Color Monitor Service Manual
Contents
1. 2 Press the SELECT key to adjust RED GREEN and BLUE disappear L RECALL Do this by pressing the SELECT key the selected item should change from white to its own color e g RED goes to red color 3 Adjust the RED GREEN or BLUE using the UP DOWN key 4 Press the MODE key to finish the color adjustment The OSD should return to the Main Menu 5 Press the MODE key again to finish the adjustment The OSD will When you press the RECALL key all user adjustment values are erased and replaced by factory adjustment values TOVIS CO LTD TOVIS REV NO TOVIS P N MTG 1902EX DATE 2002 03 11 0 Color Monitor Service Manual PAGE 13 25 7 Adjustment Specification 7 1 Adjustment Sequence You should allow 15 minutes for the unit to warm up before adjusting 7 2 Adjustment Sequence FBT High Voltage gt G2 Voltage Raster Center gt Hor Size gt Hor Position gt Ver Size gt Ver position gt Side pin gt Trapezoid gt Focus gt White balance gt Convergence 7 3 Adjustment Procedure How to enter the Factory Mode Press SEL and UP key simultaneously 7 3 1 H V voltage adjustment 1 Input the cross hatch pattern with the 31KHz 640 480 mode 2 After connecting a HIGH voltage meter to the ANODE adjust VR 501 to 27kv 7 3 2 G2 Voltage adjustment 1 Input the cross hatch pattern wi2. ABL Automatic Beam Limiting The voltage of the FBT pin10 is affected by the anode current of the FBT When the voltage at pin 10 is decreased the anode current is increased accordingly When the anode current is increased contrast is set at the certain limited level 28FL in white pattern that is set by inner voltage of IC401 Video amplification section 8 8 1 Video pre amplifier IC401 Input video signals are amplified by means of IC401 and the amplified signals drive the video output stage C402 Video gain is adjusted by DC voltage at pin 12 for ABL control 8 8 2 Video output stage 402 The video output signal from 1C401 is amplified again by 402 and IC402 apply video signal to each cathode of CRT Q405 Q406 and Q407 which is operated by I2C BUS control through u com adjust cutoff voltages 8 8 3 OSD On Screen Display 403 The OSD signal is applied from IC403 to IC402 It is controlled by BUS control line TOVIS CO LTD TOVIS TOVIS P N MTG 1902EX DATE 2002 03 11 REV NO 0 Color Monitor Service Manual PAGE 20 25 9 TROUBLE SHOOTING 9 1 NO POWER NO POWER YES CHECK IC105 7 WAVEFORM CHECK IC101 3 WAVEFORM CHECK amp REPLACE F101 POWER CORD CHECK amp REPLACE BD101 CHECK amp REPLACE IC105 NO CHECK amp REPLACE TOVIS TOVIS P N MTG 1902EX DATE 2002 0311
3. REV NO 0 Color Monitor Service Manual PAGE 21 25 9 2 NO VIDEO y CHECK SIGNAL CABLE CHECK 8 REPLACE SIGNAL CABLE CHECK IC401 21 24 26 PULSE YES CHECK IC401 NO 23 DC LEVEL amp 3118 19 PULSE CHECK amp REPLACE IC601 Q204 CHECK amp REPLACE 401 Y CHECK IC402 1 3 5 PULSE CHECK amp REPLACE TES IC402 CHECK amp REPLACE CRT SOCKET G1 TOVIS CO LTD TOVIS P N MTG 1902EX DATE 2002 0311 TOVIS REV NO 0 Color Monitor Service Manual PAGE 22 25 9 3 NO RASTER y NO y MES CHECK Q319 WAVEFORM CHECK 8 REPLACE FBT CRT CHECK G1 8 DC 80V NO CHECK Q319 BASE CHECK 8 REPLACE Q507 CHECK 8 REPLACE Q313 0311 D312 CHECK 8 REPLACE Q307 Q309 Q310 TOVIS CO LTD TOVIS TOVIS P N MTG 1902EX DATE 2002 03 11 REV NO 0 Color Monitor Service Manual PAGE 23 25 9 4 TROUBLE IN HORIZONTAL SIZE H SIZE NO POWER CIRCUIT CHECK Q352 YES DRAIN WAVEFORM CHECK 8 REPLACE Q308 D308 V CHECK IC301 28 WAVEFORM CHECK amp REPLACE IC301 CHECK amp REPLACE Q353 354 TOVIS CO LTD TOVIS TOVIS P N MTG 1902EX DATE 2002 0311 REV NO Color Monitor Service Manual 0 PAGE 24 25 9 5 TROUBLE
4. TOVIS TOVIS P N MTG 1902EX DATE 03 11 02 REV NO 0 IGT P N 69925601 PAGE 1 25 Color Monitor Service Manual MODEL MTG 1902EX TOVIS CO LTD E ovis Total Visual Appliance TOVIS P N MTG 1902EX DATE 2002 03 11 TOVIS Color Monitor Service Manual a PAGE 2 25 INDEX 1 SAFETY PRECAUTIONS 3 2 SPECIFICATIONS 4 3 TECHNICAL FEATURES 5 TIMING A rni ente 6 SETUP oo 7 6 CONTROLS AND ADJUSTMENTS 8 7 ADJUSTMENT SPECIFICATIONS 13 8 DESCRIPTION OF CIRCUIT OPERATION 16 9 TROUBLE SHOOTING 20 TOVIS CO LTD TOVIS P N MTG 1902EX DATE 2002 03 11 TOVIS REV NO 0 Color Monitor Service Manual PAGE 3 25 1 SAFETY PRECAUTION WARNING Service should not be attempted by anyone unfamiliar with the necessary precautions set forth in this manual Please adhere to these service precautions 1 1 Some parts in this unit such as the picture tube have special safety related characteristics for X RAY RADIATION protection For continued safety parts replacement should be undertaken by referring to articles 1 2 1 5 1 2 Many electrical mechanical parts in this unit have special safety related characteristics for protection against electrical shock and other potential hazard
5. BUS control 3 Horizontal driver output The output pulse which has the duty cycle of 47 is available at pin 26 of IC301 This output is used for horizontal drive circuit 4 B control driver output The output pulse is available at pin 28 of IC301 and it is used for H scan voltage control driver 5 X ray protection When the fly back voltage rises up to an unacceptable level x ray protection is activated X ray input pin 36 of ic601 is above 3 2v This result is that complete line drive stage stops working The reset of this protection is obtained by Main power off 8 2 2 Vertical section 1 Vertical oscillation The free running frequency of the vertical oscillator is determined by the capacitor C342 at pin VCAP pin22 of IC301 2 Vertical amplitude Vertical amplitude is controlled by IC601 using C 3 Vertical position Vertical position is controlled by IC601 using TOVIS P N MTG 1902EX DATE 2002 03 11 TOVIS CO LTD TOVIS P N MTG 1902EX DATE 2002 03 11 TO VIS PAGE 18025 4 Ease west parabola A parabola waveform is available on pin 24 of IC301 for driving the pincushion correction stage Amplitude of parabola waveform is controlled by IC601 using 8 2 3 B Regulator B PWM regulator output is available on pin 28 of IC301 for driving the B control stage 8 3 Vertical Deflection IC201 8 4 IC201 KA2142 is used for direct driving of
6. CONTROLLER SENSOR GLASS UNDERSIDE OF CONTROLLER NetGND 13VDC Gnd RED Video Gnd Green Video Gnd Blue Video Gnd SHIELD Ring Lug to Chassis H sync V sync 120 Clk l2C SDA Main Bd Power Input Connector 11 18 3 2 P5 66 18 1 55 18 Er Ring Lug to Chassis AC line AC Neutral FRAME GND 23 TOVIS CO LTD TOVIS TOVIS P N MTG 1902EX Color Monitor Service Manual REV NO DATE 2002 03 11 PAGE 6 CONTROLS AND ADJUSTMENTS There are four switches on the control panel Adjustable controls allow the best display status for individual preferences 6 1 Key Function MODE MODE Call the Main Menu OSD SEL DEGAUSS SEL Select the function sub Menu OSD on the Main Menu OSD DEGAUSS perform degaussing if the OSD is not displayed DOWN UP SW102 SW104 SW101 SW103 O O O O O O UP DOWN SEL MODE O S D Control Sub P C B When the Main Menu is displayed you can search each function using these keys When the Sub Menu is displayed after you select the function you can change each state of the screen using these keys TOVIS CO LTD TOVIS P N MTG 1902EX DATE 2002 03 11 TOVIS REV NO 0 Color Monitor Service Manual PAGE 9 25 6 2 O S D CONTROL METHOD 1 Control items Brightness Contrast Horizontal Position Horizontal Size S
7. vertical deflection yoke Horizontal scan voltage control stage The step up converter is used in this stage The output pulse at pin 28 of the IC301 is synchronized on horizontal frequency And this pulse is operated via buffer stage Q353 Q354 This output is rectified through D308 C328 Horizontal deflection output stage 8 5 1 Line driver stage As a driver device small TR Q305 C3502E is used The driver transformer T302 is equipped with a snubber circuit R327 C309 at the primary side to damp excessive ringing 8 5 2 Horizontal power output stage The horizontal power output stage is used boost up circuit As a deflection transistor the Q308 J6820 is used To compensate the horizontal linearity theT301 is connected in a series with the horizontal DY It is controlled by DC collector voltage of Q304 which the base voltage of Q304 is integrated from output at pin 24 of IC601 TOVIS CO LTD TOVIS REV NO TOVIS P N MTG 1902EX DATE 2002 03 11 Color Monitor Service Manual PAGE 8 6 FBT Fly back Transformer As a driver device IC302 KA7500 is used The high voltage for CRT anode focus G2 voltage for CRT and 800V for FOCUS VOLTAGE are generated by the FBT 8 8 Also 130V for G1 voltage 26V for X RAY detect voltage are extracted from the FBT In this way the supply voltage to the fly back transformer can be proportional to the horizontal line frequency
8. IN CONTRAST CONTRAST CHECK IC401 12 VOLTAGE NO CHECK 8 REPLACE m 401 401 18 WAVEFORM NO CHECK amp REPLACE IC601 CHECK amp REPLACE 401 TOVIS CO LTD TOVIS TOVIS P N MTG 1902EX DATE 2002 0311 REV NO 0 Color Monitor Service Manual PAGE 25 25 9 6 TROUBLE IN BRIGHTNESS CHECK amp REPLACE D318 CHECK POWER BOARD YES CHECK amp REPLACE Q507 TOVIS CO LTD
9. UB PCB OSD Control RL Vertical Size Side Pincushion Trapezoid Pin Balance Parallelogram VR control VR301 H MIN SIZE VR501 H V Adjustment MAIN PCB VR502 ABL Adjustment VR503 Sub Bright FBT Focus and Screen 6 3 OSD Controls User s control A BRIGHTNESS ADJUSTMENT 1 Press the MODE key then the Main Menu OSD should come out as below figure 2 Search the BRIGHTNESS sub menu by using the UP DOWN keys on the Main Menu OSD 3 Select the BRIGHTNESS by pressing the SEL key Then the BRIGHTNESS OSD color should change from yellow to red 4 Search BRIGHTNESS sub menu using the UP DOWN keys on the Main Menu OSD TOVIS CO LTD TOVIS TOVIS P N MTG 1902EX DATE 2002 03 11 REV NO 0 Color Monitor Service Manual PAGE 10 25 5 Select the BRIGHTNESS by pressing the SEL key Then the BRIGHTNESS OSD color should change from yellow to red 6 Adjust the Brightness as much as you want by using the UP DOWN keys 7 After finishing the Brightness adjustment press the MODE key then The BRIGHTNESS OSD color should change from red to yellow and be saved automatically 6 If you want to adjust other functions search your sub menu For example if you want to adjust the CONTRAST use the UP DOWN keys and then adjust the same way as item 3 4 and 5 7 To finish the adjustment press the MODE key t
10. eding this limit constitutes a potential shock hazard and must be corrected immediately TOVIS CO LTD TOVIS P N MTG 1902EX DATE 2002 03 11 TOVIS REVNO Color Monitor Service Manual PAGE 4 25 2 SPECIFICATION 2 1 Picture Tube Size 19 Dot Pitch 0 26mm 2 2 Signal Input Video Input Analog Positive Signal 0 7Vp p Horizontal Sync TTL Level Positive or Negative pulse e Scanning 28KHz 33KHz Vertical Input TTL Level Positive or Negative pulse Scanning 40 150Hz 2 3 Power Supply Power Input AC100 240V 50 60Hz Fuse Rating 250V 50T 3 15A Power Consumption Normal less than 85W DPMS less than 20W 2 4 External Control Refer to page 7 2 5 Operating Temperature 0 C 55 C 2 6 Operating Humidity 10 90 Non condensing 2 7 Net weight 17kg TOVIS CO LTD TOVIS REV NO TOVIS P N MTG 1902EX DATE 2002 03 11 0 Color Monitor Service Manual PAGE 5 25 3 TECHNICAL FEATURES 3 1 3 2 3 3 3 4 3 5 3 6 U com MCU control with OSD U com recognizes the computer signal and signal output from the control board connected with the wire Hence the circuit is simplified Universal AC input voltage The power supply operates on AC100 265volt 50 60Hz for global usage Protection Circuit When over current occurs in the circuit the protection c
11. hen the OSD will disappear BRIGHTNESS CONTRAST H POSITION H SIZE V POSITION V SIZE ROTATION PINCUSHION TRAPEZOID PARALLELG PIN BALANCE K COLOR k RECALL 640x480 60Hz 31 4KHz BRIGHTNESS CONTRAST H POSITIO lt gt o th H SIZE E I D Q V N V SIZE ROTATION PARALLEL K COLOR RECALL V POSITION PINCUSHION TRAPEZOID PIN BALANCE N G TOVIS CO LTD TOVIS P N MTG 1902EX DATE 2002 03 11 TOVIS REVNO 0 Color Monitor Service Manual PAGE 11 25 B CONTRAST ADJUST SAME WAY AS ABOVE C H POSITION ADJUST SAME WAY AS ABOVE D H SIZE ADJUST SAME WAY AS ABOVE E V POSITION ADJUST SAME WAY AS ABOVE F V SIZE ADJUST SAME WAY AS ABOVE G PINCUSHION ADJUST SAME WAY AS ABOVE H TRAPEZOID ADJUST SAME WAY AS ABOVE PARALLELOG ADJUST SAME WAY AS ABOVE J PIN BALANCE ADJUST SAME WAY AS ABOVE K COLOR ADJUSTMENT 1 Press the MODE key then Main Menu OSD come out as left below figure BRIGHTNESS CONTRAST H POSITION lt gt o th H SIZE E I DQ V N V POS ITION V SIZE ROTATION PINCUSHION TRAPEZOID PARALLELG PIN BALANCE 1 COLOR RECALL 640x480 60Hz 31 4KHz TOVIS CO LTD TOVIS TOVIS P N MTG 1902EX DATE 2002 03 11 REV NO 0 Color Monitor Service Manual PAGE 12 25
12. ircuit operates in order to prevent the components from electrical shock or other risks Override function The override function is designed for the normal display when the monitor is powered on without connection from a source No signal message Control panel If you are not satisfied with the factory mode size position or color settings use the control panel to program what you prefer in each resolution mode These adjusted settings are kept in memory even if you change resolution mode or turn off the monitor IC BUS control It is designed by C BUS control for simplifying circuit TOVIS CO LTD TOVIS TOVIS P N MTG 1902EX DATE 2002 03 11 REV NO 0 Color Monitor Service Manual PAGE 6 25 4 TIMING CHART Factory Pre Set Timing Modes PRA VIDEO A gt SYNC gt e A a Ble 6 DESCRIPTION MODE 1 MODE 2 VGA 720 400 VGA 640 480 31 469KHz 31 469KHz 31 778hs 31 778hs EX 3 813us 3 813ys H 1 907ys 1 589us IN 25 422us 25 422ys 0 636hs 0 318us o rms POL NEGATIVE VIDEO ANALOG TOVIS CO LTD TOVIS P N MTG 1902EX DATE 2002 03 11 TO VIS Color Monitor Service Manual ue i PAGE 7 25 5 SET UP 5 1 Start Up Your monitor starts up automatically when you insert the power plug into the power Source 5 2 25p AMP cable Connection AMP 25PIN MICROTOUCH MICROTOUCH DRAWER CONN
13. lines at the center of the screen Adjust the two tabs of 6 Pole Magnets to superimpose the red blue line with green one Adjusting the angle affects the vertical lines and rotating both magnets affects the horizontal lines Repeat adjustment Keeping in mind red green blue movement because 4 Pole Magnets and 6 Pole Magnets are interacted and make dot movement complex TOVIS CO LTD TOVIS P N MTG 1902EX DATE 2002 03 11 TOVIS REVNO 0 Color Monitor Service Manual PAGE 16 25 8 DESCRIPTION OF CIRCUIT OPERATION 8 1 Mode control 8 1 1 H Sync is inputted to pin 31 of IC601 V Sync to pin 30 of IC601 for each mode and pin 28 29 of IC601 output will always have positive polarity sync 8 1 2 The outputs from IC601 are as below See Table 1 Range of Frequency of Frequency OUT PUT MCU PIN Resolution Hf f CS1 CS0 dra kHz Hz Mi 39 40 41 me m ss EJ sepe Table 1 TOVIS CO LTD TOVIS P N MTG 1902EX DATE 2002 03 11 TOVIS REV NO 0 Color Monitor Service Manual PAGE 17 25 8 2 Deflection Processor IC301 8 2 1 Horizontal section 1 Horizontal oscillation R314 and C347 set horizontal free frequency Auto sync processing can be done from 30KHz to 7OKHz by means of IC301 without any adjustment 2 Phase shift Horizontal phase shift is controlled by IC601 using ZC
14. s These characteristics often go unnoticed by a visual inspection and the protection afforded by them cannot necessarily be obtained by using replacement components rated for higher voltage wattage etc Replacement parts which have these special characteristics are identified in the manual and highlighted on the schematic diagram and parts list Before replacing these components read the parts list carefully 1 3 When replacing chassis in the cabinet always be certain that all the protective devices are installed properly such as insulating covers strain relief etc 1 4 Before replacing the back cover of the set thoroughly inspect inside the cabinet to see that no stray parts or tools have been left inside 1 5 Before returning the set to the customer always perform an ac current leakage check on the exposed metallic parts of the cabinet such as terminal screw heads metal overlays control shafts etc To be sure the set is safe to operate without danger of electrical shock plug the AC power cable directly into a 115V AC outlet do not use a line isolation transformer during this check Use an AC volt meter with 5000 or more ohms per volt in the following manner You cannot use a 1500 ohm 10watt resistor paralleled by a 0 15 uF capacitor Reverse the AC plug the AC outlet and repeat the AC voltage measurements for each exposed metallic part Voltage measured must not exceed 0 3V RMS This corresponds to 0 2mA AC Any value exce
15. th 31KHz 640 480 mode 2 After connecting a DC high voltage meter to the G2 of the CRT socket adjust G2 voltage to 560V 10V by changing SCREEN VR of FBT 7 3 3 G D Adjustment Refer to controls and adjustment Article 6 7 3 4 Focus adjustment 1 Input the H character pattern with 31KHz 640 480 2 Adjust the focus for the best balance at each point of A B C D E as shown below by rotating the focus VR of FBT 3 4 2 4 1 4 1 4 2 4 3 4 TOVIS CO LTD TOVIS P N MTG 1902EX DATE 2002 03 11 TOVIS REV NO 0 Color Monitor Service Manual PAGE 14 25 7 3 5 White balance Adjustment Pre adjustment 1 This should be carried out for at least 15 minutes 2 Input the window pattern with 31KHz 640 480 mode 3 Degauss the screen with a manual degaussing coil White Balance adjustment Back Raster 1 Remove the video signal 2 Adjust the sub brightness of back raster to be 0 36 0 05FT L with R G B BIAS 3 And adjust the color temperature to be X 0 281 0 02 and Y 0 311 0 02 by R G B bias control function on OSD menu 4 Adjust BRIGHTNESS to be 0 36FL 0 05 F L White Balance adjustment Video 1 Input the 20 window pattern with 31KHz 640 480mode 2 Adjust the color temperature to be X 0 281 0 015 and Y 0 311 0 02 by R B gain on OSD menu 3 Adjust CONTRAST to be 67FL 5 FIL 7 3 6 Purity and Convergence Adjustment 1 Purity Adjustment Demagnetize
16. the picture tube and cabinet using a degaussing coil Turn the CONTRAST and BRIGHTNESS controls to maximum GAdjust the RED and BLUE bias controls to provide only a green raster Loosen the clamp screw holding the yoke and slide the yoke backwards to provide a vertical green belt zone in the picture screen Remove the Rubber wedges Rotate and spread the tabs of the purity magnet see figure 1 around the neck of the picture tube until the green belt is in the center of the screen At the same time center the raster vertically Move the yoke forward slowly until a uniform green screen is obtained Tighten the clamp screw of the yoke temporarily TOVIS CO LTD TOVIS TOVIS P N MTG 1902EX DATE 2002 03 11 REV NO Color Monitor Service Manual 0 PAGE 15 25 Check the purity of the red and blue raster by adjusting the bias controls Obtain a white raster referring to CRT GRAY SCALE ADJUSTMENT Proceed with convergence adjustment 2 Convergence adjustment Receive a crosshatch pattern with a color bar signal generator Adjust the BRIGHTNESS and CONTRAST Controls for a well defined pattern Adjust two tabs of the 4 Pole Magnets to change the angle between them and superimpose the red and blue vertical lines in the center area of the picture screen Turn both tabs at the same time keeping their angles constant to superimpose the red and blue horizontal
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