HP P773Z-2-HPQ Service Manual

SERVICE MANUAL

COLOR MONITOR

HP MX704 Series

41AP773-HP-E49

Ver:A01

Date: Feb-08-04

REV DATE DESCRIPTION APPROVALS
A00 Jan-16-04 NEW VERSION RELEASE
A01 Feb-08-04 Update BOM
A02 Jul-27-05 Update BOM

2

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.

3

TABLE OF CONTENTS

1. SPECIFICATIONS ..................................................................................................... 4-5

2. PRECAUTION AND NOTICES ................................................................................ 6

2-1 SAFETY PRECAUTIONS .............................................................................. 6

2-2 PRODUCT SAFETY NOTICE ....................................................................... 6

2-3 SERVICE NOTES ........................................................................................... 6

2-4 HIGH VOLTAGE WARNING ....................................................................... 7

3. OPERATING INSTRUCTIONS ................................................................................ 8

4. ADJUSTMENT .......................................................................................................... 9

4-1 ADJUSTMENT CONDITIONS AND PRECAUTIONS ............................... 9

4-2 MAIN ADJUSTMENTS ................................................................................. 9

4-3 ADJUSTMENT METHOD ............................................................................. 9-12

5. CIRCUIT DESCRIPTION .......................................................................................... 13

5-1 MICRO CONTROLLER CIRCUIT .............................……………………... 13

5-2 DEFLECTION CIRCUIT .............................………………………………... 13

5-3 TRANSISTOR & DIODE CIRCUIT .............................……………………. 14

6. TROUBLE SHOOTING CHART .............................................................................. 15

6-1 NO RASTER, CRT RELATIVE CIRCUIT PROBLEMS ............................. 15-16

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 ....................................................................................................... 23-43

9. BLOCK DIAGRAM .....................................................................………………….. 44-47

10. IC BLOCK DIAGRAMS............................................................................................ 46-51

11. PCB LAYOUT ............................................................................................................ 52-53

12. SCHEMATIC DIAGRAM ......................................................................................... 54-57

4

1. SPECIFICATIONS FOR HP MX704 SERIES COLOR MONITOR

1. CRT : 43.2CM(17") 90 Deflection, 29mm Neck, 0.27mm Dot Pitch, Pure Flat, Non-Glare Screen

2. Viewable image Size: 40.6CM (16") diagonal

3. Display Color: Unlimited Colors

4. External Controls:
Power On/Off, Power led, Function knob( Contrast, Brightness, H-Center, H-Size, V-Center, V-Size,
Rotation, Pincushion, Trapezoid, Pin-Balance, Parallelogram, Color Temperature, Degaussing, Recall, Exit,

5. Input Video Signal

Mode

1 2 3 4 5 6 7 8 9
Horizontal Freq. (KHz) 31.47 31.47 37.500 43.27 46.87 53.674 60.023 68.677 63.981
Dot Clock (MHz) 28.30 25.175 31.500 36.00 49.50 56.25 78.75 94.50 108.00
Horizontal Lines 720 640 640 640 800 800 1024 1024 1280
Vertical Lines 400 480 480 480 600 600 768 768 1024
H. Sync Polarity NEG NEG NEG NEG POS POS POS POS POS
H. Period (µs) 31.921 31.778 26.667 23.111 21.333 18.631 16.660 14.561 15.630
H. Sync Width (µs) 3.814 3.813 2.032 1.556 1.616 1.138 1.219 1.016 1.037
H. Back Porch (µs) 1.907 1.589 3.810 2.222 3.232 2.702 2.235 2.201 2.296
H. Active (µs) 25.424 25.422 20.317 17.778 16.162 14.222 13.328 10.836 11.852
H. Front Porch (µs) 0.911 0.318 0.508 1.556 0.323 0.569 0.203 0.508 0.444
H. Blanking (µs) 5.861 5.720 6.349 5.333 5.172 4.409 3.657 3.725 3.778
Vertical Freq. (Hz) 69.616 59.940 75.000 85.008 75.00 85.061 75.029 84.997 60.020
V. Sync Polarity POS NEG NEG NEG POS POS POS POS POS
V. Period (ms) 14.364 16.683 13.333 11.764 13.333 11.756 13.003 11.765 16.661
V. Sync Width (ms) 0.064 0.064 0.080 0.069 0.064 0.056 0.050 0.044 0.047
V. Back Porch (ms) 1.149 0.794 0.427 0.578 0.448 0.503 0.466 0.524 0.596
V. Active (ms) 12.768 15.253 12.800 11.093 12.800 11.179 12.795 11.183 16.005
V. Front Porch (ms) 0.000 0.064 0.027 0.023 0.021 0.019 0.01 7 0.015 0.016
V. Blanking (ms) 1.149 0.922 0.533 0.670 0.533 0.578 0.533 0.582 0.656

6. Scanning Frequencies
Horizontal:

30KHz ~ 70KHz

Vertical:

50 Hz ~ 140 Hz

7. Factory Preset Timings:9

User Timings: 8

8. Video Bandwidth: 110 MHz

9. Power Source:

Switching Mode Power Supply
AC 90 ~265V, 50/60Hz Universal Type

10. Operating Temperature: 10°C to 35°C Ambient

5

11. Humidity: 20% to 80% Relative, Non-Cond ensing

12. External Connection:

15 Pin D-type Connector
AC Power Cord

13. Regulations:UL, CSA, FDA, FCC, TÜV/GS, CE, MPR-II,TCO,CCC

14. Key FOS spec.

NO Measurement Item Conditions Spec

1

Image size

B-50 % C→MAX

W=312±4 mm

H=234 ±4 mm

2

Image centering

B-50 % C→MAX HOR.|a-b|≦4.0mm

VER.|c-d|≦4.0mm

3

Geometry Distortion

B-50 % C→MAX

<2.0mm

4

Tilt

B-50 % C→MAX HOR≦1.0 mm

5

Raster Luminance

B-MAX C→MAX 0.2 ～ 2.0 FL

B

lack pattern

6

Full White

B-50 % C→MAX ≧30 FL

7

ABL (30% block) luminance

B-50 % C→MAX ≧45 FL

8 Size regulation

B-50 % C→MAX

<1mm (each side)

9

Color Temperature / 9300K

B-50 % C→MAX

x/y:0.283/0.298± 0.015

Color Temperature / 6500K

B-50 % C→MAX

x/y:0.313/0.329± 0.015

Color Temperature / 5500K

B-50 % C→MAX

x/y:0.333/0.348± 0.015

10

Purity

B-50 % C→MAX

x, y <0.015

11 Color Tracking

B-50 % C→MAX

x/y: ± 0.015

Default → 5 FL

12

Brightness Uniformity

B-50 % C→20 FL ≧75 %

13 Linearity

B-50 % C→20 FL (max-min) /(Max+Min) ×100≦5 ﹪

12x9 X-hatch Adjacent < 4%

14

Power consumption

N

ormal <100W (LED Green)

Active off < 4W (LED Amber)

Switch off

<1W (LED OFF)

15

Misconvergence

B-50% C→MAX Zoon A (Center )≦0.25mm

Zone B (Circle )≦0.35 mm

VGA MODE Zone A≦0.30 mm Zone A≦0.40

6

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 no t be attempted by anyone who is not thoroughly familiar
with precautions necessary when working on high volt age 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, VR701 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 VR903 to make sure the voltage about 13.8V,please adjust the relative VR to make sure the B+
voltage about 58.0V for CPT CRT and 57.0V for LPD CRT, 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.

7

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

24.8KV ± 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 h igh 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.

8

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. Three­wire 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. SYNC. GND

3. BLUE 11. NC

4. NC 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 color display requires service, it must be returned with the power cord.

1

6

11 15

5

10

9

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 TP901ADJ PCB - MAIN VR903
2 B + ADJ PCB - MAIN VR902
3 SCREEN ADJ FLY BACK TRANS T402
4 FOCUS ADJ FLY BACK TRANS T402
5 ABL ADJ PCB - MAIN VR701

-MENU PCB - MAIN SW101

- DOWN (-) PCB - MAIN SW102

6 FUNCTION ADJ

- UP (+) PCB - MAIN SW103

4-3 ADJUSTMENT METHOD

1. TP901, B + & HV voltage adjustment:

A. Chroma-2000 Signal generator or PC equivalent set mode 1, VGA 640X480 patt ern 1.0 .
B. Connect a DC Volt meter between TP901 and ground, then adjust VR903 to be 13.8VDC for CPT CRT or

LPD CRT.

C. Connect a DC Volt meter between TP902 and ground, then adjust VR902 to be 62.0 VDC for CPT CRT or

LPD CRT.

2. Factory preset Timings Adjustment:

A. Press MENU Key to show OSD window press Up or Down Key to switch the functio nal controls.
B. Press the Up Key to select the "EXIT" 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.

10

(The OSD menu for factory preset FOR WT CPU)

H-SIZE

H-MOIRE REDUCE

H-CENTER

MOIRE DISABLE

V-SIZE

HE

NO USE

V-CENTER

VE

NO USE

PINCUSHION

NO USE

PARALLELOGRAM

V-LINEARITY

PIN-BALANCE

V-LINEARITY

TRAPEZOID

TOP CORNER

ROTATION

BOT CORNER

SH

NO USE

AB

NO USE

CONTRAST

HM

MAX-HSIZE MODIFY

BRIGHTNESS

VM

MAX-VSIZE MODIFY

R-BIAS

KM

MAX-TRAPEZOID MODIFY

G-BIAS

BI

BI SELECT FUNCTION

R-BIAS

DEGAUSS

R-GAIN

OSD EXIT

G-GAIN

RETURN

B-GAIN

Tm

BURN IN TIME

11

9300 COLOR TEMPERATURE

USER OSD HORIZONTAL LOCATION

ADJUST

6500 COLOR TEMPERATURE

USER OSD VERTICAL LOCATION

ADJUST

5500 COLOR TEMPERATURE

FV

F

ACTORY OSD VERTICAL LOCATION

ADJUST

V-MOIRE REDUCE

Max H-Frequency select

D. To switches the input signal to th e other Timing Mode. Please follow step A ~ C to get the optimum

picture.(H/V-size:312*234mm)

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, 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 (Raster) adjustment:

(a) Set mode8 1024×768 @85Hz full white pattern(100% white field).
(b) To make the adjustment condition is under the Factory preset OSD menu.

Same as step 2-B.

(c) Warm up more than 20 minutes.
(d) Put the probe in the middle of screen, Brightness

set to maximum. Contrast set to max.

change to Raster pattern(No video)1024×768 @85Hz, set G-Bias

40,then adjust B-Bias

, R-Bias and FBT scr een VR, to make the color temperature x= 265 ±10, y= 290 ±

10, Y=0.6±0.02FL

(e) Press up or down key to select cursor on 9300 icon and than press menu key for saved the bias data to

EEPROM.

B. 9300 and 6500 5500 color temperature window pattern(20% white field) adjustment:

(a) Set mode 1024×768 @ 85Hz Rast er patte r n.
(b) adjust Brightness , to make raster Luminance is 0.06 FL.
(c) Change mode to 1024×768 @ 85Hz window pattern(20% white field).put the probe in the middle of

screen ,Adjust G-Gain

, B-Gain , R-Gain , to make color temperature
x=283±10, y=297 ± 10, Y= 48±0.6FL.then save to 9300.(u se up/down key select cursor on 9300
icon and than press menu key)

(d) Adjust G-Gain

, B-Gain , R-Gain , to make color temperature x=313±10,

y=329± 10, Y= 48±0.6FL.then save to 6500.

(e) Adjust G-Gain

, B-Gain , R-Gain , to make color temperature x=333±10,

y=346± 10, Y= 48±0.6FL.then save to 5500.

C.Full white luminance(100% white field) for 9300:

(a) Set mode 1024×768 @ 85Hz full white field
(b) Adjust VR701 to the luminance at 33 ± 0.3FL.

D.Cut off adjustment:

(a) Set mode 1024×768 @85Hz Raster pattern.
(b) Adjust Brightness , to make Y= 0.06 FL.then return from factory OSD mode to user OSD mode.

4. Focus Adjustment:
A. Set mode 1024×768 @85Hz with crosshatch pattern.
B. Then adjust focus VR1 to a fine vertical line.
C. Adjust focus VR2 to a fine horizontal line.
D. Repeat step B & C. and change to full text pattern double check focus uniformity.

12

5. Purity Adjustment
A. Be sure that the display is not being exposed to an y 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

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.

13

5. CIRCUIT DESCRIPTION

5-1 MICRO CONTROLLER CIRCUIT

MICRO Controller

The IC101 contains a 6502/8051 8-bit CPU core, 512 bytes of RAM, 16K bytes of ROM,14 chann el 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 V­SYNC 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 72Hz V-SYNC free run signal. The Pin33
will output a 48KHz H-SYNC free run signal. for the monitor testing use.

5-2 DEFLECTION CIRCUIT

The deflection circuit is achieved by a high performance and efficient solution IC 401 (STV6888) for this
monitor. The concept is fully DC controllable and can be used in applications with a micro-controller solutions.
The STV6888 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 TDA9302A.

Horizontal Oscillator

The oscillator is of the relaxation type and requires a capacitor of C409 at pin6. The free running frequency is
determined by a resistor R412 from pin8 to groun d.

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 is connected to Pin9.

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 pin5.

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

Vertical Oscillator

The vertical free –running frequency is determined by the capacitance C613 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

BD901 Bridge Rectifier for AC Source
D910 Clamp Diode for snub 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
IC901,Q901 Power IC for Switching Power Control. (Build-in MOS FET)
Q907, Q908 Use for Power Saving to Cut-off 6.3V Supply Voltage
Q909, Q910 Use for Power Saving to Cut-off 14V Supply Voltage
Q912, Q920 Push-Pull Topology to Drive Q911
Q913 Degaussing Switcher Transistor
Q906 5V Regulator Transistor
Q402 HOR. Driver Transistor
Q440 Horizontal s correction control MOSFET(Four in one)
Q404, Q405 As Differential Amp. to Drive Q406
Q406 Transistor for H-Size Control
Q705 Brightness Control CKT
Q742 V-Dynamic focus CKT

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 MAIN PCB POWER
SUPPLY57.0V,13.6V,80V

CHECK THE HIGE VOLTAGE OF
CRT ABOUT 23~25KV

CHECK BRIGHTNESS CIRCUIT
Q705 RELATIVE CKT.

16

2.ABNORMAL VIDEO LEVEL ON SCREEN

3. ABNORMAL DDC (PLUG & PLAY)