Tatung TUK-VM77S Schematic

Service Manual

17-inch Color Monitor VM77S

Service Manual Versions and Revision

No. Version Release Date Revision

1. 1.0 May 17, 2002 Original release

VM77S

copied, reproduced, translated, or converted to any electronic or machine readable form without prior written permission of Tatung (UK) Ltd.

VM77S Service Manual. Printed in Taiwan.

VM77S

1500 ohm 10 watt

To exposed metal

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

To known

earth ground

0.15ufd

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 will constitute a potential shock hazard and must be corrected immediately.

VM77S

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 there are any unforeseen conflictions 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 on and making sure the monitor is working properly, the HiPot & 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.

d) Plug monitor power cord to the Hi Pot tester terminals.

Test Equipment

e) Turn on tester and watch the indicator or beeper. f) If the indicator lamp lights, 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.

VM77S

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.

Monitor

2 Product Specifications

2-1 Specifications

17-inch (16-inch Visual image area), sloted mask, 90 degrees

Picture Tube

deflection, dot type black matrix, medium short persistence

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

0.28 mm dot pitch

VM77S

Scanning Frequency

Maximum Resolution 1280 dots (H) x 1024 lines (V) @60Hz refresh rate

Display Area 306 mm (H) x 230 mm (V) typical

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

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 75 Watts (maximum) AC rated voltage, 100VAC to 240VAC

Misconvergence Center Area : < 0.3 mm; Corner Area : < 0.4mm

User Controls Power On/Off, Contrast, Brightness, Horizontal Size, Horizontal

VGA, Super VGA, 1024x768@60/70/75/85 Hz

1280x1024@60Hz

Unlimited Colors

Horizontal : 30 to 70 kHz Vertical : 50 to 160 Hz

Position, Vertical Size, Vertical Position, Pincushion, Trapezoid, Rotation, Color temperature, Language, Display Frequency, Degauss, Recall, H. Moire, V. Moire

Service Controls PWB-1552

PWB-1563 : power voltage adjust (VR801), high voltage adjust

Preset Modes 8 (see Table 2-2. Timing Chart)

Environmental

Considerations

Operation temperature : 10oC to 40oC ambient Operation Humidity : 20% to 80% ambient Storage temperature : -40oC to 65oC ambient Storage Humidity : 10% to 90% (non-condensing)

Altitude : Non operating 40,000 feet sea level operating 10,000 feet sea level

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

2-2 Signal Cable Pin Connections

Table 2-1. Signal Cable Pin Assignment

Pin Signal Pin Signal

1 Red video 9** +5V

2 Green video 10 Digital Ground 3 Blue video 11 Ground 4 Ground 12 SDA 5* NC 13 H-Sync 6 Red ground 14 V-Sync/VCL 7 Green ground 15 SCL

VM77S

8 Blue ground

Note * This pin is used for selftest detection. Connect this pin to ground at the PC end. ** For PC 99: This pin will provide +5V from PC side.

VM77S

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 1 2 3 4 5 6 7 8

H. Dots 640 640 640 800 800 1024 1280 1024

V. Dots 480 480 480 600 600 768 1024 768

H-freq (kHz) 31.47 37.5 43.3 46.8 53.67 60.02 63.98 68.68

Sync Polarity - - - + + + + +

A period us 31.78 26.666 23.111 21.333 18.63 16.66 15.63 14.56

B Blanking us 6.356 6.35 5.33 5.172 4.409 3.657 3.778 3.725

C Sync us 3.81 2.03 1.556 1.616 1.138 1.219 1.037 1.016

D B.P. us 1.907 3.81 2.222 3.232 2.702 2.235 2.296 2.201

E Active us 25.42 20.32 17.778 16.162 14.22 13 11.852 10.836

F F.P. us 0.636 0.51 1.556 0.323 0.569 0.203 0.444 0.508

V-freq (Hz) 59.95 75 85 75 85 75.03 60 85

Sync Polarity - - - + + + + +

O Period ms 16.68 13.33 11.764 13.333 11.76 13.33 16.661 11.77

P Blanking ms 1.43 0.533 0.67 0.533 0.578 0.533 0.656 0.582

Q Sync ms 0.064 0.08 0.069 0.064 0.056 0.05 0.047 0.044

R B.P. us 1.02 0.427 0.578 0.448 0.503 0.466 0.594 0.524

S Active us 15.25 12.8 11.093 12.8 11.18 12.8 16.005 11.18

T F.P. us 0.35 0.026 0.023 0.021 0.019 0.017 0.016 0.015

Seperate Sync

Horizontal

Video

Vertical

Video

Sync

H.Parameters:

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

Sync

V.Parameters:

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

VM77S

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 Normal* Green

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.

* For power consumption : 75W Max. (@ 230V AC, preset size and maximum light output condition)

<5 watts Amber

LED

Light

VM77S

3 Operation Theory

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

3-1 Main Features

1. Simplified design with minimum components.

2. The MYSON MTV212 M(A) 32 processor-- that has I2C BUS controlled geometric correction, contrast and brightness-- offers the functions for: (a) Contrast, (b) Brightness, (c) H-size, (d) H-position, (e) Vsize, (f) V-position, (g) Pincushion, and (h) Trapezoid.

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

- Suspend & Stand-By, (d) Power saving override, (e) DDC1/2B, (f) I2C Bus for auto-alignment through signal cable (g) CS1/CS2/CS3/CS4 for linearity and size compensation.

3. Stores up to 10 factory preset modes and offers 8 user modes. There are 16 function icons at OSD. They are controlled by 1 2 keys on front panel.

4. Powerful PHILIPS TDA4863 and TDA4841 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 > = 70 kHz.

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

3-2 Microcontrol Section

1. This monitor uses MYSON MTV212 M(A) 32 CPU. It contains a 8051 8-bit CPU core, 256 bytes of RAM used as working RAM and stack area, 32k bytes of OTP ROM, 13-channel 8 bit PWM D/A converter, 2-channel 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 allowed 8 factory preset modes and 8 user modes. There are 11 functions, Contrast, Brightness, H. Size, H. Position, V. Size, V. Position, Pincushion, and Trapezoid, Rotation, H. Moire, V Moire, all controlled by OSD icon which can be adjusted by user.

3. The pin 27 and pin 28 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 1 & 2 keys, they are detected by sensing the voltage through R710, R740, R741, R743, R716, R717 to pin 25 and 26 of I701.

3-3 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 I2C bus. SDA and SCL signals coming from microprocessor feed to pin 19 and pin 18 to control all functions.

+ 22 hidden pages