key Abnormal

Function Key Abnormal

C1996NSL/NST/PNST

Check I701 and

I703 missing?

Power

ON/OFF again and

check X701, oscillator

OK?

Yes

Check

I703 EEPROM content

OK?

Yes

Put on

I701, I703

Replace X701

Replace I703 or do

ATE again

Replace I701 and check

uP OK?

Check

pin 5 of I701

is 5V?

Replace I705

Yes

Replace I701

Check

R732, C713

Page 23

Page 26

6-4 No Vertical Scan (Raster is one horizontal line)

No Vertical Scan

Check

I301 voltage of

pin 1 is 12V, pin

2 is 37V and

pin 4 is

-14V?

Yes

C1996NSL/NST/PNST

Check or replace

I301.

Check

pin 5 O/P waveform

at I301

Normal

Check

pin 6, 7 of I301

waveform

Still no vertical scan

Check or replace CRT

Abnormal

Replace I301

Page 24

Page 27

6-5 Out of Horizontal Synchronization

Out of Horizontal

Synchronization

C1996NSL/NST/PNST

Horizontal sync present at pin 15 of I401

Yes

Check

I401 pin 8 H output

frequency

Yes

Check Q401, T401, Q402, R402, R403,

C404, R404, D402, Q410

6-6 Out of Vertical Synchronization

Out of Vertical

Synchronization

Ckeck or replace

the signal cable or

I701

Check or replace

the signal cable

or I701

Vertical sync

present at

pin 14 of I401

Yes

Check

I401 pin 24 ramp

frequency

Check C442

Ckeck signal cable &

vertical sync input &

I701

Page 25

Page 28

6-7 R.G.B. Video Amplifier Abnormal

RGB Video AMP Abnormal

C1996NSL/NST/PNST

Check

waveform at I501 pin 18, 19

and 20

Yes

Check

I901 pin 1, 3 and 2 voltage

and wave form

Yes

Video signal present at the

pin of the CRT R.G.B.

Cathode

Yes

Check or replace the

signal cable or I501

Replace I901

Defective cut-off circuit

(DC restore)

6-8 Blank EEPROM Trouble-shooting:

Description of functions for models under C1996 series EEPROM DATA AUTO-RELOAD

The function allows plant staff to pre-write and customer service personnel to use blank EEPROM through the pre-write EEPROM function whenever the CPU is implemented. The method of operation is as follows:

First, press the HOT KEY, start after C1996 turns to (<&>) KEY. At this point of time, the CPU is capable of detecting the first 8 DATA of each page that EEPROM contains. When the reading goes to 00H or FFH, the EEPROM PAGE will turn to blank; instead, the pre-set value is being written into the EEPROM through CPU. Otherwise, it shall be deemed an effective value and that the pre-write function shall not be activated.

Page 26

Page 29

C1996NSL/NST/PNST

7 Recommended Parts List

Note:1. The components identified by   mark are critical for X-ray safety. Replace these with

exactly the same parts specified.

2 . There is only OTP IC at the model beginning (FPR stage or before). When it put in mass

production and there must be Mask coming out. Please check BOM to get the last release part number and related information.

No. Location Part Number Description

1 C407 6325943252-03 P=22.5 PPS 4300P 1800V

2 C808 6312633126 ALU uF 330 400V F 85C 25x40

3 D801 6417001000 TS4B05G-01

12 I802 6442014000 IC LTV-817D

13 T404 6139000500 XFRMER H-CENT THC1005 5mH

D814 D815 D402

D407 D817 D119

D831 D813 6412002937 DIODE FUF 5407AMP 3A/800V

F801 6851504053 / 51 FUSE TIME LAG 5ST4 4A/250V

I301 6442026400 IC TDA4863 9P (PHILIPS)

***

I401 6442030000 IC TDA4841 32P SDIP (PHILIPS)

I501 6442031500 IC LM1267

I701 6448017800 IC NT68P65AU 42P PDIP NOVATEK(FLASH)

Q402 6421004310 TR NPN 2SC5411 (TOSHIBA)

***

Q404 6427000900 FET P-CHNL SFS9634

***

6412020007 DIODE SF34 3A/200V

6412014707 PUP5406

17 Q115 6426006400 FET N-CHNL IRFS630A SAMSUNG

19 R803 6203459017 POSISTOR 4.5 OHM Q 2PINPITCH=10

20 R804 6201100062 THERMISTOR 10 OHM 5A P=7.5 TKS

22 T401 6135003400 XFRMR HOR DRIVE THD-1034 EI19

Q116 6426005410 FET N-CHNL IRFS840A

***

Q803 6426009600 FET N-CHNL 2SK2996 TOSHIBA

***

R818 6422002925 FS OHM 0.27 1W J HOR

***

Page 27

Page 30

C1996NSL/NST/PNST

No.

23 T101 6133093010 FBT TFB-9301 FM159R-B

24 T402 6111444130 COIL CHOKE 4.4MH

25 T801 6138002201 LINE FILTER TLF-1016A 16mHET28

26 T802 6131052500/510 XFRMER PWR TPW-1087 EE40

27 X701 6449006900 CRYSTAL 12MHz TOP8.000 30pF TOP

28 ** I901 6442032300 LM2465 9P

29 I402 6442005900 LM324 14P

30 *** I801 6442006720 KA3843B

31 I301 6442026400 IC TDA4863 9P (PHILIPS)

32 R813 6221215852 0.15 OHM 2W

33 ** I703 6448015720 MICRO CHIP IC 24LC08B-8P

34 D818 6412019907 SF24

Location Part Number Description

36 C413 632627456-03 MPP 0.27U 250V TAI PMS

37 C421 6326210453-03 MPP 0.1u 250v TAI PMS

38 C423 6326322443 MPP 0.22u 250V HJC

39 C425 6326262442 MPP 0.62u 250V HJC

40 C427 6326215542 MPP 1.5u 250V HJC

41 V901 6811192608 M46QCE261X112 SAMSUNG

Q406 Q410 Q403

6421003800 KSD882

Page 28

Page 31

8 Block Diagram

ABL

I502

NT6827

OSD

HFLB1

VTTL

CLBL

SCL1 SDA1

HFLB1

Blanking

Q541 Q542

P501

B-IN

R-IN

G-IN

LM1267

VIDEO PREAMP

CLBL

RGB

LM2465

RGB

CUT OFF

ADJUST

Q901 Q902 Q931 Q932 Q961 Q962 Q903 Q933 Q963

HEATER

C1996NSL/NST/PNST

R G B

G1 G2

FOCUS 2

FOCUS 1

P502

P702

SCL SDA

DDC 5V

LED

CLBL

HFLB

SDA 1

SCL 1

O/R

SCL

SDA

V SYNC

H SYNC

KEY

CONTROL

VTTL

HFLB1

6.3V

G2 CONTROL

I701

NT6861 AU

VIDEO 5V

GENERATOR

VTTL

HTTL

SCL1

SDA1

OFF

CLBL

GND

10.7V

80V

I401

TDA 4841

10.7V

180V

D. FOCUS

VOUT 1

VOUT 2

XRP

P505

I101

PWM CONTROL

TL494/KA7500

HFLB1

H DRIVER

Q402 D403 C407

B+

DRIVER

Q404 T402

180V

Q116 FBT

DRIVER

Q115

CANCELING

CKT

80V

LINEARITY

CONTROL

T403

H CENTER

Q403

VR401

T101

FBT

T102

-H

-V

200V

48V

G2 CONTROL

CONTROL CKT Q105

Horizontal

Dynamic focus

XRP CKT

C137 R132

ABL

P301

DYNAMIC

P801

D701

4.3V

D703

SCL1

SDA1

I705

13V

LINE

FILTER

Q807

BRIDGE

DIODE

E2PROM

LOW VOLTAGE

DROP DOWN

I703 2404

DEG CKT

I801

SMPS

VERTICAL

O/P I301

TDA4863

-14V

POWER

O/P

T802

-14V

80V

180V

10.7V

13V

37V

10.7V

SWITCH

Q813

10.7V

Page 29

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Page 33

Page 34

Page 35

Page 36

Page 37

LITE-ON TECHNOLOGY CORP.

5 F, No. 16, Sec. 4, Nanking E. Road, Taipei, Taiwan

Tel: 886-2-25706999Fax: 886-2-25706888

URL:// www.liteontc.com

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