Trouble Diagnosis And Repairing Method For Representative Symptoms - Daewoo DP-42SM Service Manual

<Symptom.4> No SOUND
<Symptom.5> The Set does not operate normally. But, after turn off AC Power, if turn on again, it
operates normally again.
<Symptom.6> Remote Control or KEY does not operate
<Symptom.7> POWER SHUT DOWN occur (refer to Service Manual I. 9-3 )
(3) Representative Symptoms caused by bad Connection between PCBs.
[Note] Dust or extraneous materials is most likely to cause bad connection. Most of this case, it can
be solved if using soft brush, AIR FRESHER, or breath to clean dust or extraneous materials or
reassembling the Connector.
* Refer to Chapter II for Symptoms of other parts with exception of VIDEO, JACK PCB and POWER
PCB Trouble.

9-3. Trouble Diagnosis and Repairing Method for Representative Symptoms

(1) When POWER SHUT DOWN occurs
<1> Definition of SHUT DOWN
- When LED color is green, you can t hear power operating sound. (Red : STAND BY, Green :
Operating)
- When turn on AC switch and then push POWER button of remote controller, power relay do
not operate normally, and POWER operating sound can not be detected.
<2> Trouble Repairing Procedure
- As shown in Fig. 5, first check which of LOW VOLTAGE part or HIGH VOLTAGE part has
a trouble.
- If LOW VOLTAGE part is broken is checked, as shown in Fig. 6 diagnose the SET and then
replace the broken PCB.
- If HIGH VOLTAGE part is broken is checked, as shown in Fig. 7 diagnose the SET and then
replace the broken PCB.
- <Note.1> When disconnecting/connecting connectors, you must turn OFF the AC power and
check the direction/position of them before working.
- <Note.2> If you turn the SET ON with POWER CONNECTORS of Z-SUS PCB and Y-SUS
PCB (P101A, P102A, P103A) disconnected, although you turn the SET OFF again,
Remaining Voltage still exists in the POWER PCB. Therefore assemble the connectors
several minutes after. Or, check the Remaining Voltage (Vsus, Vadd) by multimeter. If
Vsus is less 10V, connect connectors. Connecting connectors with the Remaining
Voltage (Vsus, Vadd) over 10V could generate sparks and be dangerous to Operators or
SET.
(2) When weak Discharge exists on screen but OSD screen can not be seen
<1> Definition of this symptom
- When the set was turned on, screen is BLACK but Weak Discharge (luminescence) exists.
- When OSD does not show on screen and the set does not respond to remote controller or KEY
panel s any button.
<2> PCB CHECK PRIORITY
- VIDEO PCB
-35-
Trouble shooting