LENCO _tft700_sch Datasheet

Service Manual of TFT-700

Damageable Parts：

CSC2600, B1203,CPU, High-Voltage fuse N25,High-Voltage Circuit Audion, Transformer, On/Off switch, Flat Cable, LCD Panel

1. Scenario: No sound, No picture, No light

Whether Power LED is working in RED

YES

Press POWER button and test pin 29 of CPU, see if voltage change from 0～5V or 5～0V

NO

Test whether CPU 5V power supply is OK

YES NO

Is Button input pin voltage right?

NO

Is CPU C1815,B1203 and

Is IC M61260pin32 voltage OK?

NO YES

YES

Test circuit of CPU pin 22 to IC M61260 pin 32

NO NO YES

Is IC M6260pin12 voltage right?

back power circuit shorted?

Original Cause

Change B1203 C1815 to avoid short

Is all circuit coming out from power supply voltage right?

Change CPU

NO YES

YES NO

Is IC M61260 pin 12 power supply circuit OK?

Is there High - Voltage output?

NO NO

YES

Change LCD Panel

IC M61260 Bad

Repair Power supply or relative circuit.

Check High-Voltage circuit N25 broken?

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Change High-voltage circuit audion or high-voltage transformer

Service Manual of TFT-700

2. Scenario: Abnormal Color

Is IC M61260 pin14,15,16 output voltage OK?

NO

Is IC M61260 has power supply?

YES

Is IC CSC2600 Pin6,8,9,29,32,35 voltage OK?

YES

NO

YES

Change Circuit cable of LCD Panel

Change defect parts in loop circuit.

Change IC M61260

NO

Is circuit around IC CSC2600 OK?

YES

Change IC CSC2600

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Service Manual of TFT-700

3. Scenario: No Sound, with Light, Black Screen

Is power supply to IC M61260 pin

3,4,12,39,40 alright?

NO

Check Power Supply

YES

Is IC M61260pin 24,26,27,34 working alright?

NO

Is CPU circuit and relative circuit

YES

around IC M61260 pin 34 alright?

Is voltage of IC M61260pin 14,15,16 alright?

NO

Change IC M61260

YES

Is voltage of IC CSC2600pin 6,8,9 alright?

NO

Check circuit around IC CSC2600

YES

Change LCD Panel

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Service Manual of TFT-700

4. Scenario: Horizontal and Vertical Not in Sync

Is IC M61260+5V +8Vwell powered?

NO

Repair Power Supply

YES

Is relative circuit around IC M61260 pin 5, 11 alright?

NO

Check relative circuit around pin 5,11

YES

Check circuit around IC 4001（H/V Sync circuit）

YES

Check LCD Panel pin 6 alright?

YES

Change Flat Cable

NO

Change LCD Panel

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Service Manual of TFT-700

5. Scenario: White Light

Check switches power +5V +8V +17V –15V alright?

NO

Repair Power and check following circuit shorted or overloaded?

YES

NO

Check IC CSC2600 +5V、-7.5V power supply alright?

Check power supply

YES

Check IC CSC2600 alright?

YES

Change Flat Cable of LCD Panel

NO

Check LCD Panel power +5V +17V –15V Alright?

Check power

NO

supply loop circuit

YES

Change LCD Panel

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Service Manual of TFT-700

6. Scenario: No Signal

Check +40V input alright?

NO

Check 40V loop circuit

YES

Check whether CPU pin 40,41,42 have band switching voltage, Pin8 output voltage alright?

NO

Change CPU

YES

Check tuner +5V power supply AGC voltage VT tune voltage alright?

NO

Check tuner +5V power supply AGC voltage VT tune voltage alright?

YES

Check Amplify Circuit and circuit around IC M61260pin 60,62 alright?

NO

Check Amplify Circuit and circuit around

YES

IC M61260pin 60,62 alright?

Change Tuner

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Service Manual of TFT-700

7. Scenario: Channel Storage unavailable

Check 32V tuning voltage stable?

NO

Repair Tuning circuit

YES

Check CPU pin 2 voltage stable?

NO

Check CPUpin2 relative circuit

YES

Change Tuner

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Service Manual of TFT-700

8. Scenario: With image, no sound or little sound, or sound distortion

Check speaker circuit broken?

YES

Change Speaker

NO

Check Amplifier IC 386 alright?

YES

Change IC 386

NO

Check IC M61260 pin 50,51,54 alright?

YES

Check IC M61260 Pin 51 to IC 386 pin 3 parts

NO

YES

Change parts around pin 50,51,54

Change IC M61260

NO

Change defective Parts

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Service Manual of TFT-700

g

9.Scenario: Dark Light

Is contrast and lightness in minimum

NO

?

settin

Check all power supply circuit

YES NO

Check power supply circuit

YES

Adjust settings to normal

Adjust Mainborad BRI potentionmeters, any changes on screen?

YES

Adjust to normal.

NO

Check circuit around IC CSC2600

YES

Change IC CSC2600

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Service Manual of TFT-700

10. Scenario: With image, with Sound, no character or dismal characters

Check CPU Horizontal/Vertical Sync input pulse alright?

NO

YES

Color Character not right

YES

查行场同步电路

Check CPU pin 33,34,35,36 to IC M612160 pin 21,22,23,24

Change loop

NO

circuit parts

Change CPU or IC M61260

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Service Manual of TFT-700

11. Scenario: No sound or no image in AV

Check AV Cable alright?

NO

YES

Check input jack

NO

YES

Change AV cable

Change input jack

Check Audio & IC M61260 pin 53 loop circuit, check Video & IC M61260 pin 38 loop circuit

YES

Change IC M61260

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Service Manual of TFT-700

12. Scenario: No up/down, left/right revert function

Use Remote button button

Check CPU pin 1,11, whether voltage changes from

0～5V or 5～0V, pin 15,16 voltage changes from 0～5V or 5～0V

Change another remote

NO

control to test

NO

YES

NO

Check CPU pin 1,11,15,16 to LCD Panel flat cable pin 16,17,18,19 broken?

Change IR on Remote

Change CPU

NO

Change LCD Panel

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