Denon DN-790R Belt Replacement and Capstan Motor Troubleshoot - Speed/ Wow & Flutter Instability

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  • Опубліковано 12 гру 2024

КОМЕНТАРІ • 17

  • @SDsailor7
    @SDsailor7 2 роки тому +2

    You can now take that transport apart with your eyes closed ha!
    Now you are an expert on this transport.

    • @asbcustom
      @asbcustom  2 роки тому +1

      Probably true, Denon made this one easy, not all are like this.

    • @SDsailor7
      @SDsailor7 2 роки тому

      @@asbcustom I wanted to ask you, does the motor with the small belt always running while the transport is engaged? I opened up yesterday and i was activating the "finger" switches on the left and i noticed that the motor was only running intermitently or not at all so i sprayed the switches with deoxit but that did not help. Today i will replace the small belt with a square generic belt that i have (bought a bag of square belts different sizes from amazon a while back)

    • @asbcustom
      @asbcustom  2 роки тому +1

      @@SDsailor7 The control motor should operate to place the head stack in position and then turn off. I think you'll see how it should work when the new belt is installed, the old one is probably so loose that it can't fully engage.

    • @SDsailor7
      @SDsailor7 2 роки тому

      @@asbcustom Ok. Thank you
      Hopefully that will be the case. Will let you know how it turns out

    • @Chuncy566
      @Chuncy566 9 місяців тому

      ​@@asbcustomwould you do a csm 131 (no other letters) tear it down to the bare frame & then put it back together showing us all the parts how they function, how they fit in there, and then how it is working,that would be great, thank you

  • @narendrand7013
    @narendrand7013 2 роки тому

    Thank you for this video. While searching for the belt change saw yours. Got the confidence to open up and do it on my own. And it worked.😊

    • @asbcustom
      @asbcustom  2 роки тому

      Good Job and thanks for your comment!

  • @Tim3ru
    @Tim3ru 2 роки тому

    Hi, I do believe for the mechanisms that use this type of motor it's as good as it's gonna get +/- depending on build quality. Maybe how it jolts and doesn't have 'smooth torque' as the commutator goes around and makes contact with the brushes... Anyway, that extra cap helps smooth it a bit I'm sure, simply don't trust those little ones that also get hot inside the motor case. I'm struggling myself with this on two decks. I am working on a regulator circuit around LT1970 that might improve things but I don't actually expect it to do much, I think it's inherent to the brushed motor capstan drive mechanisms, we'll se. But first I need to replace two SMD electrolytic caps on the capstan drive board of my JVC TD-V1050 (axial flux stepper), hope to get to them next couple of weeks. Good job keeping 'them decks neat and working, very tedious job indeed and thanks for sharing!

    • @asbcustom
      @asbcustom  2 роки тому +1

      Thank you for your comments.
      I think you are correct and hope your regulator circuit works, please post your results if you can, I'd love to know how it worked out. I've found that with sufficient flywheel mass, the electronic regulation is supplemented by mechanical inertia and is really quite good but must have accurately ground belts. On the two Tascam series decks that I can still get factory belts for, I can routinely achieve the stated .04% flutter or better. This one ended up around

  • @slawomirbalon7246
    @slawomirbalon7246 2 роки тому

    Hi, exelent video.
    I try to repair the capstan motor for Pioneer PD-S740S. The deck was standing not used for years and belts become a liquid... After belts change I noticed twice more speed of motor than it meant to be. Motor goes very hot after few minutes of work even if it runs alone. I took apart the motor, cleaned it but nothing changed. The DC motor controller inside is build with AN6605 and it goes hot very quickly. Whole thing is powered from 12V stabilized from simple 7812. Motor without controller draws around 350mA @ 6V without any load. I'm not sure is it ok or must i look for new motor? Could you please give any advice?

    • @asbcustom
      @asbcustom  2 роки тому

      Thank you for watching.
      It's hard to say, a lot of things can go wrong when something sits around unused for years?

  • @musicstevecom
    @musicstevecom Рік тому

    might want to put in a 10 turn pot?

    • @asbcustom
      @asbcustom  Рік тому +1

      Indeed yes, I installed a 25 turn at some point in the video.

    • @musicstevecom
      @musicstevecom Рік тому

      @@asbcustom did it help the wow and flutter and spikes

    • @asbcustom
      @asbcustom  Рік тому +1

      @@musicstevecom The trim pot? Not with wow and flutter, no, but it helped a ton while calibrating the speed. These are impossibly touchy from the factory, the upgrade is a major improvement.