Tatung C7BTR Schematic
T
atung
SERIES
C7BTR
Low Radiation Extended VGA
PLUG & PLAY COLOUR MONITOR
SERVICE MANUAL
TABLE OF CONTENTS
PAGE
1. Precautions and notices……………………………………1
2. Specification……………… ………………………………3
3. Control Location and Functions …………………………. 5
4. Disassembly instructions ………………………………… 7
5.General Connections & applications…. …………………. 10
6.Electronic Circuit Description …………………….………12
7.Adjustment ……………………………………..…………24
8.Troubleshooting follow Chart …..………………….……. 30
9.Black Diagram …………………..………………………. 36
10.PCB Layout …………………………………………… 37
11.Circuit Diagram ……………………………………..……39
12.Mechanical Disassembly …………………………………40
13.Mechanical Parts List ………………….…………………40
14.Electrical Parts List ……………….………………………41
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 of 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 so equipped should be kept away while handing picture tube.
Keep picture tube away from the body while handing.
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 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. Proceed as follows.
MAINS INPUT
MEASURENG
CONNECT TO
EXPOSED METAL PARTS
Connect the monitor power lead to the mains supply, via an isolation transformer, and switch on,
Using the test circuit shown in Fig1-1 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 3.5mA
1-2 product safety notice
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..
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 1/2w) on a circuit board keep the resistor
about 10mm (1/2 inch) 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.
5. General Connection & Applications
Procedure for installing and using this model of ultra Super-VGA color display .
1. Set up the display at the desired operation location , on top of or beside your personal
computer . Plug the power cord into the monitor and then connect the other end of the
power cord into an AC outlet . The three-wire power cord is shielded type and is
provided as a Safety Precautions to ensure proper electrical grounding .
2. Connect the 15-pin color display shield signal cable to the video adapter output on your
computer , then lock both screws to ensure proper grounding . The connector information
is as follows :
PIN Description
1 Red
2 Green
3 Blue
4 Ground
5 Ground
6 Red Ground
7 Green Ground
8 Blue Ground
9 No Connect
10 Ground
11 Monitor sense 1
12 SDA
13 Horizontal Sync.
14 Vertical. Sync.
15 SCL
3. First turn the PC power switch ON . Then apply power to the display by pressing the power on/off switch to power
1
6
11
5
15
the monitor on . The power indicator light will illuminate . Waiting about thirty seconds for the display tube to warm up , data
will be displayed on screen .
4. Adjust the BRIGHTNESS and CONTRAST controls for the best readability . Adjust the
H-Width and H-Position control as necessary for proper horizontal display .
5. V-Height can be adjusted to give you a proportional vertical display .
6. Connect the audio and microphone to PC .It could generate the sound from CD player .
If PC connected to the network of modem , then it could use the microphone to interview with the other people .
NOTE :1. If your extended VGA color display requires service . Refer to the control and adjustment information in this
publication and verify that all controls and adjustment of the display are properly set .
2. If your display does require service it must be returned with the power cord .
2. Specifications
Display CRT Size 17”
CRT Dot Pitch 0.27mm
Max. Resolution Mode 1280×1024 @ 60Hz Non-Interlaced
Display Area 12.05”×9.05” (306mm ×230mm)
Signal Video Signal Level Analog 0.7 Vp-p / 75 ohm
Synchronization H/V Separate( TTL ) positive
Signal Connector 15-pin mini D-sub
Frequency Horizontal Scan 30KHz ~ 70KHz (continuous)
Vertical Scan 50 ~ 120Hz (continuous)
Video Bandwidth 100MHz
User Control Front
Control Keys => • (Down) and •(Up)
Power ON/OFF ,Power LED
Power Power Input AC 100-120 /200-240 V, 50/60Hz , 1.4A
Power Consumption
View-able Diagonal Area 15.9”
Select Keys =>< (Left) and > (Right)
100 Watts Max
Environment Operating Temperature 5 to 35 degree C
Condition Operating Humidity 10 to 80 percent (non-condensing )
Storage Temperature -40 ~ + 65 degree
Storage Humidity 5 ~ 95 percent
Dimension ( W ×H ×D ) (with base) 416 ×447 ×427 mm
Net Weight 16.9 Kg
3
Time Table For Sync. Signal
Mode No. 1 2 3 4 5 Unit
Resolution 640×480 720×400 640×480 800×600 640×480
Horizontal Frequency 31.468 31.468 37.500 37.878 43.269 KHz
(A)Horizontal 31.778 31.778 26.667 26.4 23.1 usec
(B ) Horizontal Pulse Width 3.813 3.813 2.032 3.2 1.556 usec
(C ) Horizontal Back Porch 1.907 1.907 3.810 2.2 2.222 usec
(D) Horizontal Active Area 25.422 25.422 20.318 20.0 17.778 usec
(E ) Horizontal Front Porch 0.636 0.636 0.18 1.0 1.556 usec
(F ) H. Sync. Polarity - - - + -
Vertical Frequency 59.943 70.000 75.000 60.31 85.0 Hz
(O) Vertical Period 16.683 14.268 13.333 16.579 11.764 msec
(P ) Vertical Pulse Width 0.064 0.064 0.08 0.1056 0.069 msec
(Q) Vertical Back Porch 1.049 1.112 0.427 0.607 0.578 msec
(R ) Vertical Active Area 15.253 12.711 12.800 15.84 11.093 msec
(S ) Vertical Front Porch 0.318 0.381 0.027 0.0264 0.023 msec
(T ) V. Sync. Polarity - + - + -
Interlaced No No No No No
Mode No. 6 7 8 9 10 Unit
Resolution 800×600 1024×768 800×600 1024×768 1024×768
Horizontal Frequency 46.875 48.363 53.674 68.667 56.476 KHz
(A)Horizontal 21.333 20.677 18.631 14.561 17.707 usec
(B ) Horizontal Pulse Width 1.616 2.092 1.138 1.013 1.813 usec
(C ) Horizontal Back Porch 3.232 2.462 2.702 2.2 1.92 usec
(D) Horizontal Active Area 16.162 15.754 14.222 10.836 13.653 usec
(E ) Horizontal Front Porch 0.323 0.369 0.702 0.471 0.521 usec
(F ) H. Sync. Polarity + - + + -
Vertical Frequency 75.000 60.004 85.061 85 70.069 Hz
(O) Vertical Period 13.333 16.666 11.756 11.764 14.272 msec
(P ) Vertical Pulse Width 0.064 0.124 0.056 0.044 0.106 msec
(Q ) Vertical Back Porch 0.448 0.600 0.503 0.524 0.513 msec
(R )Vertical Active Area 12.800 15.88 11.179 11.182 13.599 msec
(S ) Vertical Front Porch 0.021 0.062 0.019 0.014 0.054 msec
(T ) V. Sync. Polarity + - + + -
Interlaced No No No No No
6. ELECTRONIC CIRCUIT DESCRIPTION
6-1. Switching Mode Power Supply (SMPS)
The switching mode power supply for this monitor is a full range type.
Universal power input of AC 100V ~ 240V is compatible.
The AC input is supplied through the slow blow fuse F801, the first line T802,
the signal pole power switch S801 to the rectifier D811 ~D814.The rectified DC voltage
is about 125V ~ 335V and is fed to the switching transformer T801 via R808.
Prior to starting, a small current flows to C866A via R849, Q850, and R850. I862 can operate
immediately when the voltage across C866A reaches 16V. At the same time, Q868 is on; the
rectified current flows through the primary winding of T801 and the energy is stored in it.
The energy is transferred to the secondary winding when Q868 is off, the auxiliary winding is
well close -coupled and keeps in phase with the secondary winding,
It will provide the stable voltage on C866A and feed it to pin 7 of I862 via R831, D831, and D870.
The I862 will keep working if the voltage across C866A is over 10V.
The oscillating frequency of the switching mode power supply is around 30KHz, which is
determined by the timing components R861/C863.
Capacitor C863 is charged to 2.8V via the 5V-reference voltage on pin8 of I862 and discharge
to 1.2V through R861. During the discharge time interval, the oscillator generates a series of
square waves, which cause the output at pin6 of I862 to go low state.
The fly-back pulse from T440 is buffered by R864 and differentiated by C864, R863. A sharp
pulse is thus obtained to force C863 to discharge so that the oscillating frequency can be
synchronized and keeps in phase with horizontal frequency in order to avoid unwanted interference
on the display screen.
The voltage varies due to the charge of input AC or output loading change, the auxiliary
winding will reflect this variation on pin2 of I862 via R831, D831, R835.The voltage at pin2 of
I862 will be compared with the internal 2.5V-reference voltage to produce an error voltage which
is limited to 1V by internal zenor diode and be compared with the voltage at pin3 of I862 which is
supplied from the voltage detected across R867. When Q868 is on. Only Q868 is off when the
voltage-drop across R867 has reached that of the error voltage or1 V p-p maximum.
The error voltage controlled the duty cycle of the pulse width modulator to regulate the output
voltage. If over-load or short circuit occurs at the secondary, the voltage across R867 reaches over
1 V p-p rapidly, thereby blocking the power output, the voltage at pin7 of I862 then decrease to
below10V and I862 is forced off.
However, in order to allow auto-recovery from power saving off state, the SMPS circuit is
designed as an unlatched type, the DC current flows via R849 Q850, R850 to charge C866A again,
when the voltage across C866A has reached 16V, I862 is turned on again. Once the peak voltage
across R867 is over 1Vp-p, I862 will be forced off again.
Consequently, the I862 is turned on and off repeatedly, and the power is not be switched off,
Q868 and R808 may be over stressed and fail.
6-2 Power Management Circuit
There are four modes of indicator in this power LED described as below, the first mode,
“green-indicator “ indicates the normal state; “yellow-indicator“ indicates the stand-by state mode
The fourth mode, “ amber-indicator “ indicates the power saving off state. Both H. sync and V.
sync are off
I501
MODE
NORMAL 1 1 1 1 GREEN
STAND BY 1 0 0 1 YELLOW
SUSPEND 0 1 0 1 YELLOW
#40
V
#39
H
#23 #21 D862
LED
OFF 0 0 0 0 AMBER
When the display signal enters the “suspend “ state of power saving, with V. sync off, the
voltage at pin31 of I501 is low, Q821 is OFF, and Q820 is OFF too. This will shut down the
oscillation of the horizontal and vertical deflection, then power conservation is achieved.
When the display signal enters the “ off ” state of power saving with both H. sync and V. sync
off, the voltage at pin31& pin 29 of I501 are low, then Q820 and Q822 are off, there is no 8V &
14V Voltage for the circuit.
The overall power dissipation is significantly reduced to less than 5W watt; exclusive audio
power consumption.
To recovery from off state to normal state is automatic since the recovery H. sync and V. sync
will trigger I501 via Q550 &Q556, The voltage on pin 29 & 31 will go to high again and turn on
Q822, Q820 via Q823, Q821
.
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