Tatung VM9G5DA S995T User manual

COLOUR MONITOR
FLAT SCREEN
VM9G5DA S995T
Service Information

TABLE OF CONTENTS
PAGE
1. SPECIFICATIONS .................................................................................................... 3-4
2. PRECAUTION AND NOTICES ................................................................................ 5
2-1 SAFETY PRECAUTIONS .............................................................................. 5
2-2 PRODUCT SAFETY NOTICE ....................................................................... 5
2-3 SERVICE NOTES ........................................................................................... 5
2-4 HIGH VOLTAGE WARNING ....................................................................... 6
3. OPERATING INSTRUCTIONS ................................................................................ 6-7
4. ADJUSTMENT ......................................................................................................... 7
4-1 ADJUSTMENT CONDITIONS AND PRECAUTIONS ............................... 7
4-2 MAIN ADJUSTMENTS ................................................................................. 7
4-3 ADJUSTMENT METHOD ............................................................................. 7-10
5. CIRCUIT DESCRIPTION ......................................................................................... 11
5-1 MICRO CONTROLLER CIRCUIT ............................................................... 11
5-2 DEFLECTION CIRCUIT ......…….................................................................. 12
5-3 VIDEO CIRCUIT ............................................................................................ 12
5-4 POWER SUPPLY .....……………………....................................................... 12
5-5 TRANSISTOR & DIODE CIRCUIT .....……………….................................. 13-15
6. TROUBLE SHOOTING CHART .............................................................................. 16
6-1 NO RASTER, CRT RELATIVE CIRCUIT PROBLEMS .............................. 16
6-2 ABNORMAL DISPLAY ................................................................................. 17
6-3 NO BLANKING .............................................................................................. 18
6-4 HOR. /OSC /DEF /HV CIRCUIT FAULT ...................................................... 18
6-5 ABNORMAL DDC (PLUG & PLAY) ...........…………................................. 19
6-6 ABNORMAL HORIZONTAL DEFLECTION .............................................. 19
6-7 ABNORMAL VERTICAL SCANNING ........................................................ 20
6-8 SIDE-PIN CUSHION DISTORTION ............................................................. 20
6-9 POOR FOCUS ................................................................................................ 20
6-10 NO SOUND (OPTION FOR AUDIO MODEL ONLY).........….................... 21
6-11 ABNORMAL VIDEO LEVEL ON SCREEN................................................. 21
6-12 POWER SUPPLY TROUBLE SHOOTING CHART ..................................... 22
7. MECHANICAL OF CABINET FRONT DIS-ASSEMBLY...................................... 23
8. PARTS LISTING .........................................................................................…............ 24
9. BLOCK DIAGRAM .................................................................................................. 45-46
10. IC BLOCK DIAGRAMS............................................................................................ 47-49
11. PCB LAYOUT .......................................................................................................... 50-51
12. SCHEMATIC DIAGRAM ......................................................................................... 52

1. SPECIFICATIONS
1. CRT
48.3 CM(19") 90degree Deflection, 29mm Neck, 0.26mm Dot Pitch, Non-Glare Screen,anti-reflective,antistate
coating
2. Viewable image Size : 45.7CM (18") diagonal
3. Display Color: Unlimited Colors
4. External Controls:
Power On/Off, OSD key, Function knob: Contrast, Brightness, H-Size, H-Center, V-Size, V-Center, ZOOM, Pincushion,
Trapezoid, Pin-Balance, Parallelogram, Rotation, Moire Reduce, Recall, Degaussing, Color Temperature, Volume
(Option).
5. Input Video Signal
Mode 1 Mode 2 Mode 3 Mode 4
RGB Analog RGB Analog RGB Analog RGB Analog
Horiz. Sync: TTL Level TTL Level TTL Level TTL Level
Negative Negative Positive Positive
Vert. Sync: TTL Level TTL Level TTL Level TTL Level
Negative Positive Positive Positive
Horizontal: 640 (H) 720 (H) 800 (H) 1024 (H)
Vertical : 480 (V) 400 (V) 600(V) 768 (V)
Fh (KHz): 31.47 31.47 46.875 60.02
Fv (Hz) : 60 70 75 75
Mode 5 Mode 6 Mode 7 Mode 8
RGB Analog RGB Analog RGB Analog RGB Analog
Horiz. Sync: TTL Level TTL Level TTL Level TTL Level
Positive Positive Positive Positive
Vert. Sync: TTL Level TTL Level TTL Level TTL Level
Positive Positive Positive Positive
Horizontal: 1024 (H) 1280 (H) 1280 (H) 1600 (H)
Vertical : 768 (V) 1024 (V) 1024 (V) 1200 (V)
Fh (KHz) : 68.6 79.97 91.15 93.75
Fv (Hz) : 85 75 85 75
6. Display Size
Horizontal: 346 mm
Vertical: 260 mm
7. Scanning Frequencies
Horizontal: 30KHz ~95KHz
Vertical: 50 Hz ~150 Hz

8. Factory Preset Timings: 8
User Timings: 20
9. Misconvergence
Center : 0.25mm Max.
Corner : 0.35 mm Max.
10. Video Dot Rate: 200 MHz
11. Power Source:
Switching Mode Power Supply
AC 100 ~240V, 50/60Hz Universal Type
12. Operating Temperature: 0°C to 40°C Ambient
13. Humidity:
10%to 85%Relative, Non-Condensing
14. Weight: 20.0 Kgs(Net), 24.0Kgs(Gross)
21.8 Kgs(Net), 24.8Kgs(Gross) (for Audio model)
15. Dimensions Monitor:
Carton: 574(W) x 537(H) x 594(D) mm
Monitor: 460(W) x 466(H) x 470(D) mm
460(W) x 503(H) x 470(D) mm (for Audio model)
16. External Connection:
15 Pin D-type Connector
AC Power Cord
17. Speaker: (Option)
Rate power: 5W (per channel)
Impedance: 16Ω
18. Regulations: UL, CSA, FDA, FCC, TÜV/GS, and CE, MPR-II
TCO'95 or TCO'99(Option)

2. PRECAUTIONS AND NOTICES
2-1 SAFETY PRECAUTIONS
1. Observe all caution and safety related notes located inside the display cabinet.
2. Operation of the display with the cover removed, may cause a serious shock hazard from the display power supply.
Work on the display should not be attempted by anyone who is not thoroughly familiar with precautions necessary
when working on high voltage equipment.
3. Do not install, remove or handle the picture tube in any manner unless shatter-proof goggles are worn. People who are
not so equipped should be kept away while handling picture tube. Keep picture tube away from the body while
handling.
4. The picture tube is constructed to limit X-RAY radiation to 0.5 mR/HR. For continued protection, use the designated
replacement tube only, and adjust the voltages so that the designated maximum rating at the anode will not be
exceeded.
5. Before returning a serviced display to the customer, a thorough safety test must be performed to verify that the display
is safe to operate without danger or shock. Always perform an AC leakage current check on the exposed metallic parts
of the cabinet, such as screw heads.
Test method for current leakage is described as follow.
(a) Plug the AC line cord directly into rated AC outlet (do not use a line isolation transformer during this check).
(b) Use an AC voltmeter having 5000 ohms per volt or with more sensitivity in the following manner: Connect a
1500 ohms 10 Watt resistor, paralleled by a 0.15UF, AC type capacitor between a known good earth ground
(water pipe, conduit, etc.) and the exposed metallic parts simultaneously. Measure the AC voltage across the
combination of 1500 ohms resistor and 0.15UF capacitor.
(c) Reverse the AC plug at the AC outlet and repeat AC voltage measurements for each exposed metallic part.
(d) Voltage measured must not exceed 0.5 volts RMS. This corresponds to 0.35 milliamp AC. Any value exceeding
this limit constitutes a potential shock hazard and must be corrected immediately.
2-2 PRODUCT SAFETY NOTICE
Many electrical and mechanical parts in this chassis have special safety visual inspections and the protection afforded by
them cannot necessarily be obtained by using replacement components rated for higher voltage, wattage, etc. Before
replacing any of these components read the parts list in this manual carefully. The use of substitute replacement parts,
which do not have the same safety characteristics, as specified in the parts list may create shock, fire, X-RAY radiation or
other hazards.
2-3 SERVICE NOTES
1. When replacing parts or circuit boards, clamp the lead wires around terminals before soldering.
2. When replacing a high wattage resistor (more than 1/2W of metal oxide film resistor) in circuit board, keep the resistor
about 10mm (1/2 in) away from circuit board.
3. Keep wires away from high voltage or high temperature components.
4. Keep wires in their original position so as to reduce interference.

2-4 HIGH VOLTAGE WARNING
Operation of monitor outside of cabinet or with back removed may cause a serious shock hazard. Work on this model
should only be performed by those who are thoroughly familiar with precautions necessary when working on high voltage
equipment.
Exercise care when servicing this chassis with power applied. Many B plus and high voltage terminals are exposed which,
if carelessly contacted, can cause serious shock or result in damage to the chassis. Maintain interconnecting ground lead
connections between chassis and picture tube dag when operating chassis.
Certain HV failures can increase X-ray radiation. Monitor should not be operated with HV levels exceeding the specified
rating for the chassis type. The maximum operating HV specified for the chassis used in this monitor is
26.5KV ±1KV
With a line voltage of 120/240 VAC. Higher voltage may also increase possibility of failure in HV supply.
It is important to maintain specified values of all components in the horizontal and high voltage circuits and anywhere else
in the monitor that could cause a rise in high voltage or operating supply voltages. No changes should be made to the
original design of the monitor. Components shown in the shaded areas on the schematic should be replaced with exact
factory replacement parts. The use of unauthorized substitute parts may create a shock, fire or other hazard.
To determine the presence of high voltage, use accurate, high impedance, HV meter connected between second anode lead
and CRT dag grounding device. When servicing the High Voltage System, remove static charge from it by connecting a
10K-ohm resistor in series with an insulated wire (such as a test probe) between picture tube dag and 2nd anode lead. (AC
line cord disconnected from AC power outlet.)
The picture tube used in this monitor employs integral implosion protection. Replace with tube of the same type number
for continue safety. Do not lift picture tube by the neck. Handle the picture tube only after discharging the high voltage
completely.
3. OPERATING INSTRUCTIONS
This procedure gives you instructions for installing and using the color display.
1. Position the display on the desired operation and plug the power cord into a convenient AC outlet. Three-wire power
cord must be shielded and is provided as a safety precaution as it connects the chassis and cabinet to the electrical
conduit ground. If the AC outlet in your location does not have provisions for the grounded type plug, the installer
should attach the proper adapter to ensure a safe ground potential.
2. Connect the 15-pin color display shielded signal cable to your signal system device and lock both screws on the
connector to ensure firm grounding. The connector information is as follow:
3.
1
6
11 15
5
10
15 - Pin Color Display Signal Cable

PIN NO. DESCRIPTION PIN NO. DESCRIPTION
1. RED 9. NC
2. GREEN 10. GND
3. BLUE 11. SYNC. GND
4. GND 12. SDA
5. GND 13. HORIZ. SYNC
6. GND-R 14. VERT. SYNC (•VCLK)
7. GND-G 15. SCL
8. GND-B
3. Apply power to the display by turning the power switch to the "ON" position and allow about thirty seconds for display
tube warm-up. The Power-On indicator lights when the display is on.
4. With proper signals feed to the display, a pattern or data should appear on the screen, adjust the brightness and contrast
to the most pleasing display.
5. This monitor has power saving function following the VESA DPMS. Be sure to connect the signal cable to the PC.
6. If your color display requires service, it must be returned with the power cord.
4. ADJUSTMENT
4-1 ADJUSTMENT CONDITIONS AND PRECAUTIONS
1. Approximately 30 minutes should be allowed for warm up before proceeding.
2. Adjustments should be undertaken only on those necessary elements since most of them have been carefully preset at
the factory.
4-2 MAIN ADJUSTMENTS
NO.
FUNCTION LOCATION DESIGNATION
1. 54V ADJ PCB - MAIN VR902
2. HIGH VOLTAGE ADJ PCB - MAIN VR801
3. SCREEN ADJ FLY BACK TRANS T802
4. FOCUS ADJ FLY BACK TRANS T802
5. ABL ADJ PCB - MAIN VR401
6. SUB BRIGHTNESS ADJ PCB - MAIN VR403
7. SHUTTLE KNOB KEY - BOARD SW103
4-3 ADJUSTMENT METHOD
1. B + & HV voltage adjustment:
A. Chrome-2000 Signal generator or PC equivalent set mode 7, VGA 1024 x768 pattern 1.0.
B. Connect a DC Volt meter between TP 904 and ground, then adjust VR902 to be 54.0 VDC.
C. Connect a DC Volt meter with HV probe 1000: 1 between CRT Anode and ground, Then adjust VR801 to be
26.5KV.
D. Connect a DC Volt meter between TP401 (G1) and ground, Brightness set to 50. Then adjust VR403 to be –
35VDC.

2. Factory preset Timings Adjustment:
A.Press shuttle Knob to show OSD window press shuttle Knob again to switch the functional controls.
B.Rotate the shuttle Knob to select the "ZOOM" function, then press the shuttle Knob 10 seconds again. While do not
release the shuttle Knob until the OSD window changed to the Factory preset window.
C. The Factory preset window contains the following functional controls. Select one of the control. Then press the
shuttle knob to adjust its value for the optimum picture.
80
RGB
RGB
EXIT
FACTORY PRESET
6500
9300
H-SIZE CB CORNER BOTTOM G-GAIN
H-CENTER V-C LINEARITY B-GAIN
V-SIZE V-S LINEARITY R-BIAS
VS V-SUB SIZE ROTATION G-BIAS
V-CENTER H-MOIRE REDUCE G-BIAS
VC V-SUB CENTER V-MOIRE REDUCE 9300 COLOR TEMPERATURE
PINCUSHION DEGAUSS
TRAPEZOID 6500 COLOR TEMPERATURE
PARALLELOGRAM CONTRAST RETURN
PIN-BALANCE BRIGHTNESS OSD EXIT
CT CORNER TOP R-GAIN
D.While the all adjustments are finished, please select the " EXIT " function, and press the shuttle knob to Quit the
OSD window.
E. To switches the input signal to the other Timing Mode. Please follow step C ~ D to get the optimum picture.
F. Select the " " RETURN function and press the shuttle knob, then the Factor Preset window will be returned
to the original OSD window.(user's operation condition)

G. The setting data of the CONTRAST, BRIGHTNESS, PIN-BALANCE, PARALLELOGRAM, ROTATION,
COLOR TEMPERATURE are common mode saved in the memory. Don't needed adjust it individual at every
timing Mode and save in the memory.
3. White Balance, Luminance adjustment:
A.Bias (Low Luminance) adjustment:
(a) Set mode 7 1024 x768 Fh: 60KHz full white pattern.
(b) To make the adjustment condition is under the Factory preset window.
Same as step 2-C.
(c) Warm up more than 30 minutes.
(d) Brightness set to maximum. Contrast set to min. raster pattern, then adjust FBT screen VR to make
Y=1.0FL ±0.2FL
(e) Set G-Bias to make the setting value about 56, then adjust the R. B Bias individual to the color
temperature x= 283 ±10, y= 297 ±10.
(f) Readjust screen VR to y=1.0FL ±0.2FL
B. Gain (High light) adjustment:
(a) Set mode 7 1024 x768 Fh: 60KHz full white pattern.
(b) Brightness set to raster just cutoff and set the contrast to max.
(c) Adjust G-Gain , B-Gain , R-Gain , to make color temperature x=283±10, y=297±10.
C.Recheck item A&B to make sure both of them in spec. Finally select OSD function to the 9300°K function, then
press the shuttle knob. To make the setting data saved in the memory.
D.The adjustment of 6500°K white Balance, May follow step item B , with the x=313±10, y=329±10.
E. Full white luminance:
(a) Set mode 7 1024 x768 Fh: 60K full white pattern.
(b) Image Size : H:346±4mm V:260±4mm.
(c) Contrast set to max, Brightness set to cut off.
(d) Adjust VR401 to the luminance at 28 FL ±1FL.
4. Focus Adjustment:
A. Set mode 7 1024 x768 Fh: 60KHz with character full page.
B. Adjust brightness to center and contrast to max.
C.Then adjust focus VR1 to a fine vertical line.
D.Adjust focus VR2 to a fine horizontal line.
E. Repeat step C & D.to make the display focus performance very well.

5. Purity Adjustment:
A. Be sure that the display is not being exposed to any external magnetic fields..
B. Ensure that the spacing between the Purity, Convergence, Magnet, (PCM), assembly and the CRT stem is 29mm
.(See below diagram)
C. Produce a complete, red pattern on the display. Adjust the purity magnet rings on the PCM assembly to obtain a
complete field of the color red. This is done by moving the two tabs in such a manner that they advance in an
opposite direction but at the same time to obtain the same angle between the two tabs, which should be
approximately 180°.
D. Check the complete blue and complete green patterns to observe their respective color purity. Make minor
adjustments if needed.
RELATIVE PLACEMENT OF TYPICAL COMPONENTS
Purity Magnets
Deflection Yoke
4-pole Convergence Magnets
6-pole Convergence Magnets
6. Convergence adjustment:
A.Produce a magenta crosshatch on the display.
B.Adjust the focus for the best overall focus on the display.
Also adjust the brightness to the desired condition.
C.Vertical red and blue lines are converged by varying the angle between the two tabs of the 4 pole magnets on the
PCM assembly. (See above diagrams)
D.Horizontal red and blue lines are converged by varying the two tabs together, keeping the angle between them
constant.
E. Produce a white crosshatch pattern on the display.
F. Vertical green and magenta lines are converged by varying the angle between the two tabs of the 6-pole magnets.
G.Horizontal green and magenta lines are converged by varying the two tabs together, keeping the angle between them
constant.