Sharp DV-550U Service Manual

Also see for DV-550U: Technical manual

DV-550U11-3FLOW CHART NO.10 FOCUS TROUBLESHOOTING(2)Focus servo does not function.NoIs the FE waveform at pin(38) of IC707 present? Check lines between at pin(27) of IC303 and allYes the way up thru to pin(38) of IC707.Is the output waveform output at pin(43) of IC707? No Check the power circuit line of IC707.If OK, IC707 is defective.YesIs the focus drive waveform output from pin(17) or(18) of IC702?No Is the supply voltage of 8V fed to pin(21) of IC-702? If OK, IC702 is defective.YesIs the output waveform applied to pin(2) or (4) ofAB connector from IC702?No Check lines between the AB connector and allthe way up thru to IC702.YesCheck the connection of optical pickup cable.If OK, optical pickup is defective.FLOW CHART NO.11 LASER TROUBLESHOOTINGThe LASER fails light up.NoIs "H" level applied at pin(51) of IC303? The IC303 or IC707 is defective.Yes NoIs applied to the emitter of Q301? Check PC line.Yes NoIs applied to the collector of Q303? Check a "L" level at base of Q303, Q307.YesReplace Q307.No YesIs 2.3V applied to the collector of Q307? Is 2.9V applied to the base of Q307?Yes NoCheck between base of Q307 and all the way upthru to pin(52) of IC303.Is 3.3V and 2.3V applied to the pins(11) and (9) ofAB connector?No Check between Q303 and Q307 and all the way upthru to AB connector.YesCheck the AB connector.If OK, optical pickup is defective.Tray is not opened.Does it vary at IC504 (pin 94) when thetray open-/closing button is pressed?Is loading motor drive voltage outputto AG connector (pins 2 and 3)?Visually check the gear and so on ofthe mechanical section.Check between IC504 (pin 94) andtray open-/closing button.Is loading motor drive voltage outputfrom IC701 (pins 9 and 7)?Check between IC701 and IC504.Is 8V measured at IC701 (pins 3 and 8)?Replace IC701.Check 8V line.YesYesYesNoNoNoIs any signal input from IC504 (pins 70and 69) to IC701 (pins 2 and 4)?NoNoYesYesCheck between IC701 and AG connector.