Samsung PS42B430P2WXXH Service Manual

TroubleshootingSamsung Electronics 4-3■■ When the unit is repeatedly turned on and offSymptom - The SMPS relay is repeatedly turned on and off.Major ChecklistIn general, the SMPS relay repeatedly turns on and off by the protection function due to a defect on a boardconnected to the SMPS.- Disconnect all cables from the SMPS, operate the SMPS alone and check if the SMPS works properly and ifeach voltage output is correct.- If the symptom continues even when SMPS is operated alone, replace the SMPS.- If the symptom is not observed when operating the SMPS alone, find any defective assemblies by connectingthe cables one by one.TroubleshootingProceduresCautionWhen separating and connecting the cables such as CN810, CN809, CN808, CN807 of the Main SMPS, CN4701of the X Main Board, and CN5707 of the Y Main Board, a spark may be generated by the electric charge of thehigh capacity capacitor. Therefore, wait some time after disconnecting the power cord from the unit.Does the symptom continue whenconnecting the power after removingCN810 from the SMPS?Replace the Y Main BoardDoes the symptom continue whenconnecting the power after removingCN809 from the SMPS?Replace the X Main BoardReplace the Logic BoardDoes the symptom continue whenconnecting the power after removingCN807 from the SMPS?Replace the SMPS①②③YesNoNoNoYesYes