Servicing a SONY DAT machine (Pictorial)

Discussion in 'Tape' started by SaSi, Sep 17, 2008.

  1. hdrobien

    hdrobien Active Member

    Messages:
    411
    Location:
    France
    I just want to check my theory about tape trembling.

    You can "open" the mecha to check the felt pads (used for play back tension) and the brakes, but I believe the problem is elsewhere.

    The reels generate themselves some back tension as there is a spring underneath (part #364 on the service manual).

    But lets be honest, I would not bother too much about the "tic tic" sound if everything is fine.
     
  2. d-roby

    d-roby Member

    Messages:
    69
    Location:
    Genova- Italy
    Thank you, but i would like to fix it ;-)
    i noticed that the right reel turned by hand has a little friction ( and it should be correct) but the left one turns freely.. Brakes?
     
  3. hdrobien

    hdrobien Active Member

    Messages:
    411
    Location:
    France
    It depends of the mode the deck is engaged in.

    Each reel has several type of brakes:
    - rubber ring to stop them from rotating after fast-forward and rewind. Strong friction (you can feel the teeth of the gear on which it relies). Activated with a plunger.
    - felt pads for back tension during play and reverse play. Medium friction. Activated with a plunger.
    - self friction with the spring underneath. Very light friction. Permanent.

    Some say that the felt pads generate some friction even when they are not "activated" by the plunger.

    AFAIR, in stop mode, the rubber brakes is only active on one reel.
     
  4. d-roby

    d-roby Member

    Messages:
    69
    Location:
    Genova- Italy
    I checked the reels , brakes and clutch..everything seems to be fine..
    But the problem is still present:
    expecialy in rewind, the tape, as you suspected, is trembling, and i think the tic-tic is a solenoid,.. may be like a fast "start and stop" that of course change the speed of the tape..
    BUT... i i use a blank tape FFWD and REW is ok... uhm....
    is the solenoid adjustable?
    Many thanks
     
  5. hdrobien

    hdrobien Active Member

    Messages:
    411
    Location:
    France
    No I don't think it can be a soleinoid, which sounds more like "clac".

    I am pretty sure it is just the tape as it runs especially fast.
     
  6. d-roby

    d-roby Member

    Messages:
    69
    Location:
    Genova- Italy
    If i reduce the "torque" with the trimmer, the tit-tic is less frequent , or disappear, but ,of course, the speed of rewinding is low....
    It is a pity, as record and playback is fine.( i tested again).and the sound is very good, too
     
  7. hdrobien

    hdrobien Active Member

    Messages:
    411
    Location:
    France
    If it sounds good and rewind fast and secure, just enjoy !
     
  8. Dimitris_

    Dimitris_ New Member

    Messages:
    1
    Hi Everyone!

    With the help of this thread and the service manual I almost fixed a Sony DTC-55ES that I bought from eBay not very cheap with description “For parts or not working”


    The machine had multiple problems:

    Broken rotary encoder gear. Fixed with superglue

    Old, sticky grease everywhere in mechanical parts. I remove it and apply new lubrication.

    Bad pinch roller. I use another from an IBM DDS computer drive.

    2 bad caps in RF board.

    And it was completely uncalibrated. Not possible the playback tapes written from this machine to my computer DDS drive (with special firmware in order to read DAT tapes) and not possible to play tapes written from my DDS drive to Sony.

    After 2 days fighting with the calibration guides, finally it’s ok!


    Now I have 2 more problems and I need some help…

    First problem is that sometimes the take up reel not starting when I press the play button and the tape get jammed inside the machine. At the same time the machine seems to sluggish to rewind the tape and I think these two are related.

    Another clue is that the brake pads of the take up reel have more wear from the other ones…


    Second problem is that the machine have a fade in / fade out function.

    When using the headphones this is working as expected. But when using the optical digital out it’s not working…
    Only the counter starts and the bars shows the progress of the fade in or out but the sound volume doesn't follows... its on or off

    I don’t believe that it’s supposed to be like this.


    Any help guys???


    Thanks
     
  9. Blink1

    Blink1 New Member

    Messages:
    1
    Hi,

    Mine has the same issue with the transport and it might be cassette related: try a different tape once. Or it may not as sometimes it works ok with the same cassette sometimes it doesn’t (Maxell 90 here).

    The fade as far as I know only works over analog, check your manual please.
     
  10. hdrobien

    hdrobien Active Member

    Messages:
    411
    Location:
    France
    @dimitris

    Regarding your first problem, I would suggest to replace the felt pads of the "lever (slider) assy" (part #562 on the schematics). Of course it implies that previously you cleaned all old grease.
     

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