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Denon DCD920 CD Player Service Manual help

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    Denon DCD920 CD Player Service Manual help

    Hi all,

    I'm trying to track down a service manual for a Denon DCD920 but am drawing a blank. Can anyone point me in the right direction?

    Many thanks.

    Neville

    #2
    Re: Denon DCD920 CD Player Service Manual help

    What do you actually need, as there is the schematic on the internet.

    Comment


      #3
      Re: Denon DCD920 CD Player Service Manual help

      This CD had a non opening drawer which has now been lubricated and fixed.

      It spins up a CD but I have no audio output or track details on the display.

      I connected a scope to one of the test points which started it playing.

      So i'm wondering if one of the adjustment pots needs tweaking - but which one?

      Attached Files

      Comment


        #4
        Re: Denon DCD920 CD Player Service Manual help

        No pots need to be adjusted, Did you find the schematic?
        I connected a scope to one of the test points which started it playing.
        It might be more help if you said WHICH test point you touched.

        Comment


          #5
          Re: Denon DCD920 CD Player Service Manual help

          Just brought it back to the bench and I can't seem to repeat the phenomena.

          I'm pretty sure I touched the FEO pin on TP101.

          It doesn't want to play or read the TOC.

          The CD spins. No disk data is displayed. Occasional focusing? heard.

          Comment


            #6
            Re: Denon DCD920 CD Player Service Manual help

            Do you get any eye pattern on tp102-1 (HF)? I would check that the spindle motor is not sticking and spins freely. if it spins slow it might not read. You did clean the lens ?

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              #7
              Re: Denon DCD920 CD Player Service Manual help

              Yes I've cleaned the lens.

              When it did play the speed seemed 'normal'

              Below is the trace from tp102-1 (HF)

              Attached Files
              Last edited by Nevillet; 02-09-2021, 03:17 PM.

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                #8
                Re: Denon DCD920 CD Player Service Manual help

                That waveform is not very good, that's why its not reading, Have you checked that the +&-5v and +&-10v are ok and clean.

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                  #9
                  Re: Denon DCD920 CD Player Service Manual help

                  I measured the +/- 5V at the regulators and they are both stable and on target.

                  I need to take a closer look for the +/- 10V rails. There were no obvious regs like the 5V ones.

                  It's a bit late here and my bed beckons. Back tomorrow.

                  Comment


                    #10
                    Re: Denon DCD920 CD Player Service Manual help

                    Originally posted by Nevillet View Post
                    I measured the +/- 5V at the regulators and they are both stable and on target.

                    I need to take a closer look for the +/- 10V rails. There were no obvious regs like the 5V ones.

                    It's a bit late here and my bed beckons. Back tomorrow.
                    The +/- 5 volt regulators are supplied by the +/- 10 volts, so check the input to the regulators, Since you have a scope, check the ripple as well. The +/- 10v supplies the spindle motor drive.
                    I assume you have the schematic.
                    Last edited by R_J; 02-09-2021, 05:17 PM.

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