AOC Spectrum 7V Series User manual

SERVICE MANUAL
COLOR MONITOR
SPECTRUM 7V SERIES
(S761U/V)
41AS761-E11

2
TABLE OF CONTENTS
PAGE
1. SPECIFICATIONS .....................................................................................................
3
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
5. CIRCUIT DESCRIPTION ..........................................................................................
12
5-1 MICRO CONTROLLER CIRCUIT .............................……………………... 12
5-2 DEFLECTION CIRCUIT .............................………………………………... 13
5-3 TRANSISTOR & DIODE CIRCUIT .............................……………………. 14
6. TROUBLE SHOOTING CHART ..............................................................................
15
6-1 NO RASTER, CRT RELATIVE CIRCUIT PROBLEMS .............................. 15
6-2 ABNORMAL DISPLAY ................................................................................. 17
6-3 NO BLANKING .........................................................................................…. 18
6-4 HOR. /OSC /DEF /HV CIRCUIT FAULT ...................................................... 18
6-5 ABNORMAL HORIZONTAL DEFLECTION .............................................. 19
6-6 ABNORMAL VERTICAL SCANNING ........................................................ 20
6-7 SIDE-PIN CUSHION DISTORTION ............................................................. 20
6-8 POOR FOCUS ................................................................................................. 20
6-9 POWER SUPPLY TROUBLE SHOOTING CHART .................................... 21
7. MECHANICAL OF CABINET FRONT DIS-ASSEMBLY......................................
22
8. PARTS LISTING .......................................................................................................
23
9. BLOCK DIAGRAM .....................................................................…………………..
41
10. IC BLOCK DIAGRAMS............................................................................................
43
11. PCB LAYOUT ............................................................................................................
48
12. SCHEMATIC DIAGRAM .........................................................................................
50

3
1. SPECIFICATIONS FOR 7V SERIES COLOR MONITOR
1. CRT : 43.2CM(17") 90 Deflection, 29mm Neck, 0.27mm Dot Pitch, Non-Glare Screen
2. Viewable image Size: 40.6CM (16") diagonal
3. Display Color: Unlimited Colors
4. External Controls:
Power On/Off, OSD key, Function knob: Contrast, Brightness, H-Size, H-Center, V-Center, V-Size, ZOOM,
Pincushion, Trapezoid, Pin-Balance, Parallelogram, Rotation, Color Temperature, Degaussing, Moire Reduce,
Recall, Language.
5. Input Video Signal
Mode 1 Mode 2 Mode 3 Mode 4 Mode 5 Mode 6
RGB Analog
RGB Analog RGB Analog RGB Analog RGB Analog RGB Analog
Horiz. Sync: TTL Level TTL Level TTL Level TTL Level TTL Level TTL Level
Negative Negative Negative Positive Positive Positive
Vert. Sync: TTL Level TTL Level TTL Level TTL Level TTL Level TTL Level
Negative Positive Negative Positive Positive Positive
Horizontal: 640 (H) 720 (H) 640 (H) 800 (H) 1280 (H) 1024 (H)
Vertical : 480 (V) 400 (V) 480 (V) 600(V) 1024(V) 768 (V)
Fh (KHz): 31.47 31.47 43.3 53.67 64.0 68.6
Fv (Hz) : 60 70 85 85 60 85
6. Display Size
Horizontal: 300 mm
Vertical: 230 mm
7. Scanning Frequencies
Horizontal: 30KHz ~70KHz
Vertical: 50 Hz ~130 Hz
8. Factory Preset Timings: 6
User Timings: 8
9. Misconvergence
Center: 0.3 mm Max.
Corner: 0.4 mm Max.
10. Video Bandwidth: 110 MHz

4
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
14. Weight: 15.5 Kgs(Net), 17.5Kgs(Gross)
15. Dimensions Monitor:
Carton: 495(W) × 455(H) × 525(D) mm
Monitor: 410(W) × 402(H) × 420(D) mm
16. External Connection:
15 Pin D-type Connector
AC Power Cord
17. Regulations:UL, CSA, FDA, FCC, TÜV/GS, CE, MPR-II, TCO’95 or TCO’99

5
2. PRECAUTIONS AND NOTICES
2-1SAFETY 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. 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.
(c) Reverse the AC plug at the AC outlet and repeat AC voltage measurements for each exposed metallic 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.
2-2PRODUCT 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.
2-3SERVICE 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.

6
2-4HIGH 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
24.5KV ±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 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 10K 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.

7
3. OPERATING INSTRUCTIONS
This procedure gives you instructions for installing and using the 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:
15 -Pin Color Display Signal Cable
PIN NO.
DESCRIPTION
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-R14. VERT. SYNC ( VCLK)
7. GND-G15. 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 color display requires service, it must be returned with the power cord.
1
6
11 15
5
10

8
4. ADJUSTMENT
4-1ADJUSTMENT 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.
4-2MAIN ADJUSTMENTS
NO.
FUNCTION LOCATION DESIGNATION
1. 14V ADJ PCB -MAIN VR903
2. B + ADJ PCB -MAIN VR902
3. SCREEN ADJ FLY BACK TRANS T402
4.H-FOCUS ADJ FLY BACK TRANS T402
5. V-FOCUS ADJ FLY BACK TRANS T402
6. ABL ADJ PCB -MAIN VR701
-MENU PCB -MAIN SW101
-UP PCB -MAIN SW102
7. FUNCTION ADJ -DOWN PCB -MAIN SW103
-EXIT PCB -MAIN SW104
4-3ADJUSTMENT METHOD
1. 14V, B + & HV voltage adjustment:
A. Chroma-2000 Signal generator or PC equivalent set mode 1, VGA 640X480 pattern 1.0 .
B. Connect a DC Volt meter between TP901 and ground, then adjust VR903 to be 14VDC.
C. Connect a DC Volt meter between TP902 and ground, then adjust VR902 to be 59.5 VDC.
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. Then press the
Up/Down Key to adjust its value for the optimum picture.

9
080
Factory Preset
9300 6500
CONTRAST H-MOIRE REDUCE
BRIGHTNESS V-MOIRE REDUCE
H-CENTER R-GAIN
H-SIZE G-GAIN
V-CENTER B-GAIN
V-SIZE R-BIAS
ZOOM G-BIAS
PINCUSHION R-BIAS
TRAPEZOID 9300 COLOR TEMPERATURE
PIN-BALANCE 6500 COLOR TEMPERATURE
PARALLELOGRAM DEGAUSS
ROTATION OSD EXIT
CORNER RETURN
H:31.4KHZ
V:59.8HZ

10
D. To switches the input signal to the other Timing Mode. Please follow step A ~ C to get the optimum picture.
E. 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)
F. 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.
3. White Balance, Luminance adjustment:
A. Bias (Low Luminance) adjustment:
(a) Set mode 1 640×480 Fh: 31KHz full white pattern.
(b) To make the adjustment condition is under the Factory preset window.
Same as step 2-B.
(c) Warm up more than 20 minutes.
(d) Brightness set to maximum. Contrast set to min. full white pattern, then adjust FBT screen VR to
make Y= 4.5±0.5cd/m²
(e) Brightness set to raster just cutoff, adjust contrast to be 4FL, then adjust G-Bias , B-Bias , R-
Bias , to make the setting value is(50), then adjust the R.G.B Bias individual to the color
temperature x= 283 ±10, y= 297 ±10.
B. Gain (High light) adjustment:
(a) Set mode 1 640×480 Fh: 31.5KHz full white pattern.
(b) Brightness set to raster just cutoff and set the contrast to max.
(c) Adjust G-Gain , B-Gain , R-Gain , to make color temperature x=283 ±10, y=297 ±10.
(d) Change to 20% window white pattern then adjust contrast to 148±2cd/m².
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.
E. Full white luminance:
(a) Set mode 1 640×480 Fh: 31.5KHz full white pattern.
(b) Image Size : H:300±4mm V:230±4mm.
(c) Brightness set to raster just cut off and set the contrast to max.
(d) Adjust VR701 to the luminance at 92±2cd/m².
4. Focus Adjustment:
A. Set mode 1 640×480 Fh: 31.5KHz with character full page.
B. Adjust brightness to center 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.

11
RELATIVE PLACEMENT OF TYPICAL COMPONENTS
Purity Magnets
Deflection Yoke
4-pole Convergence Magnets
6-pole Convergence Magnets
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.

12
5. CIRCUIT DESCRIPTION
5-1MICRO CONTROLLER CIRCUIT
MICRO Controller
The IC101 contains a 6502 8-bit CPU core, 512 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 V-sync
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. Pin39/Pin40 are for the H-SYNC and V-SYNC input, Pin32/Pin33
will output the same signal as input sync signal without delay, and the polarity are setting in the positive. When no signal
input, the Pin32 will output a 61Hz V-SYNC free run signal. The Pin33 will output a 62.5KHz H-SYNC free run signal.
for the monitor testing use.
On Screen Display Controller
The IC105 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.
Pin2 is used to control the internal oscillator frequency by DC voltage input from external low pass filter (R154, C166,
R155) and filter (R175, C167) 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, ²bus 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.

13
5-2DEFLECTION CIRCUIT
The deflection circuit is achieved by a high performance and efficient solution IC 401 (TDA9111) for this monitor. The
concept is fully DC controllable and can be used in applications with a micro-controller solutions.
The TDA9111 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 1nF C447 at pin5. The free running frequency is
determined by a resistor R410 4.7K form pin6 to ground.
PLL 1 Phase Detector
The phase detector is a standard one using switched current sources. It compares the middle of H-sync. with a fixed
point on the oscillator saw-tooth voltage. The PLL loop filter C435, C437, R411, D403 is connected to Pin7.
PLL2 Phase Detector
This phase detector is similar to the PLL1 detector and compares the line flyback pulse at pin 12 with the oscillator saw-
tooth voltage. The PLL2 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 pin4.
X-ray Protection
The X-ray protection input pin25 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:
Pin28 (BDRV) is floating
Pin26 (HDRV) is floating
Pin21, 23 ( VOUT 1, 2) are floating
Vertical Oscillator
The vertical free –running frequency is determined by the resistor C613, C616, R616 at pin22. Usually the free-running
frequency should be lower than the minimum trigger frequency.

14
5-3 TRANSISTOR & DIODE CIRCUIT
LOCATION
CIRCUIT FUNCTION DESCRIPTION
D901 ~ D904 Bridge Rectifier for AC Source
D910 Clamp Diode for Snubber CKT
D918, D919 Rectifier for Output Voltage
D922 Rectifier for Output Voltage
D923 Rectifier for Output Voltage
D925 Rectifier for B+ Supply
D929 B+ Feed Back Rectifier from F.B.T Pulse
Q901 MOS FET for Switching Power Control.
Q907, Q908 Use for Off-Mode to Cut-off 6.3V Supply Voltage
Q909, Q910 Use for Standy-By or Suspend Mode to Cut-off 14V Supply Voltage
Q912, Q920 Push-Pull Topology to Drive Q911
Q913 Degaussing Switcher Transistor
Q921 5V Regulator Transistor
Q401 Turn-on at Power ON/OFF and Change Mode to Protect Hor.Block
Q402 HOR. Driver Transistor
Q407, Q408 As a Switcher for Horizontal S Correction CKT
Q426 Horizontal s correction control MOSFET
Q404, Q405 As Differential Amp. to Drive Q406
Q406 Transistor for H-Size Control
Q705 Brightness Control CKT and as a Switch to Mute Screen.
Q741, Q742 V-Dynamic focus CKT
Q821 ~ Q823,
Q830 ~ Q832 Video DC Restoration control transistor

15
6.TROUBLE SHOOTING CHART
6-1 NO RASTER, CRT RELATIVE CIRCUIT PROBLEMS
REFER ITEM S.M.P.S.
BRIGHTNESS SET TO MAX. THEN
CHECK CRT G1 VOLTAGE
NG
NG
NG
NG
NG
OK
OK
OK
OK
OK
CHECK THE HIGE VOLTAGE
CHECK THE VOLTAGE OF CRT
HEATER ABOUT 6.3V
CHECK VOLTAGE OF THE CRT
CHECK BRIGHTNESS CIRCUIT
OK
CHECK POWER SAVING CIRCUIT,
"ABNORMAL DISPLAY"
H-SYNC, V-SYNC SIGNAL
CHECK SCREEN VOLTAGE ABOUT
LESS THAN 300V CHECK FBT
CHECK MAIN PCB POWER SUPPLY
CHECK FAILSAFE CKT IC401
Q909, Q910
CHECK CRT'S HEATER RELATIVE
CIRCUIT Q907, Q908
Q703, Q704, Q705 RELATIVE CKT.
PIN 25 RELATIVE CKT.
OF CRT ABOUT 24.5 ~ 25.5KV
400V TO 600V
REFER ITEM 6-2
53V, 14V, 78V
CATHODE ABOUT 55V TO 65V
CHECK THE HIGE VOLTAGE OF
CRT ABOUT 24.5+-1.0KV
CHECK SCREEN VOLTAGE ABOUT
450V TO 650V
CHECK BRIGHTNESS CIRCUIT
Q704, Q705 RELATIVE CKT.

16
2.ABNORMAL VIDEO LEVEL ON SCREEN
OK
NG
OK
NG
NG
OK
OK
CHECK THE VOLTAGE OF IC801
CHECK THE SIGNAL INPUT OF R.G.B.
ABOUT 0.7Vpp
CHECK THE VIDEO OUTPUT OF IC801
R.G.B. APPROACH STANDARD
CHECK SIGNAL CABLE OR
INTERFACE CARD.
CONTRAST SET MAX.
PIN 2, 16 ABOUT 8V
CHECK 8V RELATIVE CIRCUIT
CHECK THE IC801 PIN 11
RELATIVE CIRCUIT
RELATIVE CIRCUIT
CHECK IC801 PIN 11 CLAMP PULSE
PIN 13, 15, 18 ABOUT 4Vpp,
CHECK IC801 PIN 3/PIN 5/PIN 8 & PIN 10
3. ABNORMAL DDC (PLUG & PLAY)
OK
NG
CHECK IC101 PIN 5 VOLTAGE ABOUT 5V
CHECK SIGNAL CABLE
CHECK Q921 GOOD OR FAIL
OR H802 PIN 2, 3 DATA OUTPUT

17
6-2 ABNORMAL DISPLAY
1.NO SIGNAL ON SCREEN
CHECK FBT RELATIVE CIRCUIT
LESS THAN 400V
OK
NG
NG
OK
OK
NG
OK
NG
CHECK THE OUTPUT VOLTAGE
CHECK THE B+ VOLTAGE OF
CHECK THE VOLTAGE OF CRT
CATHODE ABOUT 40Vpp
CHECK THE VOLTAGE OF FBT SCREEN
CHECK THE RELATIVE CIRCUIT
CHECK THE 12V PIN
OF SMPS ON MAIN PCB
RELATIVE CIRCUIT
OF P802 CONNECTOR
ABOUT 400V TO 700V
EXCEED 700V CHECK FBT & CRT RELATIVE CIRCUIT
CHECK VIDEO IC801 VCC ABOUT 8V
OF IC801 PIN 13, 15, 18 ABOUT 3Vpp
CHECK THE IC802
OF IC801 PIN 2/PIN 16 Vcc CIRCUIT
OR REFER ITEM 6-1
VIDEO PCB ABOUT 78V
CHECK THE 78V RELATIVE CIRCUIT
CHECK THE VOLTAGE OF FBT
SCREEN ABOUT 450V TO 650V
LESS THAN 450V

18
6-3 NO BLANKING
NG
OK
CHECK THE RELATIVE
CIRCUIT OF BLANKING
CHECK THE RELATIVE CIRCUIT
CHECK G1 RELATIVE CIRCUIT
CHECK R859 ON VIDEO PCB,
FBT PIN 5 ON MAIN PCB
OF Q601, Q707
6-4 HOR./OSC/DEF/HV CIRCUIT FAULT
1. NO RASTER (DISCONNECT WITH SIGNAL CABLE)
NG
OK
OK
OK
NG
NG
NG
CHECK THE COLLECTOR VOLTAGE
CHECK THE COLLECTOR VOLTAGE
RELATIVE CIRCUIT
RELATIVE CIRCUIT
CHECK Q402, T401
CHECK T401, T402, Q402, Q403,
ABOUT 3Vpp
OF Q403 ABOUT 1200Vpp AT FH:31KHz
D408, C418, C419, H-DY, B+
CHECK IC401 PIN 26 WAVE FORM
CHECK IC401 PIN 4~7, PIN 13
CHECK IC401 PIN 29 ABOUT 12 VDC
CHECK IC401 PIN 29 RELATIVE CIRCUIT
OF Q402 ABOUT 20Vpp
CHECK R858 ON VIDEO PCB, CHECK G1
RELATIVE CIRCUIT FBT PIN 5 ON MAIN
PCB.
CHECK THE RELATIVE CIRCUIT OF
Q705, Q708

19
6-5 ABNORMAL HORIZONTAL DEFLECTION
1. ABNORMAL HORIZONTAL WIDTH OF VIDEO
NG
OK
CHECK THE RELATIVE CIRCUIT
CHECK THE RELATIVE
CIRCUIT OF SMPS.
READJUST H-WIDTH FUNCTION
OF Q404, Q405, & Q406
CHECK THE HV OF
CHECK FBT B+ VOLTAGE
CRT ABOUT 25KV
ABOUT 60V AT FH=31KHz
2. ABNORMAL HORIZONTAL RASTER CENTER
CHECK D418, D419, R457, R458, L404
3. ABNORMAL HORIZONTAL VIDEO CENTER
RELATIVE CIRCUIT
CHECK IC401 PIN 4, 7
4. ABNORMAL HORIZONTAL LINEARITY
AND IC101 PIN 28, 29
CHECK L401, L403, Q426, RY401
CHECK THE HV OF CRT ABOUT
24.5KV

20
6-6 ABNORMAL VERTICAL SCANNING
1. ABNORMAL VERTICAL SIZE
OK
NG
OK
NG
READJUST V-SIZE FUNCTION VALUE
RELATIVE CIRCUIT
CHECK VERT. OSC CIRCUIT
RELATIVE CIRCUIT
NG
READJUST V-SIZE FUNCTION VALUE
CHECK THE VOLTAGE OF IC101
RELATIVE CIRCUIT
CHECK IC401 PIN 20, 21, 22, 23
CHECK THE IC601 PIN 2 ABOUT 11.8V
PIN 4 ABOUT -12V
CHECK D601, C605
2. VERTICAL CENTER
NG
READJUST V-CENTER
RELATIVE CKT
CHECK IC401 AND IC601
6-7 SIDE-PIN CUSHION DISTORTION
NG
READJUST SIDEPIN
CHECK IC401, Q404, Q405, Q406
RELATIVE CKT.
6-8 POOR FOCUS
READJUST FOCUS CONTROL
NG CHECK FOCUS CONTROL UNIT,
FOCUS LEAD WIRE, CRT SOCKET & CRT
This manual suits for next models
2
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