Samsung HLRS078WX/XAA Service Manual page 41

Troubleshooting
6-1-1 Video Circuit Error Checking
m Basics:
- The DDP1011 on the DMDboard hasa featureto display internaltest patterns.
- DNle,which is an end port in the digital board,has a featureto display internaltest patterns.
- The analogboardsends signalsto ADV7401on the digitalboard.
- The analogboard is thefirst output and the digitalboardis the secondone,followedby DMD,which is the final one.
[] DiagnosisBy Module
1.AccessServiceMode
(In Standbymode, press"Mute","1", "8", "2" and "Power"to turn the screenon and enterservicemode)
2. Checkif thereis an error in the DMDboard
DDP1011 -->TEST PATTERN _ Pressthe rightarrowkey:
Optionsof FULLWHITE,BLACK,RED,GREENand BLUEPATTERN are displayedon the screen.
If "Pattern"doesnot appear,this is a DMDboarderror.
3. Checkif thereis an error in the digitalboardbeforethe DMD.
Whenthe DMDboard hasbeen determinedto be error free basedon the test patterns:
FACTORY MODE_ DNle _ TEST PATTERN normaldisplay:no error in the digitalboard.
If "Pattern"doesnot appear,you haveto checka Analogboardfirst, and checka DMDBoardsecond,next checka Digital
Board.
4. Checkif thereis an error in theAnalog Board.
Checkfor a powersignalfrom the analogto the digitalboards.(Seethe circuitdiagrambelow).
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SamsungElectronics 6-5