Daewoo 902D, 904DF, 903Ds Service Manual

DAEWOO ELECTRONICS CO., LTD.

Service Manual

XGA COLOR MONITOR

Model : 902D/903Ds/904DF

◆ Power IC, Transistor or Devices Removal/Replacement

1. Heat and remove all solders from the device leads.

2. Remove the heatsink mounting screw (if applicable).

3. Carefully remove the device from the circuit board.

4. Insert new device in circuit board.

5. Solder each device lead and then clip off excess lead.

6. Replace heatsink.

◆ Diode Removal/Replacement

1. Remove defective diode by clipping its leads as close as possible to diode body.

2. Bend the two remaining leads perpendicularly to the circuit board.

3. Observing diode polarity, wrap each lead out of the new diode around the corresponding lead on the circuit board.

4. Securely crimp each connection and solder it.

5. Inspect the solder joints of the two “original” leads on the circuit board copper side. If they are not shiny, reheat them and apply additional solder if necessary.

TECHNICAL INFORMATION

CDT Size 19-inch 19-inch 19-inch

short length DynaFlat Diagonal visible image area 18-inch Dot Pitch 0.26 mm 0.25 mm Synchronization Horizontal 30 - 95 KHz

Vertical 50 - 160 Hz Plug and Play DDC1/2B/CI Power Saving EPA, VESA DPMS, Nutek Compliant Power Source 100-240 Vac, 50/60Hz (Free Voltage) Power Consumption 120 W Dimension(mm) 466(W) 466(W) 466(W) (set with stand) 475.5(H) 475.5(H) 475.5(H)

464.5(D) 408.5(D) 465(D) Weight-unpacked(lbs/Kg) 51.8/23.5 44.0/20.0 56.2/25.5 Operating Temperature 10 ~ 40°C /50 ~ 104°F

Model Names 902D 903Ds 904DF

ADJ Adjustment AFC Automatic Frequency Control CRT Cathode Ray Tube Def Deflection D.Y Deflection Yoke FBT Flyback Transformer H.SYNC Horizontal Synchronization OSC Oscillator P.S.U Power Supply Unit PWA Printed Circuit Board Wiring Assembly R.G.B Red, Green, Blue V.Sync Vertical Synchronization

GENERAL INFORMATION

This color monitor automatically scans all horizontal frequencies from 30KHz to 95KHz, and all vertical frequencies from 50Hz to 160Hz. This color monitor supports IBM PC, PC/XT, PC/AT, personal System/2 (PS/2), Apple Macintosh, and compatible users crisp text and vivid color graphics display when using the following graphics adapters : (VGA, 8514/A, Super VGA, VESA and XGA and Apple Macintosh Video Card). And so, this color monitor has a maximum horizontal resolution of 1600 dots and a maximum vertical resolution of 1200 lines for superior clarity of display. By accepting analog signal inputs which level is zero to 0.7 Volts. This color monitor can display and unlimited palette of colors depending on the graphics adapter and software being used.

◆ Abbreviations

Pin Signal

1 Red 2 Green 3 Blue 4 GND 5 GND 6 GND - Red 7 GND - Green 8 GND - Blue 9 +5Vdc 10 GND - H.Sync 11 GND - V.Sync 12 Bi-directional Data (SDA) 13 Horizontal Sync 14 Vertical Sync (VCLK) 15 Data Clock (SCL)

• Degaussing is always required when adjusting purity or convergence.

• The white balance adjustment has been done by a color analyzer in factroy. The adjustment procedure, described in the service manual is made by a visual check.

• Allow 20 minutes warm-up time for the display before checking or adjusting only electrical specification or function.

• Reform the leadwire after any repair work.

◆ Caution For Servicing

• In case of servicing or replacing CRT, high voltage sometimes remains in the anode of the CRT. Completely discharge

high voltage before servicing or replacing CRT to prevent a shock to the serviceman.

Arrangement of 15-pin D-sub connector

PIN CONNECTOR

CAUTIONS FOR ADJUSTMENT AND REP AIR

OPERATION AND ADJUSTMENT

Control Panel

• Move cursor to the right window on the OSD window.

• Increase the value of any selected function.

• Move cursor to the left window on the OSD window.

• Decrease the value of any selected function.

• Launch OSD(On-Screen Display) MENU window.

• Move cursor to the high window on the OSD window.

• Increase the value of V.size or V.center.

• Move cursor to the low window on the OSD window.

• Decrease the value of V.size or V.center.

Key Process

•

When you choose the icon on the OSD window, you can exit the OSD screen.

Hot Key

BRIGHTNESS CONTRAST

DEUTSCH

ENGL SH

ESPAÑOL FRANCA S

TAL ANO

Start

OSD Functions

ICON CONTROL FUNCTIONS

LANGUAGE

H. CENTER &

V. CENTER

COLOR TEMP

RED GAIN

GREEN GAIN

BLUE GAIN

RED BIAS

GREEN BIAS

Select language for OSD (5 languages).

Adjust the position of the display horizontally(left or right) and vertically (up or down).

Choose different preset color temperatures or set your own customized color parameters.

Adjust the red gain.

Adjust the green gain.

Adjust the blue gain.

Adjust the red bias.

Adjust the green bias.

BLUE BIAS

H. SIZE &

V. SIZE

H. LINEARITY

V. LINEARITY

H. MOIRE

V. MOIRE

FOCUS

Adjust the blue bias.

Adjust the width (horizontal size) and the height (vertical size) of the display.

Adjust the horizontal linearity.

Adjust the vertical linearity.

Adjust the horizontal picture moire cancellation.

Adjust the vertical picture moire cancellation.

Adjust the focus image.

ZOOM

Adjust the display width & height at the same time.

ICON CONTROL FUNCTIONS

PINCUSHION

TRAPEZOID

PIN BALANCE

PARALLELOGRAM

PIN S Control

PIN W Control

ROTATION

Adjust the left and right margins for more convex or more concave margins.

Adjust the trapezoid of the screen by moving the lines inward or outward.

Adjust the side balance when the sides of the screen are bowed towards left or right.

Adjust the parallelogram when the screen is leaning left or right.

Adjust the pin S control when the sides of the screen are in a S shape.

Adjust the pin W control when the sides of the screen are in a W shape.

Adjust the rotation when the screen is tilted left or right.

DEGAUSS

STATUS

POWER SAVER

TEST PATTERN

RECALL

Degauss the display and restore image quality.

Display horizontal & vertical frequency and polarity.

YES : VESA DPMS operation. NO : NO DPMS operation.

Display a RGB Color Bar to determine whether the screen color is expressed normally or not.

Reset the screen to the Factory Preset Display Settings.

◆

Standard Adjustment Conditions

1. Power source voltage : AC 100 - 240Vac, 50/60Hz.

2. Aging : Take at least 15 minutes warm-up time.

3. Signals. Video : Analog 0.7Vpp 75W terminal positive polarity Synchronizing : Composite H+V Sync : 1.0Vpp ~ 5.0Vpp (Positive / Negative)

Separate H, V Sync : TTL Level (Positive / Negative)

Deflection frequency

Horizontal Frequency : 30KHz - 95KHz Vertical Frequency : 50Hz - 160Hz

◆ Pre-Adjustment

1. HV Adjustment Adjust VR151 for 26KV(902D, 904DF) / 26.5KV(903Ds) at 91KHz mode.

◆ Main Adjustment

1. Setting the Controls Set contrast and brightness in Control Menu unless otherwise specified.

Contrast : Max. Brightness : Center

2. H.size, H.phase, V.size, H.phase, Side Pincushion, Pincushion S, Pincushion W, Trapezoid, Parallelogram, Rotation, Pin Balance, H.Linearity, V.Linearity

Receive the cross hatch pattern of Factory preset mode. H.size, H.phase, V.size, H.phase, Side Pincushion, Pincushion S, Pincushion W, Trapezoid, Parallelogram, Rotation, Pin Balance, H.Linearity, V.Linearity controls are adjusted at each mode. In Factory, Auto Alignment was done at each mode. Therefore, Factory preset mode have their own value according to each control.

3. Focus

(a) Set brightness control to center and contrast control to Maximum. (b) Receive all “H” character pattern of 91KHz mode signal. (c) Adjust the Static Focus VR to obtain best H.Focus. (d) Adjust the Dynamic Focus VR to obtain best V.Focus. (e) If the H/V Focus is not satisfactory, readjust the Static / Dynamic Focus.

4. White Balance Adjustment

(a) Select 9300°K on the OSD Menu. (b) Receive a full white pattern of 91KHz mode signal by using the signal generator. (c) Set the brightness control to 60 and the contrast control to maximum. (d) Cut off the FBT screen VR. (e) Receive all the black patterns. The luminance of the screen should be 0.2 ± 0.03 Ft-L by using

Screen VR.

(f) Select the R-BIAS, G-BIAS and B-BIAS on the control menu and adjust the / key to get the

color coordinates in x=0.281 ± 0.015, y=0.311± 0.015. (g) Receive a small block pattern. Adjust the brightness value to the center. (h) Select the R-GAIN and B-GAIN and adjust the / key to get the color coordinates in x=0.281 ±

0.015, y=0.311 ± 0.015.

(i) Adjust the ABL(at the OSD) control to get the screen luminance to 37 Ft/L (a small block pattern).

(j) Receive a full white pattern. Adjust VR201(Sub-contrast) to get the screen luminance to 27 Ft-L.

Check if the x, y coordinates of color analyzer is in x=0.281±0.015, y=0.311±0.015. If the color coordinates is out of range, adjust the R. G. B BIAS & GAIN to get the coorinates in x=0.281, y=0.311. Make sure that the coordinates is in the appropriate range.

ALIGNMENT PROCEDURE

(k) Select 6550°K on the OSD Menu and set the color coordinates in x=0.313, y=0.329 at the

maximum contrast control and center brightness control

(l) Check if a full white pattern is over 27Ft/L.

5. Static Convergence Adjustment (a) Apply a magenta cross hatch pattern on display. (b) Adjust the focus from the best over all focus on the display.

Also adjust the brightness to the desired condition.

magnets.

(d) Horizontal red and blue lines are converged by varying the tabs together and keeping the angle

between them constant. (e) Apply a yellow cross hatch pattern on the display. (f) Vertical green and red lines are converged by barying the angle between the two tabs of the 6-pole

magnets.

(g) Horizontal green and red lines are converged by varying the tabs together and keeping the angle

between them constant.