资源描述：
《CD-ROM 电路原理.ppt》由会员上传分享，免费在线阅读，更多相关内容在行业资料-天天文库。
1、48SBHARDWARETRAININGBYOSDPETERCHANGMT1198BA6849BA5954SpindlePickupMT1136FLASHROMDRAMIDEU6ThechipisaCMOSopticalpick-upheadanalogsignalamplifier.ItcomposesofRFamplifiersandlowpassfiltersusedtoextractthehighfrequencyEFMsignalandlowfrequencyservosignals.ThechipisaCD-ROMsystemcombochip.
2、Itcomposesofhostinterfaceprocessor,buffermemorycontroller,EFMdataprocessor,upinterface,FlashROMinterface,built-inDACandServocontrolinterface.Theoutlineis208-pinQFPpackage.Thechipisa4channeldriverforopticaldiscmotordriver.ItcomposesofActuatordriver,sledmotordriverandloadingdriver.Th
3、echipisa3phase,full-wavepseudolineardrivingsystem.Thechipishighspeed5voltFastPageDRAMorganizedas64Kbit*16I/OandfabricatedwiththeCMOSprocess.Thechipisa512Kbit,5voltonlyCMOSflashmemoryorganizedas64K*8bitsU9U5U4U7U8LOADERCD-ROMBLOCKAUDIO33.8688MHzMasterclockTHESTEPOFSREVOONServo_onSer
4、voon?&&focusok?Initial_Dspoffset_adjFocus_onREADYSpindle_onradial_onCal_status!=true?AutocalibrationRead_positionREADYSetspeedandwaitstableSpin_status=onReturnreadyReturnreadqerrorReturnfocuserrorReturnreadyNOYESNOYESYESTESIGNALEFABCD(A+C)-(B+D)FocusE-FTrackingCorrecttrackingEFABCD
5、(A+C)-(B+D)FocusE-FTrackingINFOCUSABCDABCDABCDDisctoonearInfocusDisctoofarFESIGNALRFSIGNALABCDA+B+C+DRFSIGNALI3I110THESTEPOFDEBUG當CD-ROM發生問題時,應如何判斷是那麼的問題1.先判斷是LOADER或PCB的問題?2.如果是PCB的問題,是那一個BLOCK?3.PCB完全沒有任何動作,請CHECK電源或FIRMWARE是否正常.4.SPINDEL不轉或轉速不夠,這可能是MOTORDRIVERIC(BA6849FM)有問題.5.不
6、能TRAYIN/OUT,可能是4CHIC(BA5954FP)有問題.6.不能READY,可能是MT1136或BA5954有問題.7.IDE掛不上,CHECKIDECONNECTOR及DRAM.8.AUDIO沒有輸出,CHECKAUDIOAMPLIFIRER(3414).PCBDEBUG1.當PCB完全沒有任何動作(LED沒亮)時:(A).檢查各電源是否正常:12V,5V及3.3V如有不到正常位準,可能回路中有地方跟Ground有Short現象或是零件壞掉所造成,另外3.3VRegulator(U1)有可能會因為電源的突波而壞掉,這也會造成5V及Ground的
7、Short(B).檢查Resonator(Y1)是否有震盪,正常的波形如下(測量U956pin)(C).檢查FlashROM(U4)是否有成功燒錄,是否有正常動作如動作正常則波形如下PCBDEBUGADDRESSBUSDATABUS(D).檢查各IC的RESET信號是否有送出:PCBDEBUG這個RESET信號是由RC放電產生的,TIMING是15ms,實際上大概10ms就會到達Triggerlevel.PCBDEBUG2.LaserDiode沒有動作時:(A).檢查J4是否有Short(B).檢查FPCCable是否斷裂(C).檢查J4與FPCCable是
8、否接觸不良(D).檢查PCB及電路是否正常動作,La
