Acer AF715 Series User manual

SERVICE GUIDE
COLOR MONITOR
(AF715 Series)
41AB793Z-ACER-A00
P/N : B793Z-01-A
Date: Mar-18-03
Ver : A00

1
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 : Mar. 2003

2
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 .......................................................................................... 11-14
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 ................................................................................................. 21
6-9 NO SOUND (FOR AUDIO MODEL ONLY)..................................…........... 21
6-10 POWER SUPPLY TROUBLE SHOOTING CHART .................................... 22
7. MECHANICAL OF CABINET FRONT DIS-ASSEMBLY...................................... 23
8. PARTS LISTING ....................................................................................................... 24
9. BLOCK DIAGRAM (DEFLECTION) ....................................................................... 42
10. IC BLOCK DIAGRAMS............................................................................................ 43
11. PCB LAYOUT ............................................................................................................ 47
12. SCHEMATIC DIAGRAM ......................................................................................... 49

3
1. SPECIFICATIONS FOR 7Klr SERIES COLOR MONITOR
1. CRT : 43.2CM(17") 90 Deflection, 29mm Neck, Pure flat 0.25mm 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-Size, V-Center, ZOOM,
Pincushion, Trapezoid, Pin-Balance, Parallelogram, Rotation, Moire Reduce,H-Convergence, V- Convergence
language select, Recall, Degaussing, Color Temperature.
5. Input Video Signal
Mode 1 Mode 2 Mode 3 Mode 4
R
GB 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: 640 (H) 720 (H) 640 (H) 800 (H)
Vertical : 480 (V) 400 (V) 480(V) 600 (V)
Fh (kHz): 31.47 31.47 43.3 53.67
Fv (Hz) : 60 70 85 85
Mode5 Mode 6 Mode7 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): 68.6 85.9 91.1 93.8
Fv (Hz) : 85 85 85 75
6. Display Size
Horizontal: 310 mm
Vertical: 232.5 mm
7. Scanning Frequencies
Horizontal: 30KHz ~96KHz
Vertical: 50 Hz ~160 Hz
8. Factory Preset Timings: 8
User Timings: 20
9. Misconvergence
Center: 0.3 mm Max.
Corner: 0.4 mm Max.
10. Video Bandwidth: 200 MHz

4
11. Power Source:
Switching Mode Power Supply
AC 100 ~240V, 50/60Hz Universal Type
12. Operating Temperature: 10 OC to 35OC Ambient
13. Humidity : 10% to 85% Relative, Non-Condensing
14•Weight: 17.0 Kgs(Net), 20.5Kgs(Gross)
15 Dimensions Monitor:
Carton: 570(W) × 530(H) × 540(D) mm
Monitor: 430(W) × 416(H) × 440(D) mm
16. External Connection :
15 Pin D-type Connector AC Power Cord
17. Regulations: UL, CSA, FDA, FCC, TÜV/GS, CE(For Europe Area or other required Area),
MPR-II,TCO’99

5
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 X-ray 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 VR901,
VR902, VR401 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
60.5KVdc 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.
(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.
2-2 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.

6
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
25.0KV ±0.3KV
with a line voltage of 100/240 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 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 7K 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. 5V
2. GREEN 10. GND
3. BLUE 11. SYNC. GND
4. GND 12. SDA
5. GND 13. HORIZ. SYNC
6. GND-R 14. VERT. SYNC (＊VCLK)
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 7K Series 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.
4-2 MAIN ADJUSTMENTS
NO. FUNCTION LOCATION DESIGNATION
1. HV ADJ PCB - MAIN VR703
2. 180V ADJ PCB - MAIN VR902
3. SCREEN ADJ FLY BACK TRANS T402
4. FOCUS ADJ FLY BACK TRANS T402
5. ABL ADJ PCB - MAIN VR701
6. SUB-BRIGHTNESS ADJ PCB - MAIN VR702
7. FUNCTION ADJ -MENU 2PCB - MAIN SW4
-UP PCB - MAIN SW5
-DOWN PCB - MAIN SW6
-EXIT 1PCB - MAIN SW7
4-3 ADJUSTMENT METHOD
1. 180V, Sub-Brightness & HV voltage adjustment:
A. Chroma-2000 Signal generator or PC equivalent set mode 1, VGA 1024X768 pattern 1.0.
B. Connect a DC Volt meter between D918 cathode and ground, then adjust VR902 to be 180VDC.
C. Connect an accurate,high impedance,HV meter between second anode lead and CRT dag grounding device. Then
adjust VR703 to be 25.0KVDC.
D. Connect a DC Volt meter between TP701(G1) and ground, Brightness set to center and contrast set to max. Then
adjust VR702 to be -10 VDC.
E. Connect a 20kΩresistor in parallel with R403 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 controls. Then press the
Up/Down Key to adjust it's value for the optimum picture.
D. Press 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.
H Model select: for factory only, service engineer can't changed.

9
6500
9300
FH :68.7KHz FV :85.0Hz
70
R
G B
R
G B
CONTRAST H-MOIRE REDUCE
BRIGHTNESS V-MOIRE REDUCE(No use)
H-CENTER R-GAIN
H-SIZE G-GAIN
V-CENTER B-GAIN
V-SIZE R-BIAS
ZOOM G-BIAS
Top corner B-BIAS
Bottom corner 9300 COLOR TEMPERATURE
PINCUSHION 6500 COLOR TEMPERATURE
TRAPEZOID DEGAUSS
PIN-BALANCE OSD EXIT
PARALLELOGRAM RETURN
ROTATION
Vs Linear
Vs Sub V-size
Vc Linear
Vc Sub V-center HS H-SIZE (NO use)
H-Convergence HP Max H-SIZE
V-Convergence
Moire Disable
Exceed Frequency SB Super Brightness Quality
TM Used time BI Burn In
R
G B
R
G B

10
3. White Balance, Luminance adjustment:
A. Bias (Low Luminance) adjustment:
(a) Set mode 5 1024×768 Fh: 68.6KHz full white pattern.
(b) To make the adjustment condition is under the Factory preset window.
Same as step 2-C.
(c) Warm up more than 30 minutes.
(d) Brightness set to center. Contrast set to max. raster pattern, then adjust FBT screen G2 VR to make
Y= 0.18 ±0.03cd/m2.
(e) Make the setting value of B-Bias and R-Bias to 20DAC, keep the value of G-BIAS to
50DAC, then adjust FBT screen G2 VR and the R.B. Bias individual to the color temperature x= 260 ±10, y=
290 ±10,Y=0.18±0.03cd/m2.
(f) Select OSD function to the 9300°K and 6500°K function individually, then press the MENU Key to make the
setting data saved in the memory.
B. Gain (High light) adjustment:
(a) Set mode 5 1024×768 Fh: 68.6KHz 1/3 white area(100mmX100mm Window).
(b) Brightness set to 50DAC and set the contrast to max.
(c) Adjust G-Gain , B-Gain , R-Gain , to make color temperature x=283 ±10, y=297 ±
10,Y=140 ±10cd/m2.
C. 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 B ~ C , with the x=313 ±10, y=329 ±10, Y=140
±10cd/m2.
E. Selet “SB” Function to ON.
F. The adjustment of 9300°K(SBQ) white blance may follow B~C with the x=283±10, y=297±10,Y≥280cd/m2.
G. The adjustment of 6500oK (SBQ) white Balance, May follow B~C with the x=313±10,y=329±10，Y≥260cd/m2.
H. Select “SB” function to OFF and Exit factory preset model.
I. Full white luminance:
(a) Set mode 2 640×480 Fh: 68.6KHz full white pattern.
(b) Image Size : H:310±4mm V:232.5±4mm.
(c) Brightness set to 50 DAC and set the contrast to max.
(d) Adjust VR701 to the luminance at 105±5cd/m2.
4. Focus Adjustment:
A. Set mode5 1024×768 Fh: 68.6KHz 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.
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 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,and composite sync separation Pin41/Pin42 are for the H-SYNC and
V-SYNC 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.

12
On Screen Display Controller
The IC802 on video board 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 (R830, C817,
R833) and filter (R832, C818) 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 IC401 (TDA4856) for this monitor. The
concept is fully DC controllable and can be used in applications with a micro-controller solutions.
The TDA 4856 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 TDA
4887PS [ref Page-28].
Horizontal Oscillator
The oscillator is of the relaxation type and requires a capacitor of 10nF C413 at pin 29. The maximum oscillator
frequency is determined by a resistor R426 form pin 28 to ground. A resistor R425 from pin27 to pin28 defines the
frequency range.
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 C411, R424, C412 is connected to Pin26.
PLL2 Phase Detector
This phase detector is similar to the PLL1 detector and compares the line flyback pulse at pin 1 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 pin30.
X-ray Protection
The X-ray protection input pin2 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:
Pin8 (HDRV) is floating
Pin6 (BDRV) is floating
Pin12, 13 ( VOUT 1, 2) are floating
Pin16 (CLBL) provides a continuous blanking signal.
Vertical Oscillator
The vertical free –running frequency is determined by the resistor R602 at pin23 and capacitor C602 at pin24. Usually the
free-running frequency should be lower than the minimum trigger frequency.
5-3 PFC CIRCUIT
Between rectifier and loading, it is connected a DC-DC switch transformer .Through input current Ii wave following AC
input sinusoid voltage wave, Ii may approach sine wave, and input THD may less than 5%,power factor may improve
more 0.9. IC905 is used for power factor correction . Q910 is DC-DC power switch transistor, and R955、R956 is used as
divider.

13
5-4 TRANSISTOR & DIODE CIRCUIT
LOCATION FUNCTION AL DESCRIPTION
D101 For C103 Discharge
Q101 For LED Indicator Control
D411 Speed up for Q410
D412 Damping Diode
Q405 HDRV Mute Control
Q409 Horizontal Driver
Q410 Horizontal Out Put
Q413 Horizontal Linearity Correction Control
Q415~ Q419 Horizontal S-Correction Control
Q429~ Q433 Horizontal S-Correction Control
D705 Buffer Diode
D701 Rectifier for 250V Supply
D702 Protection Diode for Q701
D703,D704 Rectifier for -200V Supply
Q707 Picture Mute Control AMP
Q705, Q706 Brightness Control CKT
Q701 Vertical Dynamic Focus Control AMP
BD901 Bridge Rectifier for AC Source
D909 Rectifier for Start Power Supply
D907 Clip Diode for Snubber CKT
D906 IC901 VCC Supply
D910 Speed UP for Q901
D911 Synchronous Trigger for Power Supply
D912,D913,D918 Rectifier for 180V Output Voltage Supply
D916,D917,D924 Rectifier for 6.5V,16V,-10V Output Voltage Supply
D914 , D901 Rectifier for 80V Output Voltage Supply
D409, D410 Raster Position Control
D905 Clip Diode for Snuffer Pulse
ZD901 Protection Diode
ZD902 Protection Diode
ZD903 Protection Diode

14
LOCATION FUNCTION AL DESCRIPTION
Q901 MOS FET for Switching Power Control
Q904 Start up CKT for IC901
Q912, Q913 To Turn 6.3V Supply Off when the Off Mode is Required
Q908, Q909 To Turn 16V Supply Off when the Off or Suspend Mode is Required
Q408 MOS FET for B+ Control
Q406, Q407 Push Pull Driver for Q408
D856 ~ D858 DC Restoration for CRT Bias Adjustment
D850 , D852,D854 Protection Diode for Q801, Q802, Q803.
Q850 ~ Q852 DC Restoration for CRT Bias Adjustment

15
6.TROUBLE SHOOTING CHART
6-1 NO RASTER, CRT RELATIVE CIRCUIT PROBLEMS
REFER ITEM S.M.P.S.
CHECK CRT'S HEATER RELATIVE
CIRCUIT
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
REFER ITEM 8-2
CATHODE ABOUT 60V TO 70V
CHECK SCREEN VOLTAGE ABOUT
400V TO 700V
OF CRT ABOUT 25.5 ~ 26.5KV
LESS THAN 300V CHECK FBT
CHECK MAIN PCB POWER SUPPLY
60.5V, 14.5V, 80V
CHECK FAILSAFE CKT IC401
PIN 2 RELATIVE CKT.
Q703, Q706, Q707 RELATIVE CKT.
CHECK MAIN PCB
POWER SUPPLY 180V,16V,80V
CHECK THE HIGE VOLTAGE OF
CRT ABOUT 25±0.3KV OR Q409
DRAIN PIN VOLTAGE WAVE
CHECK SCREEN VOLTAGE
ABOUT 500V TO 800V
CHECK BRIGHTNESS CIRCUIT
Q705,Q706, RELATIVE CKT.
REFER ITEM 6-2 “ABNORMAL
DISPLAY”

16
2.ABNORMAL VIDEO LEVEL ON SCREEN
CHECK 12V RELATIVE
CIRCUIT
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.
OR IC401 PIN 16 OUTPUT
CHECK IC801 PIN 13 ABOUT 4V
PIN 6, 9, 22 ABOUT 12V
CHECK IC801 PIN 15 CLAMP PULSE
PIN 18, 20, 23 ABOUT 4Vpp,
CHECK THE IC105 RELATIVE CIRCUIT
PIN 16 BLANK PULSE
PIN 26, 27, 28 ABOUT 4V OR
CHECK Q801 AND RELATIVE CKT
3. ABNORMAL DDC (PLUG & PLAY)
OK
NG
CHECK IC101 PIN 5 VOLTAGE ABOUT 5V
CHECK SIGNAL CABLE
OR H802 PIN 3, 4 DATA OUTPUT
CHECK Q102 GOOD OR FAIL
HECK THE VOLTAGE OF IC801
PIN7,15,18,21
CHECK IC801 PIN5
CLAMP PULSE PI
11 BLANK PULSE
CHECK THE VIDEO OUTPUT OF
IC801 PIN16,19,22 ABOUT
4Vpp,CONTRAST SET MAX.
IC401 PIN16 OUTPUT
CHECK IC801 PIN24 ABOUT

17
6-2 ABNORMAL DISPLAY
1.NO SIGNAL ON SCREEN
CHECK FBT RELATIVE
CIRCUIT
LESS THAN 400
V
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
OF IC801
CHECK FBT & CRT RELATIVE CIRCUIT
OR REFER ITEM 7-1
VIDEO PCB ABOUT 80V
CHECK THE 80V RELATIVE CIRCUIT
CHECK VIDEO IC801 VCC ABOUT 12V
OF IC801 PIN 18, 20, 23 ABOUT 3Vpp
CHECKTHE VQ802 ~ Q807
CHECK THEOUTPUTVOLTAGE
OF IC801 PIN16,19,22 ABOUT 3Vpp
CHECK THE VOLTAGE OF FBT
SCREEN ABOUT 500V TO 800V
LESS THAN 500V
EXCEED 800V
CHECK THE IC803 PIN1,2,3
OUTPUT RELATIVE CIRCUIT

18
6-3 NO BLANKING
NG
OK
CHECK THE RELATIVE
CIRCUIT OF BLANKING
CHECK THE RELATIVE CIRCUIT
ON MAIN PCB
CHECK G1 RELATIVE CIRCUIT
CHECK IC801 PIN 16 ON VIDEO PCB,
Q705, R718, C707 ON MAIN PCB
OF C433, D410, R635, R636, IC105
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 IC401 PIN 26 ~ 31
CHECK Q402, T401
CHECK T401, T402, Q402, Q403,
OF Q402 ABOUT 40Vpp
OF Q403 ABOUT 1100Vpp AT FH:31KHz
D408, C418, C419, H-DY
CHECK IC401 PIN 10 ABOUT 11.5 VDC
CHECK IC401 PIN 8 WAVE FORM
ABOUT 10Vpp
CHECK IC401 PIN 10 RELATIVE CIRCUIT
CHECK IC801 PIN11 VIDEO PCB,CHECK
G1 RELATIVE CIRCUIT
Q702,Q703,Q704,C711,C712
CHECK THE RELATIVE CIRCUIT OF
D424,R497,ZD404 ON MAIN PCB
CHECK THE COLLECTOR
VOLTAGE OF Q410 ABOUT 900Vpp
AT FH:31KHZ
CHECK THE DRAIN VOLTAGE OF
Q409 ABOUT 40Vpp
CHECK Q409,T401 RELATIVE
CIRCUIT
CHECK Q410,D412,C424,H-DY
Q408,R449

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
Q911, Q912, Q914, Q915 &
IC401 PIN 4, 5, 6, VR 902
ABOUT 60.0V AT FH=31KHz
CRT ABOUT 26KV
2. ABNORMAL HORIZONTAL RASTER CENTER
P403 AND JUMPER
CHECK T903, D926, D927, R964, R968
3. ABNORMAL HORIZONTAL VIDEO CENTER
CHECK IC101 PIN 9, 10, IC401 PIN 18, 19
4. ABNORMAL HORIZONTAL LINEARITY
CHECK L401, Q407, R447, C448
AND IC101 PIN 20, 21, 22, 23
CS SWITCHER IC403, Q410, Q411, Q420
CHECK THE RELATIE CIRCUIT OF
Q409
CHECK THE RELATIVE CIRCUIT OF
SMPS. Q408,IC401 PIN 4、5、6 ,VR902
CHECK FBT B+ VOLTAGE AT Q408
GATE
N
G
OK
CHECK THE HV OF CRT ABOUT
25KV
CHECK T405,D409,D410,R436,P401 AND
JUMPER
CHECK IC101 PIN10,11 IC401 PIN18,19
CHECK T402,Q413,R448,C428 AND IC101 PIN19~23
CS SWITCHER Q429~Q433 Q415~Q419