Ctx EX951F SERVICE MANUAL

SERVICE MANUAL

COLOR MONITOR

P993Z Series

EX951F

CTX

P/N : P993Z-3-00-A Date : Jun-02-03 Version : A00

THESE DOCUMENTS ARE FOR REPAIR SERVICE INFORMATION ONLY. EVERY REASONABLE EFFORT HAS BEEN MADE TO ENSURE THE ACCURACY OF THIS MANUAL; WE CANNOT GUARANTEE THE ACCURACY OF THIS INFORMATION AFTER THE DATE OF PUBLICATION AND DISCLAIMS LIABILITY FOR CHANGES, ERRORS OR OMISSIONS,

MANUFACTURE DATE : Jun. 2003

TABLE OF CONTENTS

PAGE

1. SPECIFICATIONS ..................................................................................................... 3-4

2. PRECAUTION AND NOTICES ................................................................................ 5

2-1 SAFETY PRECAUTIONS .............................................................................. 5

2-2 PRODUCT SAFETY NOTICE ....................................................................... 5

2-3 SERVICE NOTES ........................................................................................... 5

2-4 HIGH VOLTAGE WARNING ....................................................................... 6

3. OPERATING INSTRUCTIONS ................................................................................ 7

4. ADJUSTMENT .......................................................................................................... 8

4-1 ADJUSTMENT CONDITIONS AND PRECAUTIONS ............................... 8

4-2 MAIN ADJUSTMENTS ................................................................................. 8

4-3 ADJUSTMENT METHOD ............................................................................. 8-11

5. CIRCUIT DESCRIPTION .......................................................................................... 11-13

6. TROUBLE SHOOTING CHART .............................................................................. 14

6-1 NO RASTER, CRT RELATIVE CIRCUIT PROBLEMS .............................. 14-15

6-2 ABNORMAL DISPLAY ................................................................................. 16

6-3 NO BLANKING ........................................................................................... 17

6-4 HOR. /OSC /DEF /HV CIRCUIT FAULT ...................................................... 17

6-5 ABNORMAL HORIZONTAL DEFLECTION .............................................. 18

6-6 ABNORMAL VERTICAL SCANNING ........................................................ 19

6-7 SIDE-PIN CUSHION DISTORTION ............................................................. 19

6-8 POOR FOCUS ................................................................................................. 20

6-9 NO SOUND (FOR AUDIO MODEL ONLY)..................................…........... 20

6-10 POWER SUPPLY TROUBLE SHOOTING CHART .................................... 21

7. MECHANICAL OF CABINET FRONT DIS-ASSEMBLY...................................... 22

8. PARTS LISTING ....................................................................................................... 23-41

9. IC BLOCK DIAGRAMS............................................................................................ 42-46

10. PCB LAYOUT ............................................................................................................ 47-48

11. SCHEMATIC DIAGRAM ......................................................................................... 49

1. SPECIFICATIONS FOR 9Klr SERIES COLOR MONITOR

1. CRT : 46CM(19") 90 Deflection, 29mm Neck, flat 0.25mm Dot Pitch, Non-Glare Screen

2. Viewable image Size: 45.7CM (18") diagonal

3. Display Color: Unlimited Colors

4. External Controls: Power On/Off, OSD key, Function knob: Contrast, Brightness, H-Size, H-Center, V-Size, V-Center, ZOOM, Pincushion, Trapezoid, Pin-Balance, Parallelogram, Rotation, Moire Reduce, Recall, Degaussing, Color Temperature, Volume. (For 9KlrA Model)

5. Input Video Signal

Mode 1 Mode 2 Mode 3 Mode 4 RGB Analog RGB Analog RGB Analog RGB Analog

Horiz. Sync: TTL Level TTL Level TTL Level TTL Level

Negative Negative Negative Positive

Vert. Sync: TTL Level TTL Level TTL Level TTL Level

Positive Negative Negative Positive

Horizontal: 720 (H) 640 (H) 640 (H) 800 (H) Vertical : 400 (V) 480 (V) 480(V) 600(V) Fh (kHz): 31.327 31.469 43.269 53.750 Fv (Hz) : 69.616 59.9 85.008 84.997

Mode 5 Mode 6 Mode 7 Mode 8 RGB Analog RGB Analog RGB Analog RGB Analog

Horiz. Sync: TTL Level TTL Level TTL Level TTL Level

Positive Positive Positive Positive

Vert. Sync: TTL Level TTL Level TTL Level TTL Level

Positive Positive Positive Positive

Horizontal: 1024 (H) 1280 (H) 1280 (H) 1600 (H) Vertical : 768 (V) 960 (V) 1024 (V) 1200 (V) Fh (kHz): 68.677 85.935 91.148 93.75 Fv (Hz) : 84.997 85 85 75

6. Display Size

Horizontal: 346 mm Vertical: 260 mm

7. Scanning Frequencies Horizontal: Vertical:

30KHz ~ 98KHz 50 Hz ~ 160 Hz

8. Factory Preset Timings: 8 User Timings: 20

9. Mis-convergence Center: 0.3 mm Max. Corner: 0.4 mm Max.

10. Video Dot Rate: 200 MHz

11. Power Source: Switching Mode Power Supply AC 100 ~240V, 50/60Hz Universal Type

12. Operating Temperature: 0°C to 40°C Ambient

13. Humidity : 10% to 85% Relative, Non-Condensing

• Weight: 20.0 Kg (Net), 23.6Kg (Gross) for 9Klr

15 Dimensions Monitor:

Carton: 575(W) × 526(H) × 655(D) mm Monitor: 446(W) × 436(H) ×455 (D) mm for 9Klr

16. External Connection :

15 Pin D-type Connector AC Power Cord

17. Speaker: (for 9KlrA only) Rate power: 1.5W (per channel) Impedance:

8Ω

18. Regulations: UL, CSA, FDA, FCC, TÜV/GS, CE, TCO

Energy Star, MPR-II

2. PRECAUTIONS AND NOTICES

2-1 SAFETY PRECAUTIONS

1. Observe all caution and safety related notes located inside the display cabinet.

2. Operation of the display with the cover removed, may cause a serious shock hazard from the display power supply. 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 who are not so equipped should be kept away while handling picture tube. Keep picture tube away from the body while handling.

4. The picture tube is constructed to limit X-RAY radiation to 0.5 mR/HR. For continued protection, use the designated replacement tube only, and adjust the voltages so that the designated maximum rating at the anode will not be exceeded.

5. Symbol “ ” means safety relative parts. The use of substitute replacement parts which do not have the same characteristics as specified in the parts list may create shock, fire or explode etc.

6. Symbol “★” means important relative parts. Before replacing any of these components please read the parts list in this manual carefully to avoid creating higher anode voltage or x-ray. Especially for sealed controls, such as VR902, VR702 and FBT screen VR etc, which were sealed by the manufacturer once their optimum position has been set, please don’t dismantle them as your likes, otherwise you will break or damage the component. If you need replace the parts with sealed control, please adjust the relative VR to make sure the B+ voltage under 137.5Vdc at 1024*768@85Hz and well seal it with A+B glue or equivalent, which you can not move away with one screw driver.

7. 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, such as screw heads.

Test method for current leakage is described as follow. (a) Plug the AC line cord directly into rated AC outlet (do not use a line isolation transformer during this

check).

(b) Use an AC voltmeter having 5000 ohms per volt or with more sensitivity in the following manner:

Connect a 1500 ohms 10 Watt resistor, paralleled by a 0.15UF, AC type capacitor between a known good earth ground (water pipe, conduit, etc.) and the exposed metallic parts simultaneously. Measure the AC voltage across the combination of 1500 ohms resistor and 0.15UF capacitor.

part.

(d) Voltage measured must not exceed 0.5 volts RMS. This corresponds to 0.35 milliamp AC. Any value

exceeding this limit constitutes a potential shock hazard and must be corrected immediately.

2-2 PRODUCT SAFETY NOTICE

Many electrical and mechanical parts in this chassis have special safety visual inspections and 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.

2-3 SERVICE NOTES

1. When replacing parts or circuit boards, clamp the lead wires around terminals before soldering.

2. When replacing a high wattage resistor (more than 1/2W of metal oxide film resistor) in circuit board, keep

the resistor about 10mm (1/2 in) 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.

2-4 HIGH VOLTAGE WARNING

Operation of monitor outside of cabinet or with back removed may cause a serious shock hazard. Work on this model should only be performed by those who are thoroughly familiar with precautions necessary when working on high voltage equipment. Exercise care when servicing this chassis with power applied. Many B plus and high voltage terminals are exposed which, if carelessly contacted, can cause serious shock or result in damage to the chassis. Maintain interconnecting ground lead connections between chassis and picture tube dag when operating chassis. Certain HV failures can increase X-ray radiation. Monitor should not be operated with HV levels exceeding the specified rating for the chassis type. The maximum operating HV specified for the chassis used in this monitor is

26.5KV ± 1KV

with a line voltage of 120/240 VAC. Higher voltage may also increase possibility of failure in HV supply. It is important to maintain specified values of all components in the horizontal and high voltage circuits and anywhere else in the monitor that could cause a rise in high voltage or operating supply voltages. No changes should be made to the original design of the monitor. Components shown in the shaded areas on the schematic should be replaced with exact factory replacement parts. The use of unauthorized substitute parts may create a shock, fire or other hazard. To determine the presence of high voltage, use an accurate, high impedance, HV meter connected between second anode lead and CRT dag grounding device. When servicing the High Voltage System, remove static charge from it by connecting a 20K ohm resistor in series with an insulated wire (such as a test probe) between picture tube dag and 2nd anode lead.(AC line cord disconnected from AC power outlet.) The picture tube used in this monitor employs integral implosion protection. Replace with tube of the same type number for continue safety. Do not lift picture tube by the neck. Handle the picture tube only after discharging the high voltage completely.

3. OPERATING INSTRUCTIONS

This procedure gives you instructions for installing and using the 9K color display.

1. Position the display on the desired operation and plug the power cord into a convenient AC outlet. Three-

wire power cord must be shielded and is provided as a safety precaution as it connects the chassis and cabinet to the electrical conduit ground. If the AC outlet in your location does not have provisions for the grounded type plug, the installer should attach the proper adapter to ensure a safe ground potential.

2. Connect the 15-pin color display shielded signal cable to your signal system device and lock both screws

on the connector to ensure firm grounding. The connector information is as follow:

PIN NO.

DESCRIPTION

1. RED 9. NC

2. GREEN 10. GND

3. BLUE 11. SYNC. GND

4. GND 12. SDA

5. GND 13. HORIZ. SYNC

6. GND-R 14.

7. GND-G 15. SCL

8. GND-B

3. Apply power to the display by turning the power switch to the "ON" position and allow about thirty

seconds for display tube warm-up. The Power-On indicator lights when the display is on.

4. With proper signals feed to the display, a pattern or data should appear on the screen, adjust the brightness

and contrast to the most pleasing display.

5. This monitor has power saving function following the VESA DPMS. Be sure to connect the signal cable to

the PC.

6. If your 9K Series color display requires service, it must be returned with the power cord.

11 15

15 - Pin Color Display Signal Cable

PIN NO.

DESCRIPTION

VERT. SYNC (＊VCLK)

4. ADJUSTMENT

4-1 ADJUSTMENT CONDITIONS AND PRECAUTIONS

1. Approximately 30 minutes should be allowed for warm up before proceeding.

2. Adjustments should be undertaken only on those necessary elements since most of them have been carefully preset at the factory.

4-2 MAIN ADJUSTMENTS

NO. FUNCTION LOCATION DESIGNATION

1. B + ADJ PCB - MAIN VR902

2. SCREEN ADJ FLY BACK TRANS T402

3. FOCUS ADJ FLY BACK TRANS T402

4. ABL ADJ PCB - MAIN VR701

5. SUB-BRIGHTNESS ADJ PCB - MAIN VR702

4-3 ADJUSTMENT METHOD

1. B + & HV voltage adjustment and hold down circuit confirmation:

A. Chrome-2000 Signal generator or PC equivalent set mode 5, VGA 1024X768@85Hz pattern 1 . B. Connect a DC Volt meter between TP902 or D925 cathode and ground, then adjust VR902 to be

133VDC(B+).

C. Connect a DC Volt meter between TP701(G1) and ground, Brightness set to max. Then adjust VR702 to

be -30 VDC.

D. Connect a 22kΩ resistor in parallel with R419 to increase the HV, the hold down circuit will operate and

the display will disappear. Then disconnect this resistor to bring the unit to normal condition.

2. Factory preset Timings Adjustment:

A. Press MENU Key to show OSD window press Up or Down Key to switch the functional controls. B. Press the Up Key to select the "ZOOM" function, then press the MENU Key. While do not release the

MENU Key until the OSD window changed to the Factory preset window.

C. The Factory preset window contains the following functional controls. Select one of the control by press

MENU key. Then press the Up/Down Key to adjust it's value for the optimum picture.

MENU Key to Quit the OSD window. Mean while the new setting data will be saved in the memory.

E. To switches the input signal to the other Timing Mode. Please follow step C ~ D to get the optimum picture.

F. Select the "

" RETURN function and press the MENU Key, then the Factor Preset window will be

returned to the original OSD window.(user's operating condition)

G. The setting data of the CONTRAST, BRIGHTNESS, PIN-BALANCE, PARALLELOGRAM,

ROTATION, COLOR TEMPERATURE are common mode saved in the memory. Don't needed adjust it individual at every timing Mode and save in the memory.

Model select: for factory only, service engineer can't changed.

FACTORY PRESET

H: 68.8KHz V: 85Hz

H: 36.51kHz

V: 51.34Hz

HS HP

VcVs

9300

080

CONTRAST

BRIGHTNESS

H-CENTER

H-SIZE

V-CENTER

V-SIZE

ZOOM

TOP COMER

BOTTOM COMER

PINCUSHION

TRAPEZOID

PIN-BALANCE

PARALLELOGRAM

ROTATION

SUB-H-SIZE

H-SIZE-PHASE B/I ON/OFF

9300

6500

H-MOIRE REDUCE

V-MOIRE REDUCE

R-GAIN

G-GAIN

B-GAIN

R-BIAS

G-BIAS

R-BIAS

COLOR TEMPERATURE

DEGAUSS

OSD EXIT

RETURN

Vs LINEAR

Vc LINEAR

Used time

6500

3. White Balance, Luminance adjustment:

A. Bias (Low Luminance) adjustment:

(a) Set mode 5 1024 x 768 Fh: 68.7KHz full white pattern. (b) To make the adjustment condition is under the Factory preset window.

Same as step 2-C.

(d) Brightness

VR to make Y= 4.0±0.5cd/m

(e) Adjust G-Bias

set to maximum. Contrast set to min. full white pattern, then adjust FBT screen

, B-Bias , R-Bias , to make the setting value is(20), then adjust the

R.G.B Bias individual to the color temperature x= 265 ± 10, y= 290 ± 10, Y= 4.0±0.5cd/m

B. Gain (High light) adjustment:

(a) Set mode 5 1024 x 768 Fh: 68.7KHz full white pattern. (b) Brightness set to raster just cut off and set the contrast to max.

10, Y=140~150 cd/m

, B-Gain , R-Gain , to make color temperature x=283 ± 10, y=297±

C. Recheck item A&B to make sure both of them in spec. Finally select OSD function to the 9300°K function,

then press the MENU Key. To make the setting data saved in the memory.

D. The adjustment of 6500°K white Balance, May follow step A ~ C , with the x=313 ± 10, y=329 ± 10,

Y=140~150 cd/m

E. Full white luminance:

(a) Set mode 5 1024 x 768 Fh: 68.7KHz full white pattern. (b) Image Size : H:346±4mm V:260±4mm. (c) Brightness set to raster just cut off and set the contrast to max. (d) Adjust VR701 to the luminance at 90~95 cd/m

4. Focus Adjustment:

A. Set mode 5 1024 x 768 Fh: 68.7KHz with character full page. B. Brightness to cut off and contrast to max. C. Then adjust focus VR1 to a fine vertical line. D. Adjust focus VR2 to a fine horizontal line. E. Repeat step C & D..

5. Purity Adjustment

A. Be sure that the display is not being exposed to any external magnetic fields. B. Ensure that the spacing between the Purity, Convergence, Magnet, (PCM), assembly and the CRT stem is

29mm .(See below diagram)

C. Produce a complete, red pattern on the display. Adjust the purity magnet rings on the PCM assembly to

obtain a complete field of the color red. This is done by moving the two tabs in such a manner that they advance in an opposite direction but at the same time to obtain the same angle between the two tabs, which should be approximately 180'.

D. Check the complete blue and complete green patterns to observe their respective color purity. Make minor

adjustments if needed.

RELATIVE PLACEMENT OF TYPICAL COMPONENTS

Purity Magnets

6-pole Convergence Magnets

4-pole Convergence Magnets

Deflection Yoke

6. Convergence adjustment

A. Produce a magenta crosshatch on the display. B. Adjust the focus for the best overall focus on the display.

Also adjust the brightness to the desired condition.

C. Vertical red and blue lines are converged by varying the angle between the two tabs of the 4 pole magnets

on the PCM assembly. (See above diagrams)

D. Horizontal red and blue lines are converged by varying the two tabs together, keeping the angle between

them constant. E. Produce a white crosshatch pattern on the display. F. Vertical green and magenta lines are converged by varying the angle between the two tabs of the 6-pole

magnets. G. Horizontal green and magenta lines are converged by varying the two tabs together, keeping the angle

between them constant.

5. CIRCUIT DESCRIPTION

5-1 MICRO CONTROLLER CIRCUIT

MICRO Controller

The IC101 contains a 6502 8-bit CPU core, 256 bytes of RAM, 16K bytes of ROM,14 channel 8 bit PWM D/A converters, 2 channel A/D converters for key detection, one 8 bit pre-loadable base timer, internal H-sync and Vsync signals processor providing mode detection, watch- dog timer preventing system from abnormal operation, and an I2C bus interface.

H/V sync signals processor

The functions of the sync processor include polarity detection, H-SYNC & V-SYNC signals counting, Programmable SYNC signals output, free running signal generator. Pin41/Pin42 are for the H-SYNC and VSYNC input, Pin33/Pin34 will output the same signal as input sync signal without delay, and the polarity are setting in the positive. When no signal input, the Pin33 will output a 61HZ V-SYNC free run signal. The Pin34 will output a 62.5KHz H-SYNC free run signal. for the monitor testing use.

On Screen Display Controller

The IC804 is designed for display the built-in characters or fonts onto monitor screen. The display operation is by transforming data and control information from micro controller to RAM through a serial data interface. Pin 2 is used to control the internal oscillator frequency by DC voltage input from external low pass filter (R830, C811, R833) and filter (R126, C115) is used to regulate the appropriate bias current for internal oscillator the resonate at specific dot frequency. Pin5 is input the horizontal fly back pulse, for PLL generator tracking. Pin6 is left floating, I2C bus is enabled. Otherwise the SPI bus is enabled. Pin7 the external data transfer through this pin to internal display registers and control registers Pin8 the clock-input pin is used to synchronize the data transfer. Pin10 is input the vertical flyback pulse for synchronizing the vertical position. Pin12 is output a blanking signal to cut off external R.G.B signals of VGA while this chip is displaying characters or windows. Pin13, Pin14, Pin15 is used to output the OSD (B.G.R) video signal.

5-2 DEFLECTION CIRCUIT

The deflection circuit is achieved by a high performance and efficient solution IC 401 (UPC1888ECT) for this monitor. The concept is fully DC controllable and can be used in applications with a micro-controller solutions. The UPC1888ECT provides sync. Processing with full auto sync. capability, a flexible SMPS block and an extensive set of geometry control facilities. Further the IC generates the drive waveforms for DC coupled vertical boosters to the TDA9302H .

Horizontal Oscillator

The oscillator is of the relaxation type and requires a capacitor of 390nF C403 at pin 23. The maximum oscillator frequency is determined by a resistor R443 from pin 22 to ground.

PLL2 Phase Detector

This phase detector compares the line flyback pulse at pin 18 with the oscillator saw-tooth voltage. The HFL0 detector thus compensates for the delay in the external H-deflection circuit by adjusting the phase of the HDRV output pulses. The phase between H-flyback and H-sync can be controlled at pin21.

X-ray Protection

The X-ray protection input pin 19 provides a voltage detector with a precise threshold. If the voltage exceeds this threshold for a certain time, an internal latch switches the whole IC into protection mode. In this mode several pins are forced into defined states: Pin17 (HDRV) is floating Pin 12 (BDRV) is floating

Vertical Oscillator

The vertical free –running frequency is determined by the capacitor C604 at pin 2 and resistor R608 at pin20. Usually the free-running frequency should be lower than the minimum trigger frequency.

5-3 TRANSISTOR & DIODE CIRCUIT

LOCATION

FUNCTION AL DESCRIPTION

D101 For C102 Discharge

D405 Speed up for Q403

D406 Supply a bias for D408

D408 Damping Diode and Modulation Diode

D414~ D416,D418 Buffer Diode for Q412, Q417, Q418, Q420

Q401 B+ Mute Control

Q402 Horizontal Driver

Q403 Horizontal Out Put

Q404, Q406 A differential Amp for Drive Q405

Q405 Darlington Transistor for H-Size Control

Q407 Horizontal Linearity Correction Control

Q410,Q412,

Horizontal S-Correction Control Q417,Q418 D707 Mixing Diode

D704 Rectifier for 250V Supply

D709 Protection Diode for Q708

D706,D708 Rectifier for -200V Supply

Q707 Picture Mute Control AMP

Q703, Q706 Brightness Control CKT

Q708 Vertical Dynamic Focus Control AMP

DB901 Bridge Rectifier for AC Source

D918 ~ D919 Rectifier for Output Voltage Supply

D921 ~ D923 Rectifier for Output Voltage Supply

D924 Clip Diode for Trigger CKT

D925 Rectifier for B+ Supply

D926, D927 Raster Position Control

D939 Clip Diode for Snuffer Pulse

ZD901 Protection Diode

ZD903 Protection Diode

Q911 MOS FET for B+ Control

Q912, Q915 Push Pull Driver for Q911

Q914 Pre-Amplifier for Q912, Q915

Q850 ~ Q852 DC Restoration for CRT Bias Adjustment

6.TROUBLE SHOOTING CHART

6-1 NO RASTER, CRT RELATIVE CIRCUIT PROBLEMS

CHECK MAIN PCB POWER SUPPLY

CHECK MAIN PCB POWER SUPPLY 137.5V,14.5V,80V

60.5V, 14.5V, 80V

CHECK THE HIGE VOLTAGE

OF CRT ABOUT 25.5~27.5KV

OF CRT ABOUT 25.5 ~ 26.5KV

CHECK THE VOLTAGE OF CRT

HEATER ABOUT 6.3V

CHECK SCREEN VOLTAGE ABOUT 400V TO 700V

26.5~27.5KV

LESS THAN 300V

CHECK POWER SAVING CIRCUIT, H-SYNC, V-SYNC SIGNAL

REFER ITEM S.M.P.S.

CHECK FAILSAFE CKT IC401

PIN 2 RELATIVE CKT.

CHECK CRT'S HEATER RELATIVE CIRCUIT

CHECK FBT

BRIGHTNESS SET TO MAX. THEN CHECK CRT G1 VOLTAGE

CHECK VOLTAGE OF THE CRT

CATHODE ABOUT 60V TO 70V

CHECK BRIGHTNESS CIRCUIT

Q703, Q706, Q707 RELATIVE CKT.

REFER ITEM 8-2 "ABNORMAL DISPLAY"

2.ABNORMAL VIDEO LEVEL ON SCREEN

CHECK THE VOLTAGE OF IC801

7,15.18,21 ABOUT 12V

PIN 6, 9, 22 ABOUT 12V

CHECK THE SIGNAL INPUT OF R.G.B. ABOUT 0.7Vpp

CHECK IC801 PIN 15 CLAMP PULSE

PIN 16 BLANK PULSE

CHECK THE VIDEO OUTPUT OF IC801

16,19,22

PIN 18, 20, 23 ABOUT 4Vpp,

CONTRAST SET MAX.

R.G.B. APPROACH STANDARD

CHECK 12V RELATIVE CIRCUIT

CHECK SIGNAL CABLE OR INTERFACE CARD.

CHECK THE IC105 RELATIVE CIRCUIT

OR IC401 PIN 16 OUTPUT

CHECK IC801 PIN 13 ABOUT 4V PIN 26, 27, 28 ABOUT 4V OR CHECK Q801 AND RELATIVE CKT

1~24

3. ABNORMAL DDC (PLUG & PLAY)

CHECK IC101 PIN 5 VOLTAGE ABOUT 5V

CHECK Q102 GOOD OR FAIL

CHECK SIGNAL CABLE OR H802 PIN 3, 4 DATA OUTPUT

+ 37 hidden pages