Tatung G5GS Series User manual

MODEL:C5GS
SERIES
Low Radiation Extended VGA
PLUG & PLAY COLOUR MONITOR
SERVICE MANUAL

2
TABLE OF CONTENTS
PAGE
1. Precaution and Notices ....................................................................................... 1
2. Specifications ....................................................................................................... 3
3. Control Location and Functions ....................................................................... 5
4. Disassembly Instructions ................................................................................... 7
5. General Connection & Applications ................................................................. 9
6. Electronic Circuit Description ......................................................................... 10
7. Adjustment ........................................................................................................ 19
8. Troubleshooting Flow Chart ............................................................................ 22
9. Block Diagram .................................................................................................. 28
10. PCB Layout ....................................................................................................... 29
11. Circuit Diagram ................................................................................................ 30
12. Electrical Parts List .......................................................................................... 31
13. Mechanical Disassembly .................................................................................. 45
14. Mechanical Parts List ....................................................................................... 46

1
1. Precautions and Notices
1.1 Safety Precautions
1) Observe all cautions and safety related notes located inside the display cabinet and on the display
chassis.
2) Operation of these displays outside the cabinet or with the cover removed involves a shock hazard
from the display power supplies. 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 not equipped should be kept away while handling picture tube.
4) The picture tube is constructed to limit X-RADIATION to 0.5mR/HR at 300 microamperes anode
current. For continued protection, use the recommended replacement tube only, and adjust the
voltage so that the designated maximum rating at the anode will not be exceeded.
5) Before returning a serviced display to the customer, a thorough safely 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. Proceed as follows :
Connect the monitor power lead to the mains supply, via an isolation transformer, and switch on.
Using the test circuit shown in Fig.1-1, measure the AC leakage current between each pole ( L
and N) of the supply and all accessible metal parts. The earth leakage current must not exceed 3.5
mA.
L
Mains N
Input E
Connectto
ExposedMetal
Parts
MeasuringCircuit
Resistance=2000 ohms
Fig.1-1 AC Leakage Current Test Circuit
mA

2
1.2 Product Safety Notice
1) Many electrical and mechanical parts in this chassis provide special visual safety protection.
The protection afforded by them cannot necessarily be obtained by using replacement
components rated for higher voltage, wattage, etc.
2) 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.
1.3 Service Notes
1) When replacing parts or circuit boards, wrap the wires around terminals before soldering.
2) When replacing a high wattage resistor (more than 1/2 W) on a circuit board, keep the resistor
about 10mm (1/2in.) 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.

3
2. Specifications
2.1 Monitor Specification
Power Source AC 100 ~240V , 50 / 60Hz
LED color is green Normal Operation (Max.70W)
LED color is amber Stand By / Suspend Mode (Max.15W)
Power
Consumption LED color is amber Off Mode (Max. 3W)
Picture Tube 15" (Diagonal), glare, non- glare, anti-static, 90°Deflection,
0.28mm dot pitch, Low Radiation, Mini-Gun Tube.
Viewable Image
Size 13.9" (Diagonal)
Horizontal 1024 Pixels (Non-Interlaced)
Maximum
Resolution Vertical 768 Lines (Non- Interlaced)
Input Signals Video Analog 0.7 Vp-p / 75 ohm Positive
Separate Sync.
TTL Level
Horizontal : Positive / Negative
Vertical : Positive / Negative
Synchronization Horizontal 30KHz - 57KHz continuous
Vertical 50Hz - 120Hz continuous
Display Colours Analog Input 16 million colours
Horizontal 260 mm
Active Display
Area Vertical 195 mm
Plug & Play DDC1 / 2B
Operating
Temperature +5• ~ +35•
Operating
Humidity 10 % ~ 80 % (Non-Condensing)
Storage
Temperature -20• ~ +65•
Storage
Humidity 15 % ~80 %
High Voltage 25KV
Dimension Width 360 mm
Height 384 mm (With Base)
Height of Base : 58mm
Depth 388 mm
Weight 11.3Kg (Net weight)/ 13.5Kg (Gross weight)

4
2.2 Preset Timing Table(I) for HP
Mode Resolution H-Freq. V-Freq. Hs. pol. Vs. pol.
1 720 x 400 31.47 kHz 70.08 Hz Negative (-) Positive (+)
2 640 x 480 31.47 kHz 59.95 Hz Negative (-) Negative (-)
3 640 x 480 35.16 kHz 56.25 Hz Negative (+/-) Negative (+/-)
4 800 x 600 37.88 kHz 60.32 Hz Negative (+/-) Negative (+/-)
5 640 x 480 37.86 kHz 72.81 Hz Negative (+/-) Negative (+/-)
6 640 x 480 37.50 kHz 75.00 Hz Positive (-) Positive (-)
7 800 x 600 48.08 kHz 72.18 Hz Positive (+/-) Positive (+/-)
8 1024 x 768 48.36 kHz 60.00 Hz Negative (-) Negative (-)
9 800 x 600 53.67 kHz 85.00 Hz Positive (+) Positive (+)
Preset Timing Table(II) for others
Mode Resolution H-Freq. V-Freq. Hs. pol. Vs. pol.
1 720 x 400 31.47 kHz 70.08 Hz Negative (-) Positive (+)
2 640 x 480 31.47 kHz 59.95 Hz Negative (-) Negative (-)
3 640 x 480 37.50 kHz 75.00 Hz Negative (-) Negative (-)
4 640 x 480 43.30 kHz 85.00 Hz Negative (-) Negative (-)
5 800 x 600 46.88 kHz 75.00 Hz Positive (+) Positive (+)
6 800 x 600 53.67 kHz 85.00 Hz Positive (+) Positive (+)
7 1024 x 768 48.36 kHz 60.00 Hz Negative (-) Negative (-)
8 1024 x 768 56.47 kHz 70.00 Hz Negative (-) Negative (-)

5
3. Control Location and Functions
3.1 Indication LEDs :
When one of the digital controls is selected, the corresponding LED(s) are lit.
CONTRAST : To adjust the contrast of the display.
BRIGHTNESS : To adjust the brightness of the display.
H-POSITION : Adjust the horizontal position of the entire screen image.
H-WIDTH : Adjust the horizontal width of the entire screen image.
V-POSITION : Adjust the vertical position of the entire screen image.
V-HEIGHT : Adjust the vertical height of the entire screen image.
PINCUSHION : If the vertical sides of the screen image curve in or bulge out,
you can correct the pincushion distortion using this adjustment.
TRAPEZOID : If the picture is wider at the top or bottom, you can correct the
trapezoid distortion by using this adjustment.
PARALLEL : If the sides of the screen image are tilted, you can use this
adjustment to correct the parallel distortion.
ZOOM : This is used to adjust H-width and V-Height, simultaneously.
RECALL : This is used to recall the original factory display settings.
Front View Rear View
1. Indication LEDs 1. AC Power Plug
2. Control Buttons 2. Signal Cable
3. Power Switch's LED
4. Power Switch
1. 2. 3. 4. 1. 2.

6
3.2 Control Buttons :
The Select Button (the left button) selects a digital control. The selected control is indicated by
the corresponding indication LED. The Down (down arrow) and UP (up arrow) buttons allow you to
decrease or increase the value of the selected control.
Press the Down (down arrow) and up (up arrow) simultaneously, Then it will degauss the
display.
3.3 Power Switch and LED
Push to power on the monitor and push again to power off. The indicator LED will be green
when the power switch is ON and the power cord is properly connected. The color of the LED
depends on the power state of the monitor. When the LED color is permanently green, it
indicates the monitor is at normal state. And when the power LED is amber, it indicates the monitor
is at a power saving state.
We recommend you switch on the monitor first, before switching on the computer!

7
4. Disassembly Instructions
1) Face Down the Monitor : ( Fig.4-1 )
2) Swivel Base Removal : First press the stopper, then slide the swivel ball down and remove it.
( Fig.4-2 )
3) Back Cover Removal : Remove 4 screws (A) ( Fig.4-3 ) and (B) (Fig. 4-4) from the back cover.
Then remove the back cover.
4) PCB Assembly Removal :
CAUTION: When serving or replacing the CRT, disconnect the anode and discharge the anode
completely. As high voltage (25.0KV) may remain on the anode for an extended time after
power off.
( Fig.4-1 ) ( Fig.4-2 )
(A) (B)
( Fig.4-3 ) ( Fig.4-4 )
Stopper

8
a) Unplug grounding connectors and the degaussing coil grounding connector from the CRT
drive shield.
b) Remove CRT drive board (C) from CRT neck. (Fig.4-5)
c) Unplug the DY connector, AC connector, Degaussing coil connector and the CRT
grounding connector from the FBT shield.
d) Discharge the remaining static electricity by shorting CRT anode and ground, then remove
the FBT anode connector.
f) Press two clips(D) from left and right side of front cover(Fig.4-5) to remove main chassis.
5) CRT Removal :
CAUTION : Do not lift the CRT by the neck.
a) CRT is supplied as ITC.
b) Remove 4 screws (E) from the front cover (Fig.4-6) to move the CRT.
(C)
(D) (E) (E)
( Fig.4-5 ) ( Fig.4-6 )