Tatung TUK-VM77S Schematic

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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

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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.

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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.

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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.

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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

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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

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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.

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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

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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

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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.

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3-3-1 Horizontal Section

1. The osci llator is driven by the currents in R419 and R420. The minimum oscillator frequency is determined by R419 and the maxi mum frequency is determined by R420.

2. Hori zontal sync goes into pin 15 through R318. And horizontal flyback pulse goes into pin 1 through R401 and bypass fil ter C403 from pin 6 of FBT and R496 for HFLB loop.

3. Horizontal driver (pin8) O/P t o Q401 via C410.

3-3-2 Vertical Section

1. Verti cal sync goes into pin 14 through R317.

2. The free running frequency is determined by R301 and C301.

3-3-3 Vertical O/P section

1. The di fferential output currents from pin 13 of Vout1 and pin 12 of Vout2 can be directly coupled to the vertical deflect ion booster pin 1 and pin 2 of TDA4863.

2. The TDA4863 has two output stages which are current driven in opposite phase and operat e in combination wi th the deflection coil in a full bridge configuration.

3. This IC is powered by two sets of posit ive voltage and one set of negative voltage. (+12V at pin 1, -12V at pin 4, +40V at pin 2).

3-3-4 E-W/Trapezoid and H. Width Controls

1. The horizont al O/P stage uses diode modulator D419, D433, C411, C412, L409 and C418 for East-West (P incushion) Trapezoid and H. width controls.

2. The scan current i s determined by B+ mi nus Vm ( the voltage of C418) values and the pincushion control is accomplished by Darli ngton pair Q418 and Q419 by coupling a parabola waveform from pin 11 of TDA4841. The H. width / corner and trapezoid correct ion are also accomplished by this pin 11. The DC level control s H. size. The AC level is combined with side pin and trapezoid corners functions.

3-3-5 X-Ray Protection

1. T o avoid X-ray hazard, a DC voltage generated at pin 6 of FBT and rectified by D408, C432 and divided by R403, R404 and R405 come int o pin 2 of TDA4841.

2. If t his voltage is higher than 6.39 V, then TDA4841 will be activated to float HUNLOCK (pin17), H. DRV( pin 8), B DRV (pin 6), VOUT1 (pin 12), VOUT2 (pi n13). After that all deflection circuit stop worki ng.

3-3-6 G1, Blanking and Brightness

1. The vert ical blanking signal comes from two ways. One is from pin 8 of I301 (TDA4863), the other is from verti cal sync (pin 32 of I701). These two positive vertical pulses through Q405 amplified and converted into negative pulse and sent to G1 for vertical blanking.

2. In protect ion mode or an out-of- range situation HUNLock will send 5 V pulse to cutoff Q407, then G1 wil l go down to -150V. During the mode change, Mute acts as same as HUNLock’s.

3-3-7 Contrast Section

1. Contrast i s controlled by I701 through I2C bus to I501 (LM1267) directl y.

2. Beam current is detected through T402 (FBT) pin 7, C429, R449 and detected voltage feeding into Q432,

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Q433, R436, R497, R459, C482 to control I501 pin 22 voltage. When I501 pin 22 voltage drops below 4.1 V, the ABL function will happen.

3-3-8 H/V size breathing compensation

1. Beam current is sensed as above section (3-3-7 item 2) and this voltage routes through R451, R468, C470 then through R437 to I401 pin 31 for H. size compensation.

2. HV voltage is detected through T402(FBT) pin 11. C481, R4F4, R4F8, R4F9, Q428, R4G0, Q431, R4G1, then through R302 to I401 pin 21 for V. size compensation.

3-3-9 Dynamic focus circuitry

The dynamic focus is applied to improve the corner focus performance, it includes horizontal and vertical dynamic focus.

1. Horizontal dynamic comes from C413 through R435, C450, T401, R434, C448 and feed to FBT dynamic focus pin (T401 pin 12).

2. Vertical dynamic comes from I401 pin 32 through C315, R322, R326, R321, R323, Q301, R324, R325 and feed to FBT dynamic focus pin.

3-4 Power Supply Section

3-4-1 AC Rectifier

The circuit can accept 90 V to 264 V AC input through D801~D803 bridge diodes and C808 filtering to get DC 126 V~364 V for power conversion in T802.

3-4-2 Line Filter

It consists of C803, T801, C804, C805, C808, C819, C807, C817 and meets EMI regulation.

3-4-3 Power LED Status

1. The LED has 3 leads with common cathode to emit green and amber color light for different power saving states. It is controlled by CPU.

2. Normal : Green light Amber LED is off because CPU pin 30 is 1.96V and pin 31 is 0.45V, only green LED is turned on.

3. Off Mode : Amber light CPU pin 30 is 1.87V and pin 31 is 0.46V, then green is off and amber is illuminated.

3-4-4 Auto Degaussing

When S801 turns on, pin 14 of I701 will send a signal to Q802 and turns on RL801 for degaussing. After 4 seconds, it will turn off RL801 automatically.

3-4-5 PWM Control

1. Start Up The I801 (5S0765C) gets power from R807, R808, C830 and pin 3 voltage reaches 15 V for starting up.

The I801 starts oscillation at 20 kHz, pin 1 output to drive T802. Switching on, R819 set up an 15 V to keep I801 working through D809 auxiliary voltage.

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2. Regulation The DC O/P voltage is proportional to the auxiliary voltage, so I801 pin 4 senses the feedback voltage

from the divider D806, R809, C810, VR801, Q803, Q801 and R821 to compare with the built-in 1.5 volts reference voltage for error amplifier operation. Finally pin 6 can modulate the different duty cycle by VR801 setting to achieve regulation purpose.

3-4-6 Synchronization

1. Normal Mode The sync pulse from FBT (31 kHz~69 kHz) via R812, R811 and C815 to pin 5 of I801 to keep I801

synchronized with horizontal sync input frequency.

2. Power Saving Modes: Standby/Suspend Because there is no pulse from FBT, so the free-run frequency SMPS works at 20 kHz by I801 itself.

3. Override The horizontal free run frequency is about 63.2 kHz under override condition, SMPS is synchronized to

this frequency.

3-4-7 O.V.P.

If the auxiliary voltage is higher than 25 volts makes pin 3 of I801 is limited to have the OVP activated.

3-4-8 O.P.P.

The excess current of T802 through I801 pin 1, 2, make Vs>1.1V internal of I801, then limite the power.

3-4-9 Step Up Power Supply For FBT

1. The B+ of FBT is proportional to horizontal frequency, that is the higher frequency, the higher voltage. The basic voltage is 58 volts from T802 pin 10 via L811, D813, C824 and the gate control of Q451 comes from I401 pin 6 via Q450, Q434, D435 and R4E5. The duty cycle is controlled by I701 pin 33 (PWM pin Adj.) via R719, C741, R4F6, R4F5, R4F1.

2. The regulation and boost up (from 68 V to 160 V or more, on demand). The H.V. is set at 25.6 kV (zero beam) by I301 pin 33 which senses the secondary O/P from FBT. The booster comprises Q451, L410, L411, D450, C425 and T802 to offer the required B+ for different frequency modes.

3-5 Video Amplifier Section

1. RGB signal inputs are terminated by R501, R531 and R561 then pass through the coupling capacitors C503, C533 and C563 to IC501 LM1267 preamplifier.

2. The amplifier RGB signals (0~3 Vpp) are adjusted by I2C bus, I501 pin 23 is for clamp pulse which comes from pin 16 of TDA4841 to set up equal clamp level.

3. The video output stages are amplified by I502 (LM2469).

4. The RGB cathodes cut off are adjusted by I503 (LM2479) pin 8, 7, 6, which comes from I501 pin 16, 15, 14 to adjust cut iff voltage level by I2C bus.

5. Under override condition, “NO SIGNAL” will show up on the screen.

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3-6 OSD (On Screen Display) Circuit

1. The I504 MTV021-21 is OSD IC. The OSD signals are worked by positive vertical pulse from I701 pin 34 that goes through R720 to I502 pin 10, and positive horizontal pulse from T402 pin 5 goes through R496 to I502 pin 5. CPU I701 pin 13, 12 (I2C bus) transfers information to I502 pin 7, 8.

2. The OSD R. G. B signals and blanking signal are terminated at I502 pin 15, 14, 13, and 12 to I501 pin 1,2, 3 and 4 then the OSD picture appears.

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4 Alignments and Adjustments

This section of the service manual explains how to make permanent adjustments to the monitor settings.

4-1 General Adjustments

4-1-1 Adjustment Conditions

a) Power Supply

Apply AC 115 V or 220 V

b) Warm-up Time

The monitor must be powered on for 15 minutes before starting any alignment, but requires 30 minutes of warm-up time for convergence adjustment.

c) Signal Input

1. Video: RGB Analog, 0.7 Vp-p, positive

2. Synchronization: Horizontal and vertical TTL signal, separate, positive or negative

3. All adjustments should be made using a signal of FH = 68.68 kHz, FV = 85 Hz, unless otherwise defined.

4-1-2 Equipment Required

The following equipments are necessary for adjustment procedures:

1. Volt-ohm-A meter (Sanwa FD-750C or equivalent)

2. 30 kV high voltage probe (HP34111A)

3. Oscilloscope (TEK2235 or equivalent)

4. Minolta Color Analyzer II

5. Signal generator (IBM PC with proper display cards or Chroma 2000)

6. Screwdriver

4-1-3 Switching Power Supply and Regulator Adjustment

a. The regulated B+ control has been preset in the factory and needs no adjustment. However, if any repair

is made on the power supply section, the following readjustment procedures are recommended:

1. Allow the monitor to warm-up for about 15 minutes.

2. Apply VGA (1024 x 768 @ 68.68 kHz/85 Hz) signal to the monitor.

3. Connect a DC voltage meter to TP001 (on the Main board), and adjust VR801 for 11.7 ± 0.1 Vdc

4. If a fuse is broken during adjustment, remember to replace it with the exact same type of fuse.

b. If necessary, follow the following procedures to enter the factory mode.

1. Press both 1 key and 2 key simultaneously then power ON.

2. After turn the power off, this monitor will go back to normal mode.

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4-2 Alignment Procedures

4-2-1 High Voltage Adjustment

CONDITION

Press 1 and 2 buttons simultaneously when switching the power “On”. Di splay image : No video (68.68kHz Mode)

PROCEDURE

Connect DC meter t o TP002 and adjust HV (icon) Obtain a DC voltage of -152.2 ± 0.2 V DC (Sampo FBT) or -153 ± 0.2V DC (LCE FBT) for CPT CRT

M41AGE93X46 (TCO) or M41AGE 83X46 (MPRII) .

4-2-2 Screen and White Balance Adjustment

CONDITION

Press 1 and 2 buttons simultaneously when switching the power “On”. Di splay image : No video (68.68kHZ Mode)

PROCEDURE

1 Rast er color setting 1-a. Set Bright ness max. to 77 (OSD cursor) and 563 ± 5 at G2. 1-b Adj ust R and B cutoff to min. 1-c Adj ust G cutoff to about 0.45FL 1-d Adj ust B cutoff to get y=280 ± 5, R cutoff to get x=280 ± 5 and Y=0.65 ± 0.05 FL. 1-e Adj ust Brightness cutoff to raster 0.01-0.02 FL.

CONDITION

Di splay image : 50 mm x 50 mm white block pattern

PROCEDURE

2 65000K col or temperature setting 2-a. Set Brightness to cutoff and Contrast to maximum. 2-b Move cursor on OSD t o choose color temperature icon. 2-c. W ith green block pattern, adjust G gain to get Y about 32FL. 2-d Adj ust R.B. gain to get x=313 ± 5, y=329 ± 5; and Y=43 ± 0.5FL

3 93000K col or temperature setting 3-a. Set Brightness to cutoff and Contrast to maximum. 3-b Move cursor on OSD t o choose color temperature icon. 3-c. W ith green block pattern, adjust G gain to get Y about 32FL. 3-d Adjust R.B. gain to get x=283±5, y=297±5; and Y=43±0.5FL

4 Full white ABL setting

CONDITION

Display image : full white pattern 4-a Set Brightness to cutoff and Contrast to maximum. 4-b. Adjust ABL to Y=29.5FL ± 0.5FL. 4-c. Check the white balance at 5FL and 28FL. 4-d. Repeat all the procedures in 4-2-2 section until the best white balance is obtained.

4-2-3 Focus Adjustment

CONDITION

Display image : “me” character pattern (68.68 kHz Mode)

PROCEDURE

1. Set Brightness to cutoff and Contrast to maximum.

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2. Adjust focus 1 at T402 (static focus VR) to make vertical line clear.

3. Adjust focus 2 at T402 (static focus VR) to make horizontal line clear.

4. Repeat above procedures to get best focus.

4-2-4 Static Convergence Adjustments

Static convergence involves alignment of the red, blue and green lines in the center area of the display. Note : The monitor requires 30 minutes of warm-up time for convergence adjustment.

CONDITION

Display image : Crosshatch pattern Warm-up Time : 30 minutes

PROCEDURE

1. Set Brightness and Contrast to display a well-defined pattern.

2. Ensure the convergence magnet rings are correctly positioned on the CRT.

Figure 4-1. Convergence Magnets on the CRT

8 76 5 4 3 2

1) Setup Bolt 2) Bow Magnet 3) Band 4) 2-Pole Magnet

5) Spacer 7) Spacer

9) Holder

6) 4-Pole Magnet

11) Tabs10) Band

CRT

FRONT

8) 6-Pole Magnet

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Red/

movement

3. Rotate the individual rings of 4-pole convergence magnets by changing the spacing between the 2 tabs to converge the vertical red and blue lines at the center of the screen.

4. Rotate the pair of rings of 4-pole convergence magnets by maintaining spacing between the 2 tabs to converge the horizontal red and blue lines at the center of the screen.

5. Rotate the individual rings of 6-pole convergence magnets by changing the spacing between the 2 tabs to converge the vertical red, blue and green lines.

6. Rotate the pair of rings of 6-pole convergence magnets by maintaining spacing between the 2 tabs to converge the horizontal red, blue and green lines.

7. Repeat the steps from 3~6 until the best convergence is obtained.

Figure 4-2. 4-pole and 6-pole Magnets Movement

Blue Green

6-pole magnets

Blue Red

Red/ Blue

Green

4-pole magnets

Note : The 4-pole magnets and the 6-pole magnets interact, making dot movement complex.

4-2-5 Degaussing

Degaussing is required when poor color impurity appears on the screen. This monitor uses an automatic degaussing circuit that is activated when the power is on. The automatic degaussing will be fully functional again after the monitor has been in operation for 20 minutes.

The degaussing effect is confined to the picture tube since the coils are mounted at the back of the tube. Should any part of the chassis or cabinet becomes magnetized, it is necessary to degauss the affected area with a manual degaussing coil.

4-2-6 Manual Degaussing

1. Apply line voltage to the degaussing coil and move it in a rotary motion over the front, sides, and top of the monitor. The coil should be kept away from the rear of the monitor to avoid damaging the magnetic neck components.

2. Slowly rotate and move the coil away from the monitor to about 6 feet beyond the point where no effect on the CRT will be noticeable.

For proper degaussing, it is essential that the field be gradually reduced by moving the coil slowly away from the monitor. The degaussing coil must never be shut off or disconnected while near the monitor, as this would introduce a strong field instead of canceling the effect of the stray fields.

5 Troubleshooting

I703, R719, C741,

5-1 No Raster

VM77S

No Raster

Measure

voltage of B+ at

T402 pin 2 on

PWB-MAIN

Yes

Check DC

B+ line, Q451,

Q402, T402

0 V

Short Circuit

at load?

Check voltage

of C808

Yes

Check

I801, R807,

R808, Q801,

Q802, ZD802,

VR801

Normal

(68 V, 31.5 kHz)

Check voltage of

cathode, heater,

Grid 1, Grid 2, etc.

Check D801,

D802, D803, D804, T801,

R804, F801

High

(75 V or more)

Check I401,

R4F6, R4F5, R4C4

5-2 OSD Abnormal

VM77S

OSD Abnormal

Check I502 pin 9, 4

is 5V and pin 5, 10, 7, 8

missing?

Check R517, L514,

R527, R523, R524

OK?

Yes

Check P502

OK?

Yes

Put on

I502

Replace them

Replace it

Yes

Replace I502

5-3 Function Key Abnormal

Replace I703 or do

Function Key Abnormal

VM77S

Check I701 and

I703 missing?

Power

ON/OFF again and

check X701, oscillator

OK?

Yes

Check

I703 EEPROM content

OK?

Yes

Put on

I701, I703

Replace X701

ATE again

Replace I701 and check

uP OK?

Check

pin 8 of I701

is 5V?

Replace I705, Q701,

Q702, R728

Yes

Replace I701

Check

ZD709, R735

5-4 No Vertical Scan (Raster is one horizontal line)

Ckeck or replace

Check R312, R307,

No Vertical Scan

Check I301 voltage of pin 1 is 12V, pin 4 is

-12V, pin 2 is 35V?

Yes

VM77S

I301.

Check

pin 5 O/P waveform at

I301

Yes

Check

pin 6, 7 of I301

waveform

Still no vertical scan

Check or replace CRT

R306, R313

Replace I401

5-5 Out of Horizontal Synchronization

Check or replace

the signal cable or

H. sync pin 41

Check or replace

Check signal cable

& V. sync pin 42

Check or replace

Out of Horizontal

Synchronization

Horizontal

sync present at

pin 15 of I401

Yes

Check

I401 pin 8 H. output

frequency & pin 29

waveform

VM77S

of I701.

I401, C406

Yes

Check Q401,

T401, Q402,

R424, D401

5-6 Out of Vertical Synchronization

Out of Verizontal

Synchronization

Verizontal

sync present at

pin 14 of I401

Yes

of I701.

Check

I401 pin 24 waveform

Yes

Check I401 pin 13 & pin 14.

C303, I401,

5-7 R.G.B. Video Amplifier Abnormal

Check or replace the

signal cable or I501

RGB Video AMP Abnormal

VM77S

waveform at I501 pin 5, 6 and

Check

Yes

Check

I502 pin 1, 2 and 3 collector

voltage (normally about 70V)

& waveform

Yes

Video signal present at the

pin of the CRT R.G.B.

Cathode

Yes

Defective cut-off circuit

(DC restore) I504

Check I901

VM77S

6 Recommended Parts List

Note:1. The components identified by “ “ mark are critical for X-ray safety. Replace these with

exactly the same parts specified.

No. Location Part Number Description

1 Q401 6421002705 TR NPN KSD1616A G TA 2 C808 6312618102 ALU uF 180 400V F 85C 25x35

4 D814 6412021702 DIODE FE30-02BXF06

5 D810 6412004117 DIODE UF2004M 2A/200V 50 nS 6 D815 6412002617 DIODE UF3002M 3A/100V 50 nS

7 D817 6412024404

8 F801 6851504053 FUSE TIME LAG H-BRK 4A/250V 9 I301 6442026400 IC TDA4863J 7P (PHILIPS)

10 I401 6442030000 IC TDA4841 32P SDIP (PHILIPS)

11 I501 6442031500 IC LM 1267 24P SDIP (NS)

12 I502 6442029700 IC LM2469 9P NS 13 I503 6442029900 IC LM2479 8P NS 14 I701 6448014500 IC MTV212 M(A) S32 40P PDIP MYSON 15 I703 6448015720 IC MTV24C08 (MYSON) 16 I705 6442000875 IC KIA78L05 (SAMSUNG) 17 I801 6442031600 IC 5S 0765C 5P FAIRCH

D801 D802 D803 D804

6412010907 DIODE LT2A06 T52 2A/800V

DIODE HER106 1A/600V 50 nS

18 L404 6111274130 COIL CHOKE 2.7mH K DR8x10 19 L405 6119007701 COIL LINEAR 20 L409 6111155133 COIL CHOKE 150uH DRWW 14x15 LY3B 21 L410 6111155138 COIL CHOKR L=150uH K DRWW 14x15 22 Q402 6421004900 TR NPN 2SC5387

23 Q418 6422002925 TR NPN HBF422T/B TO-92 TAPING

24 Q419 6422006000 TR NPN 2SD2012 TO-220(IS)

Q420 Q421 Q430

6426010500 (S0) 6426006400 (S1)

FET N-CHNL IRF630MFP/IRFS630A

No. Location Part Number Description

24 Q419 6422006000 TR NPN 2SD2012 TO-220(IS)

VM77S

26 Q451 6426006300 FET N-CHNL IRFS634A FAIRCH 11d 27 R803 6203080017 POSISTOR & OHM DGC2R08M 28 R804 6201100012 THERMISTOR 10 OHM 3A P=5 UEI 29 R802 6221127852 MOF OHM 0.27 1W J HOR 30 R4E3 6221227852 MOF OHM 0.27 2W J HOR 31 T401 6135000801 XFRMER HOR DRIVE THD-1008A EI19

32 T402

33 T403

34 T801 6138001603 LINE FILTER TLF-1016C 16mH LSE

35 T802

Q420 Q421 Q430

6426010500 (S0) 6426006400 (S1)

6133070190 6133070200

6136001300 6136001301

6131042221 6131042231

FET N-CHNL IRF630MFP/IRFS630A

FBT TFB-7019 FEA953 SAMPO (S0) FBT TFB-7020 CF1837 LIEN CHANG (S1)

XFRMER DYNAMIC TDF-1012 EI19LSE (S0) XFRMER DYNAMIC TDF-1013 EI19HJC (S1)

XFRMER PWR TPW-1084A ERL35 LSE (S0) XFRMER PWR TPW-1084A ERL35 HJC (S1)

36 X701 6449006900 CRYSTAL 12.000 MHZ 49U 30PF TOP

SDA

SCL

P501

O/R

R DAC

G DAC

B DAC

H V

LED

SDA SCL

OSD BLK R G B

KEY

CONTROL

S702

O/R

V H

SDA

SCL

PRE AMP

I501

LM1267

B 5V

OSD

MTV021

SDA

I701

MTV212M(A) 32

ABL

SCL

LM2479 BUFFER

RESTORE

SW 5 V

6.3V

GND

R, G, B

GND

SDA 1 SCL 1

115V

V H

80V

Video AMP

LM2469

80V 11.6V

P503

11.6V

BLANKING

I401

TDA4841

I502

CKT

ABL

GND

BRIGHTNESS

CONTROL &

SPOT KILLER

DRIVER

CLBL

HFLB

R432

SDA1

OUT

SCL1

SW5 V

VTTL

GND

VIDEO 5 V

HFLB

GND

DIODE

MODULATE

P502

25.6KV

FBT

-150V 650V

6.6KV 115V

POWER

DEL CKT

Q701, Q702

5W SW CKT

E2PROM

I703

LINE

FILTER

BRIGHTNESS

I705

78L05

DEG CKT

BRIDGE

DIODE

Q805

LOW VOLTAGE

DROP DOWN

-12V

5S0765C

I801

SMPS

POWER

O/P

TRANS

T802

VERTICAL

O/P

I301

TDA4863J

12V

11.7V

Q813

6.3V Q811

80V

Vertical Focus

XRP

Q805

STEP

CKT

dynamic

foucus

650V

-H D.Y

-V

Tatung TUK-VM77S Schematic

Specifications and Main Features

Frequently Asked Questions

User Manual