Text preview for : CW28C73NS_4.pdf part of Samsung chassis KS3A service manual



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Plug in Power Cord

Samsung Electronics
ON Check LED lamp OFF Normal Normal Check and Replace the MICOM Normal Check and Replace IC903 Check IC901 MICOM Input Voltage Abnormal Normal Abnormal Check the MICOM Power #59 With Remote Controller Replace the MICOM Abnormal Replace Q908 Normal Normal Check IC802, IC803 Replace IC802, IC803 Normal Check IC201S VDP H-OUT #50 Abnormal Replace IC201S Normal Check Q401 H-TR Replace Q401 Normal Check 135V Line Check PC801S, IC801S Normal Replace FBT Abnormal Abnormal Check R828 and D805 Abnormal Check IC801S and FP801S Normal Check and Replace R828 or D805 Abnormal Check IC804 Input Voltage Abnormal Normal Check and Replace IC804 Check D801 and D811 Abnormal Abnormal Replace D801 or D811 Check IC903 3.3V Regulator Input Voltage Normal Replace Q908

5-1 No Power

5. Troubleshooting

Abnormal

Check MICOM IIC #5, #6

Check Level Shifter Q909, Q910 Output(If 2N7000 Output has the DC Component over 0.7V, it is broken)

Normal

Abnormal

Check MICOM IIC #2, #3

Abnormal

Replace Q909, Q910

Normal

Check IC902 EEPROM

Replace EEPROM(IC902)

Normal

Check IC201S

Note : When you check whether any component is normal, you must let the output pin be open in order not to be affected by the side of output.

Troubleshooting

5-1

No Picture, but sound is in normal operation

Normal

Turn the VR of FBT, higher screen voltage and Check the Deflection is in Normal Operation (If the deflection is in operation, flyback signal is appeared)

Abnormal

Normal

Check CRT PCB RK, BK, GK

Abnormal

Normal

Check IC201S #31

Abnormal

Check Heater Voltage Abnormal Normal Check CRT and FBT

Check HIC202, HIC203, HIC204 Output

Abnormal

Check 8V Check IC201S #63 or #59 Normal Abnormal Normal Normal

Abnormal

Check DZ202

Abnormal

Check CRT and FBT

Normal

Check IC803 Replace IC201S Check 200V, 16.5V Line Check Tuner CVBS Output Check IC301

Replace DZ202

Replace IC201S

5-2 No Picture

Troubleshooting

5-2

Samsung Electronics

Troubleshooting

5-3 No Sound

No Sound, but Picture is in normal operation

Normal

Check the CN602 Connection and Signal

Abnormal

Check the Speaker Wire Connection

Normal

Check 14V Line

Abnormal

Check IC602 #7 (If the pin is in low state, Sound is mute) Normal

Abnormal

Check FA803S

Check D816, Q906 Check IC601 #24, #25 Normal Replace IC602 Check IC601 Input Voltages (5V,8V) Normal Check the coils around IC601 Check IC601 Input Signal Normal Replace IC601 Check the Tuner Abnormal Abnormal Abnormal

Samsung Electronics

5-3

MEMO

5-4

Samsung Electronics