Daewoo DP-42GM, Service Manual

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Main PCB Trouble Diagnosis
9-4. Y-SUS PCB Trouble Diagnosis
1. After detach SCAN PCB from Y_SUS PCB, turn on the power.
2. If turn on normally, check SCAN PCB.
Detach just SCAN PCB from Y-SUS PCB and perform DIODE TESTER measurement as
below.
NAME DIODE TESTER MEASURE DIODE TESTER MEASURE
1 Vpp + Open - Over 0.4V
Vss - +
2 Vpp + Open - Over 0.6V
TP - +
3 TP + Open - Over 0.5V
Vss - +
If SCAN PCB failure is still estimated after above DIODE TESTER measurement, connect only
one of SCANL and SCANH PCB to Y-SUS PCB and set POWER PCB’s condition to LOW-
Voltage. After that, perform DC-VOLTAGE TESTER Measurement as following table.
NAME DIODE TESTER MEASURE DIODE TESTER MEASURE
1 Vpp + Over 38V - Under -38V
Vss - +
2 Vpp + -0.8V - Under 0.8V
GND - +
3 Vss + Under -39V - Over 39V
GND - +
3. If SCAN PCB is normal and “Power Shut Down” happens, then disconnect P101A and then turn
on the power.
4. If power turn on normally, check Y-SUS PCB.
5. Disconnect P102A, P103A Connectors.
6. Check remaining voltage of P101A. Current model contains “Discharge Resistance” for
discharging High Voltage (Vsus, Vadd) remaining inside the POWER PCB. Therefore, when
dozen or more remaining voltage is measured, it could be POWER PCB failure.