Memorex MT2025D - 20" CRT TV Service Manual

CAUTION READ

THIS MANUAL CAREFULLY TO DIAGNOSE

TROUBLE CORRECTLY BEFORE OFFERING

SERVICE .

SERVICE MANUAL

Colour Television

Haier model:

21F7A

Customer model:

MT2025D

l

FEATURES

l DVD-TV 21 ” COMBO l AUTO TUNE/181 CHANNES l DVD/VCD/SVCD/CD/CD-R/CD-RW/JPEG/MP3 COMPATIBLE l FORMATO DE VIDEO 4:3PS 、 4:3LB l l l l

DOLBY AC-3 DECODE

PANATAL LOCK

ATSC TUNER

AC/DC

PDF 文件使用 "pdfFactory Pro" 试用版本创建 www.fineprint.com.cn

.

CONTENTS

1. Safety precautions …………………………………………………………… ..

…………… 3

2. TV block diagram …………………………………………………………………… ..

…… .4

3. Replacement of memory IC ………………………………………………………… .

…… 5

4. Service adjustment …………………………………………………………… ..

………… ...5

5. ICs functional description ………………………………………………………………… 8

6. Test point waveform ……………………………………………………………………… 10

7. All ICs voltages …………………………… ..

……………………………………………… .10

8. Purity / convergence adjustment ……………………………………………………… 11

9. DVD maintenance ………………………………………………………………………… 13

2


.

1. SAFETY

1. The design of this product contains special hardware, many circuits and components especially for safety purposes. For continued protection, no changes should be made to the original design unless authorized in writing by the manufacturer. Replacement parts must be identical to those used in the original circuits. Service should be performed by qualified personnel only.

2. Alterations of the design or circuitry of the products should not be made. Any design alterations or additions will void the manufacturer ’ s warranty and will further relieve the manufacturer of responsibility for personal injury or property damage resulting therefrom.

3. Many electrical and mechanical parts in the products have special safety-related characteristics. These characteristics are often not evident from visual inspection nor can the protection afforded by them necessarily be obtained by using replacement components rated for higher voltage, wattage, etc. Replacement parts which have these special safety characteristics are identified in the parts list of Service manual. Electrical components having such features are identified by shading on the schematics and by ( ！ ) on the parts list in Service manual. The use of a substitute replacement which does not have the same safety characteristics as the recommended replacement part shown in the parts list of Service manual may cause shock, fire, or other hazards

4. Don ’ t short between the LIVE side ground and

ISOLATED (NEUTRAL) side ground or EARTH side ground when repairing . Some model ’ s power circuit is partly different in the GND. The difference of the GND is shown by the LIVE: ( ) side GND, ISOLATED

(NEUTRAL): ( ) side GND and EARTH: ( ) side GND.

Don ’ t short between the LIVE side GND and ISOLATED

(NEUTRAL) side GND or EARTH side GND and never measure with a measuring apparatus (oscilloscope etc.) the

LIVE side GND and ISOLATED (NEUTRAL) side GND or

EARTH side GND at the same time. If above note will not be kept, a fuse or any parts will be broken.

5. If any repair has been made to the chassis, it is recommended that the B1 setting should be checked or adjusted (See ADJUSTMENT OF B1 POWER SUPPLY).

6. The high voltage applied to the picture tube must conform to that specified in Service manual. Excessive high voltage can cause an increase in X-Ray emission, arcing and possible component damage, therefore operation under excessive high voltage conditions should be kept to a minimum, or should be prevented. If severe arcing occurs, remove the AC power immediately and determine the cause by visual inspection (incorrect installation, cracked or melted high voltage harness, poor soldering, etc.). To maintain the proper minimum level of soft X-Ray emission, components in the high voltage circuitry including the picture tube must be the exact replacements or alternatives approved by the manufacturer of the complete product.

7. Do not check high voltage by drawing an arc. Use a high voltage meter or a high voltage probe with a VTVM.

Discharge the picture tube before attempting meter connection, by connecting a clip lead to the ground frame and connecting the other end of the lead through a 10k Ω 2W resistor to the anode button.

8. When service is required, observe the original lead dress.

Extra precaution should be given to assure correct lead dress in the high voltage circuit area. Where a short circuit has occurred, those components that indicate evidence of overheating should be replaced. Always use the manufacturer ’ s replacement components.

PRECAUTIONS

9. Isolation Check

(Safety for Electrical Shock Hazard)

After re-assembling the product, always perform an isolation check on the exposed metal parts of the cabinet (antenna terminals, video/audio input and output terminals, Control knobs, metal cabinet, screw heads, earphone jack, control shafts, etc.) to be sure the product is safe to operate without danger of electrical shock.

10. The surface of the TV screen is coated with a thin film which can easily be damaged. Be very careful with it when handle the TV.

Should the TV screen become soiled, wipe it with a soft dry cloth. Never rub it forcefully. Never use any cleaner or detergent on it.

(1) Dielectric Strength Test

The isolation between the AC primary circuit and all metal parts exposed to the user, particularly any exposed metal part having a return path to the chassis should withstand a voltage of 3000V AC (r.m.s.) for a period of one second.

( … Withstand a voltage of 1100V AC (r.m.s.) to an appliance rated up to 120V, and 3000V AC (r.m.s.) to an appliance rated 200V or more, for a period of one second.)

This method of test requires test equipment not generally found in the service trade.

(2) Leakage Current Check

Plug the AC line cord directly into the AC outlet (do not use line isolation transformers during this check). Using a

“ Leakage Current Tester ” , measure the leakage current from each exposed metal part of the cabinet, particularly any exposed metal part having a return path to the chassis, to a known good earth ground (water pipe, etc.). Any leakage current must not exceed 0.5mA AC (r.m.s.).

However, in tropical area, this must not exceed 0.2mA AC

(r.m.s.).

● Alternate Check Method

Plug the AC line cord directly into the AC outlet ( do not use a line isolation transformer during this check.). Use an AC voltmeter having 1000 ohms per volt or more sensitivity in the following manner. Connect a 1500 Ω 10W resistor paralleled by a 0.15

μ F AC-type capacitor between an exposed metal part and a known good earth ground (water pipe, etc.). Measure the AC voltage across the resistor with the AC voltmeter. Move the resistor connection to each exposed metal part, particularly any exposed metal part having a return path to the chassis, and measure the AC voltage across the resistor. Now, reverse the plug in the AC outlet and repeat each measurement. Any voltage measured must not exceed 0.75V AC (r.m.s.). This corresponds to

0.5mA AC (r.m.s.).

However, in tropical area, this must not exceed 0.3V AC

(r.m.s.).

This corresponds to 0.2mA AC (r.m.s.)

3


.

2. Block diagram R2J10165GC series with stereo intercarrier sound demodulator


4

3. REPLACEMENT OF MEMORY IC

1. MEMORY IC.

This TV uses memory IC. In the memory IC are memorized data for correctly operating the video and deflection circuits.

2. PROCEDURE FOR REPLACING MEMORY IC

(1) Power off

Switch the power off and unplug the power cord from AC outlet.

(2) Replace IC

Be sure to use memory IC written with the initial data values.

(3) Power On

Plug the power cord into the AC outlet and switch the power on.

(4) Check and set SYSTEM default value:

1) Press “ MENU ” à “ 8 ” à ” 8 ” à ” 9 ” à ” 3 ” buttons in sequence to enter into factory status.

2) If the memory IC haven ’ t been written with the initial data, press [Program+] / [Program-] to select item INIT and press [VOLUME+] / [VOLUME-] to start initialize memory IC.

3) Check the setting value of the SYSTEM default value of Table below. If the value is different, select items by [Program+] / [Program-] keys and set value by [VOLUME+] / [VOLUME-] keys.

4) Press “ EXIT ” button to return to the normal screen.

4. SERVICE ADJUSTMENT

Specific operation: use remote controller

Press

“

MENU

” à “

8

” à ”

8

” à ”

9

” à ”

3

”

buttons in sequence to enter into factory mode.Press

“

MENU

”

to enter into next factory menu.

Press [Program+] / [Program-] to select items and press [VOLUME+] / [VOLUME-] key, to make data adjustment of corresponding factory menus.

Press

“

EXIT

”

key to exit factory mode.

Focus adjustment

1. Receive a crosshatch signal.

2. While watching the screen, adjust the FOCUS VR on the FBT to make the vertical and horizontal lines as fine and sharp as possible.

Geometrical adjustment

Receive NTSC standard complete pattern signal.

Adjustment steps ： a) Adjust V SC , S emendation b) Adjust V SIZE , to get 92% of vertical picture contents would be displayed on CRT. c) Adjust V POS , the centre horizontal line corresponds to CRT vertical centre. d) Adjust V LIN , to the linearity of P card field is in proper condition. e) Adjust H PHASE , to get the picture horizontal centre correspond to CRT horizontal centre.

Receive NTSC signal and repeat above adjustment.

0


AGC Adjustment

Receive 60dB

μ

(1mV) VH colour bar pattern signal.

Select RF AGC item.

Adjust value, to noise reduce gradually and just disappeared point.

CRT cut off and white balance adjustment a) CRT cut off adjustment

1. Select item VG2B, then adjust value to 32.

2. PRESS

“

MENU

”

key to page 2, when the screen shows

”

VK

”

adjust the SCREEN control on Fly back transformer to make the screen show alternating flashing characters to darkle.

b) White balance adjustment

1. Receive a Black and White pattern.

Maintenance Service and Trouble shooting

2. Adjust RC , GC, BC,RD,BD items to get colour temperature 9300K

±

3 JND.

A3. Error Detection Process

1.

Normal

No light and sound

Check to see if

Fuse is normal

Abnormal

Check D901~D904,

C914, IC9601, Q901

Check to see if the collector voltage of

D909 is 13.5V

Normal

Normal

Check to see if , ZD201 8v, is normal

Normal

Abnormal

Check the control voltage of Q207 or

CPU power pin

Abnormal

Check to see 110V 、 180V etc. voltage is normal

Test to see all terminal

Normal

Resistance of load

Check switch power unit

Normal

Abnormal

Abnormal

Check to see if rectifying tube is normal

Abnormal orN204

Check IC602 ,ect

Check the

Loader

Change rectifying diode

1



2

No raster

Whether G2 voltage is normal

Normal

Test filament voltage

Normal

Check the voltage of all pins of SK501

Abnormal

Heater Resistor open

Test the base voltage of Q402

Normal

Check to see if be voltage of Q402 is existed?

Abnormal

Abnormal

Check the circuit from pin15 of IC201 to Q402

Abnormal

YES

Normal

Video amplifying board is abnorma l

Inspect the circuit from pin51 、 52 、

53 of IC201 to video amplifying

NO

Check the voltage of Q402 collector is normal

Higher Lower

InspectT402 、 R427 etc . board

T401, D402 or

C419,C420 are broken

Q402 is not well welded or open

Normal

Check to see if +8V voltage is normal at

PIN 10 or 14 of IC201

Abnormal

Change wrong component

Check X201 、 IC201 and peripheral circuit of IC201 or check

Check +8V ,+5V power

2



3

Yes

Check to see if the voltage of pin 11 and pin12 of IC201 is normal

Horizontal bright line

Make R429 open. Multimeter is at range R Χ 1K. Red probe connects to ground. Touch No.5 of IC401 with black probe. Bright line flashes for a moment

No

Check to see if voltage of pin2 at

IC401 is normal

4.

Yes

Change IC201 and repair circuit

Normal

No

Inspect IC201 and peripheral components of

IC201

Yes

Check to see if the deflection yorks are connected, C404 is open or weldless. Inspect peripheral component of IC401 and IC401 itself

No sound and picture

No

Inspect +28V power supply

Not exist

Check to see if RAGC is at 00 mode

Yes

Enter D-MODE with customer remote controller.

Make RAGC tuned to 25 or so. Noise on picture just disappears.

Snowy noise exist

No

Inspect SAW101

IC201and PIF

、 part

Check to see if voltage output available at tuner

Yes

Antenna or tuner is abnormal

Exist

No

Inspect the circuit from

CPU to tuner

3



5

6.

Picture exists but no sound

Make C713/C714 open. Multimeter is at band R

Χ

1K. Red probe connect to ground. Touch No.6 OR No.8 of IC701 with

No noise

Power amplifier is abnormal.

Inspect IC701 and peripheral components of IC701

Yes

Inspect IC201 and peripheral component of IC201

Have noise

Make C713 OR C714 collector open. Touch No.6 OR No.8 of

Q702 with black probe to see if

Yes

Inspect C713 、 C714

Lack of red

Yes

Change V501 or weld V501 again

Check to see if V501 is open or not well welded

No

Check to see if voltages of SK501 are normal

No

No

Check to see if

+16V exists

No

Inspect +16V power supply

Yes

Inspect the circuit from

No.51 of IC201 to

No.3 of SK501

4


Adjustable Items

P1 ：

Items

H PHASE 0 ~ 31

V SIZE 0 ~ 63

V POS 0 ~ 7

V LIN 0 ~ 63

V SC 0 ~ 63

PARABOLA 0 ~ 63

注：

Preset Remark Description

14

20

2

29

32

32

TRAPEXIUM 0 ~ 63 32

H SIZE 0 ~ 63 32

CORNER 0 ~ 63 40

★

★

★

★

★

★

★

★

★

Horizontal shift

Vertical amplitude

Vertical shift

Vertical slop

S emendation

S-correction

Echclon distortion correction

Horizontal amplitude

TOP Vertical distortion correction

P2 ：

Items

RC 0 ~ 255

GC 0 ~ 255

BC 0 ~255


120

★ White point R

120

120

★

★

White point G

White point B

RD 0 ~ 127

BD 0 ~ 127

SB 0 ~ 127

VK 0 ~ 1

70

75

47

0

WB BRI 0 ~ 127 47

★

★

★

★

★

Black level offset R

Black level offset B

Aassistant brightness adjust

Horizontal line choice

Horizontal line

[field surge stop choice]

brightness

P3

：

Items

RB YUV -128~ 128


0

◆

IN YUV

，

Black level offset R

GB YUV -128~ 128 0 ◆

IN YUV

，

Black level offset G

BB YUV -128~ 128 0 ◆

IN YUV

，

Black level offset B

RD YUV -128~ 128 0 ◆

IN YUV

，

White point R

BD YUV -128~ 128 0 ◆

IN YUV

，

White point B

CR PEDDOT 0~15

CB PEDDOT 0~15

CRCB PED ON 0~1

CRCB GAIN UP 0~1

8

8

1

0

◆

◆

◆

◆

CR benchmark voltage adjust

CB benchmark voltage adjust

YUV benchmark voltage switch

YUV benchmark voltage plus

P4

：

Items

VIF VCO OK

S TRAP OK

RF AGC 0 ~ 127


OK

◆

Picture IF adjust

OK ◆ Sound frequency adjust

35 ◆

AGC adjust

VIDEO LVL 0 ~ 7 7

◆

Video demodulation output voltage control

P5

：

Items

OSD HP 0 ~ 63

OSD VP 0 ~ 31

H TONE 0 ~ 1

A OSD 0 ~ 1

OSD L 0 ~ 1

TITLE 0 ~ 127

MENU 0 ~ 127

MENU HL 0 ~ 127


35

◆

OSD Horizontal vision position adjust

21 ◆ OSD Vertical vision position adjust

0 ◆

Translucence ON-OFF

0

0

57

79

57

◆

◆

◆

◆

◆

A/D OSDchoice; 0 = D OSD; 1 = A OSD;

D OSD output voltage choice; 0 = 70%; 1 = 90%

OSD title color choice

OSD color choice

OSD pitch on color choice

5


P6

：

Items

ENG 0 ~ 1

FRE 0 ~ 1

1

1

SPA 0 ~ 1

POR 0 ~ 1

DVD MD 0 ~ 3

1

0

1

DVD OFF T 0~ 127 0

2DVD BLK T 0~ 255 70


№

№

№

№

№

№

№

English OSD

；

ON = Y

French OSD ON = Y

Spanish OSD ON = Y

Portugal OSD ON = Y

DVD signal format

，

；

；

；

；

OFF = N

OFF = N

OFF = N

OFF = N

0:CVBS

Power off DVD off delay time

Tv to DVD black screen time

；

1:YC

；

2:YUV

；

3

： hold

P7 ：

Items Preset Remark Description

ON DLY T 0 ~ 15

AVS MUTE TIM 0 ~ 255

LOGO COLOR 0 ~ 7

LOGO 0 ~ 1

INT AUDIO 0 ~ 1

BTSC 0~1

FAC SW 0 ~ 1

6

30

1

0

1

0

0

№

№

№

№

№

◆

№

POW MD 0~3 0 №

C_10164/5 070119 №

Power on black screen time

Label color choice

MTS ON-OFF

Foctory adjust hotkey

Power 0=standby

，

ATV software edition

；

；

0-15s

Change channal black screen time;10ms

Label choice ON-OFF ON =Y; OFF =N

Inside volume cortrol choice

；

ON = Y

1=power ON

；

OFF = OUT PWM

OFF = N

，

2=memory

，

3=else

P8

：

Items

AUTO/N/PM/PN 0 ~ 1

AUTO/N/N4/P 0 ~ 1

PAL 0 ~ 1

NTSC 0 ~ 1

N443 0 ~ 1

P358 0 ~ 1

PAL M 0 ~ 1

PAL N 0 ~ 1


1

0

0

1

1

0

0

0

◆

◆

◆

◆

◆

◆

◆

◆

AUTO/N/PM/PN function choice

AUTO/N/PM/PN function choice

PAL ；

NTSC

0 = N

；

3.58PAL

； 1 = Y

ON = Y

NTSC4.43

；

；

0 = N

；

；

OFF = N

ON = Y

；

OFF = N

1 = Y

PAL – M

；

ON = Y

；

OFF =N

PAL-N

；

ON = Y

；

OFF = N

P9 ：

Items

AV2 0 ~ 1

YUV 0 ~1

DVD 0 ~ 1


1

0

0

★

★

★

AV2

；

1= Y

；

0 = N

YUV

；

1 = Y

；

0 = N

DVD

；

1= Y

；

0 = N

P10 ：

Items

Y DL 0 ~ 7


5 № Brightness signal delay time adjust

Y LPF 0 ~ 1 0 № Brightness signal output low pass choice switch;0 = flat out; 1 = low out(fc = 700kHz)

BLK STE OFF 0 ~ 1

GAMMA 0 ~ 3

ABCL 0 ~ 1

0

0

0

№

№

№

Black voltage extend function switch; 0 = ON; 1=OFF

GAMMA adjust control; 0 = OFF; 1~3 = ON(3 mode)

AUTO brightness and contrast limit; 0 = AUTO contrast limit; 1 = AUTO brightness and contrast limit

ABCL GAIN 0 ~ 1 0 № AUTO brightness and contrast limit plus switch; 0 = low; 1

= high

6


U DL 0 ~ 3

V DL 0 ~ 3

LCNR 0 ~ 63

3

0

32

№

№

№

U signal delay adjust

V signal delay adjust

Down pillow shape distortion

.

P11 ：

Items Preset Remark Description

C TRAP 0 ~ 3 2 № Colour trap wave adjust

H VCO 0 ~ 7

SIF BFP 0 ~ 3

SIF45 G DN 0 ~ 1

3

0

0

№

№

№

Row frequency adjust

SIFstrap pass width choice

4.5Mhz sound plus attenuation switch

；

0 = normal

；

1 = attenuation 。

STRAP OFF 0 ~ 1

AFC1 UP 1 0 ~ 1

AFC1 UP 2 0 ~ 1

AFC2 UP 0 ~ 1

0

1

1

AFC2 DOWN 0 ~ 1 0

1

№

№

№

№

№

Sound trap wave switch

Level AFC1 plus adjust

Level AFC1 plus adjus



5. ICs functional description

1. IC201 R2J10165GC

SYMBOL PIN

SP00/14bPWM

SP01/PWM

SP02/PWM

SP03/PWM

TEST0

P04/AD2

P05/AD1

P06/TIM31

AFT(AD0)

DEF VCC(8.0V)

V RAMP(+)

VRAMP CAP

AFC 1 FIL

DEF VCC(5.0V)

H OUT

FBP IN

DEF GND

VRAMP AGC

Cb IN YcbCr

Cr IN YcbCr

C-APC

XTAL

CHROMA GND

Y SW OUT

TEST/EW OUT

MCU 5.7 VDD OUT

PAL ID FIL

8.7V REG OUT

EXT AU(L)IN/EXT AU2

IN

EXT2 IN/C IN YC

CHROMA VCC(5.0)

EXT 1 IN/YIN YC/YIN Y

CbCr

5.7V REG OUT

VIF VIDEO OUT

VIF GND

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

SP00/14bPWM

SP01/PWM

SP02/PWM

SP03/PWM

TEST0

P04/AD2

P05/AD1

P06/TIM31

SIF auto phase control

8V POWER

V RAMP(+)

VRAMP CAP

SIF auto phase control filter

5V POWER

Horizontal SIGNAL OUT

FBP IN

GND

VRAMP AGC

Cb IN YcbCr

Cr IN YcbCr

C-APC

XTAL

CHROMA GND

Y SW OUT

TEST/EW OUT

MCU 5.7 VDD OUT

PAL ID FIL

8.7V POWER OUT

EXT AU(L)IN/EXT AU2 IN

EXT2 IN/C IN YC

CHROMA VCC(5.0)

EXT 1 IN/YIN YC/YIN Y CbCr

5.7V POWER OUT

VIF VIDEO OUT

GND

DESCRIPTION

7


MNITOR-OUT

MCU RESET

P20

P21

P22

HLF

VHOLD

CVIN

P26/AD6

AD6/P27

P35/TIM21

CNVSS

TEST1 Note1

TEST2 Note2

VSS

FILT

VDD

P36

P17/INT3/AD4

P16/INT2/AD3

P15/INT1

P10

P11/SCL1

P12/SCL2

P13/SDA1

P14/SDA2

VIF APC

RF AGC

VIF IN2

VIF IN1

VIF AGC

VIF VCC F/B

VIF VCC(5.0V)

EXT AU R IN/EXT AU1

IN

AU BYPASS

SIF MIX F/B

AU ATT （ R ） OUT/ATT

OUT

DIRECT OUT

AU ATT （ L ） OUT/ATT

OUT

ACL/ABCL

HI VCC （ 8.0

）

R OUT

G OUT

B OUT

VREG VCC （ 8.7V

）

2. IC602 24C16

PIN

4

5

6

1

2

3

7

8

49

50

51

52

53

54

71

72

73

74

75

76

77

78

79

80

62

63

64

65

66

67

68

69

70

55

56

57

58

59

60

61

36

37

38

39

40

41

42

43

44

45

46

47

48

VIF APC

RF AGC

VIF IN2

VIF IN1

VIF AGC

VIF VCC F/B

5.0V POWER

EXT AU （ R ） IN/EXT AU1 IN

AU BYPASS

SIF MIX F/B

AU ATT （ R ） OUT/ATT OUT

DIRECT OUT

AU ATT （ L ） OUT/ATT OUT

ACL/ABCL

HI VCC （ 8.0

）

R OUT

G OUT

B OUT

VREG VCC （ 8.7V

）

MNITOR-OUT

MCU RESET

P20

P21

P22

HLF

VHOLD

CVIN

P26/AD6

AD6/P27

P35/TIM21

CNVSS

TEST1 Note1

TEST2 Note2

VSS

FILT

VDD

P36

P17/INT3/AD4

P16/INT2/AD3

P15/INT1

I

I

I

I

PIN 10

2

2

C-bus clock line 1

2

C-bus clock line 2

2

C-bus data line 1

C-bus data line 2

Function

GND

GND

Upper resistance

GND

SDA data wire

SCL clock wire

GND

+5V Power

8


3. IC701: Sound power amplify (TFA9800J)

Symbol PIN Function Symbol

-INV1 1 Non-inverting input 1 Vp

SGND 2 Signal ground M/SS

PIN Function

7

8

Supply voltage

Mute/standby input switch

SVRR

Out 1

PGND

OUT2

3

4

5

6

Supply voltage ripple rejection output

Output 1

Power ground

Output 2

4. IC401: Vertical output (STV9302A()

Symbol PIN Function

-INV2

INPUT 1

SUPPLY VOLTAGE 2

Flyback generator 3

GND

Output

5. U101 ： Tuner

PIN Function

1 Nc

2 Tu

3 Rf agc

4 SCL

5 SDA

6 Btl

4

5

Inverting input

Supply voltage

Flyback generator

Ground or negative supply

Output

PIN Function

7 +5V

8 IFA1

9 IF AGC

10 IFD 1OUT

11 IFD 2 OUT

6. Test point Waveforms

2.6Vpp

H

R2J10165GC

95Vpp

H

CRT KR

1Vpp

V

R2J10165GC

1.2Vpp

H

R2J10165GC

95Vpp

H

CRT KG

0.8Vpp

V

R2J10165GC

3.8Vpp

H

R2J10165GC

95Vpp

H

CRT KB

1.3Vpp

R2J10165GC

Symbol

Poutput supply

Input stage

2.5Vpp

H

R2J10165GC

0.9Vpp

H

9 Non-inverting input 2

PIN Function

6

7

R2J10165GC

Output stage supply

Non-inverting input

2.5Vpp

H

R2J10165GC

5Vpp

H

R2J10165GC

9


7. IC voltages

R2J10165G

PIN 1

V 0

2 3 4

0.02 4.9 0.03

5

0

6 7 8 9 10 11 12 13

4.72 0.04 0.15 2.05 8.04 2.99 2.36 3.2

14

5

15 16

0.83 0.93

PIN 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

V 0 2.04 1.15 1.15 2.97 3.2 0 3.76 3.91 5.59 2.28 8.73 3.29 1.97 5 2.73

PIN 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48

V 5.68 2.86 0 2.74 0.17 1.47 1.47 2.53 3.09 5 3.3 3.45 2.4 3.43 3.15 3.43

PIN 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64

V 2.47 8.03 2.57 2.49 2.59 8.87 0.42 4.9 4.94 4.95 3.82 1.96 0.33 2.9 4.95 4.94

PIN 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80

V 4.95 0 0.16 4.95 0 1.76 4.95 4.95 4.94 4.83 0.03 4.95 3.52 3.7 3.58 3.73

STV9302A

PIN 1 2 3 4 5 6 7

V 2.993 26.8 14.57 0 1.96 26.05 2.991

TFA9800J

PIN 1 2 3 4

V 2.15 0 7.53 7.5

24C16

PIN 1

V 0

2 3

0 0

5 6 7 8 9

0 7.51 15.48 13.93 2.122

4 5 6 7 8

0 4.95 0 3.52 3.58

8. PURITY / CONVERGENCE ADJUSTMENT

10


PURITY ADJUSTMENT

1. Demagnetize CRT with the demagnetizer.

2. Loosen the retainer screw of the deflection yoke.

3. Remove the wedges.

4. Input a green raster signal from the signal generator, and turn the screen to green raster.

5. Move the deflection yoke backward.

6. Bring the long lug of the purity magnets on the short lug and position them horizontally. (Fig2)

7. Adjust the gap between two lugs so that the GREEN

RASTER will come into the centre of the screen.

(Fig. 3)

8. Move the deflection yoke forward, and fix the position of the deflection yoke so that the whole screen will become green.

9. Insert the wedge to the top side of the deflection yoke so that it will not move.

10. Input a crosshatch signal.

11. Verify that the screen is horizontal.

12. Input red and blue raster signals, and make sure that purity is properly adjusted.

Long lug

Short lug

CRT

WEDGE

DEFLECTION YOKE

P: PURITY MAGNET

4: 4-POLES (convergence magnets)

6: 6-POLES (convergence magnets)

Fig. 1

P

4 6

P/C MAGNETS

PURITY MAGNETS

Bring the long lug over the short lug and position them horizontally.

Fig. 2

(FRONT VIEW)

GREEN RASTER

CENTER

Fig. 3

11


STATIC CONVERGENCE ADJUSTMENT

1. Input a crosshatch signal.

2. Using 4-pole convergence magnets overlap the red and blue lines in the center of the screen (Fig. 1) and turn them to magenta (red/blue).

3. Using 6-pole convergence magnets overlap the magenta (red/blue) and green lines in the center of the screen and turn them to white.

4. Repeat 2 and 3 above, and make the best convergence.

DYNAMIC CONVERGENCE ADJUSTMENT

1. Move the deflection yoke up and down and overlap lines in the periphery. (Fig. 2)

2. Move the deflection yoke left to right and overlap the lines in the periphery. (Fig. 3)

3. Repeat 1 and 2 above, and make the best convergence.

After adjustment, fix the wedge at the original position.

Fasten the retainer screw of the deflection yoke.

Fix the 6 magnets with glue.

(FRONT VIEW)

Fig. 1

(FRONT VIEW)

RED GREEN BLUE

BLUE

GREEN

RED

BLUE GREEN RED

Fig.2

(FRONT VIEW)

RED GREEN BLUE BLUE GREEN RED

RED

GREEN

BLUE

BLUE

GREEN

RED

Fig. 3

RED

GREEN

BLUE

12


9. DVD Part: Introduction of MTK1389D maintenance

NOTE: MTK1389D is a type of LSIC for DVD decode .MTK1389D IC consists of

RF,SERVO,DSP,DECODE,VIDEO DAC and AUDIO DAC.

1. Under normal power supply conditions, the maintenance plan for MT1389D mono-chip is: first the reset circuit resets the MT1389D, after the crystal oscillator circuit gave the clock signal to MT1389D, MT1389D will start the initialization check for Flash 、 E

2

PROM 、 SDRAM, after everything is checked to be normal, it will start initialization check for built-in Audio DAC, servo and motor Driver IC .

2. If the all the a.m. parts are good, then MT1389D will send signal to motor Driver to drive the servo system ， pick up then to generate DVD light for collection, tracing the main shaft to check if there is any disc, and confirm if it is CD format or DVD format disc. If the disc is in DVD format, the system will read the data from the disc directly; if it is in CD format built-in servo will drive the CD laser to send out CD light and read the data, the data then will be amplified through built-in RF amplifier and sent to MT1389D decode part for data processing, released by MPEG and resolved into video data and audio data, then they will be returned to analog signals through built-in VIDEO DAC 、 AUDIO DAC.

Decoder section

3.

1 ）

There is power supply, clock and reset, but the system does not work.

Check if all the address wires required for FLASH are exist, and if they are in normal status, especially check if the A0~A15 of FLASH have normal signals, if there aren

’ t, then inspect MT1389D to see if there is faulty soldering. If there are normal signals at A0~A15, check if the address data signal of MT1389D and SDRAM is normal. If it is normal, then check the signal at A16~A19 of MT1389D; if there are also signals, then check the video output wires and AV filter circuit; if there is no signal, then check the corresponding pins

4.

1 ） of MT1389D to see if there is any short circuit, break or faulty soldering.

System in normal operation, but the audio has no sound.

Because the AUDIO DAC is built in MTK1389D IC.you need to check the lower passing amplifying circuit and the MUTE circuit at the back of the LPF circuit. Also check if there is any power supply to the LPF circuit.

2 ） Check if the power supply voltage required for playing is at normal level.

Servo Section

5. After the LOGO of the machine shows normally, there is no OSD display. This problem mainly is caused by the abnormality built-in RF and servo, possible problems may be:

1 ） Built in RF and its surrounding circuits have problems.

2) Servo part of MT1389D has problems.

6. OSD display is normal ， while there is no action of servo part feeding motor does not work, main shaft does no turn, possible fault status are:

1) The corresponding signals giving by MT1389D to DMSO 、 FMSO are missing, the reason may be the problem of MT1389D or the communication between MT1389D and motor Driver IC SA5668.

2) Not output from Motor Driver, the reason may be the problem on motor Driver or its corresponding circuit.

7. Servo part in good status, while there is no pick up action （ no light, no focus ）

1 ） No light, check the power supply power supply for pick up , or the light producing driving circuit to see if they are in normal status.

2 ） No focus, check MT1389D to see if there is signal output from FOSO 、 TRSO.

Secondly, check motor driver to see if there is F+ 、 F、 T+ 、 T-signal output.

Thirdly, check the external corresponding circuit of the motor driver to see if there is any problem.

8. All the servo part has action, while it cannot read out the disc

1 ） Check MT1389D if there is RF net picture output, if there isn

’ t, then it must be the problem of

MT1389D and external surrounding circuits, it there is output, then it might the problem of MT1389D and its surrounding circuits.

2 ） There is RF signal ， but not in normal status ， then check MT1389D and surrounding circuits.

3 ） Everything is normal, but the disc cannot be read out, check MT1389D and its surrounding circuit

13


Sincere Forever

Haier Group

Haier Industrial Park, No.1, Haier Road

266101, Qingdao, China http://www.haier.com

14


Memorex MT2025D - 20" CRT TV Service Manual

SERVICE MANUAL

Colour Television

Haier model:

21F7A

Customer model:

MT2025D

FEATURES

CONTENTS

1. SAFETY

PRECAUTIONS

3. REPLACEMENT OF MEMORY IC

4. SERVICE ADJUSTMENT

A3. Error Detection Process

Adjustable Items

5. ICs functional description

6. Test point Waveforms

7. IC voltages

8. PURITY / CONVERGENCE ADJUSTMENT

9. DVD Part: Introduction of MTK1389D maintenance

Sincere Forever

Haier Group

Haier Industrial Park, No.1, Haier Road

266101, Qingdao, China http://www.haier.com

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