Servicing a SONY DAT machine (Pictorial)

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

  1. RMbA

    RMbA Member

    Messages:
    89
    I don't understand the reference to red and blue circles.

    On the lower half, I can see a black gear-arm with a white washer in place. The end of that gear arm is adjacent to the gear on a white gear-arm. Both have washers and seem to be moving freely. FWIW, the sliding mechanism seems to move freely.

    But I don't see the brake levers from this viewpoint.
     

     

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  2. hdrobien

    hdrobien Well-Known Member

    Messages:
    502
    Location:
    France
    Red circles show the shafts and axles to be cleaned from old grease.

    The blue circles show the washers that have to be "glued" with nail lacker (the left one on the white gear-arm is already missing). This part of the sliding mechanism is always fine. The problem is with the gears that drives it. When the transport is opened, these gears are on the other half (red circles).
     
  3. RMbA

    RMbA Member

    Messages:
    89
    Thought I already sent this reply, but maybe not because there's nothing after your last.

    I don't understand the references to red, blue, and green circles.

    I cleaned the two shafts, but my Q-tips didn't show any grease, etc. The gear assembly seems to have a little more inertia, but turning the gears seems to take a good deal more effort than trying to turn the black gear alone before disassembling the unit.

    The two washers were in place on the two gear-arms and the mechanism seemed to move freely and as it should (from what little I know!). The slider mechanism also moved freely.

    From this viewpoint, I don't see the brake levers to check the felt pads. Actually, I can't seem to see them from any view of the chassis. What am I missing here?
     
  4. RMbA

    RMbA Member

    Messages:
    89
    I don't see any colored circles.

    I'm also wondering about the switches in this assembly—whether they're working as they should. But I only see two (next to the large white pulley and belt that open the DAT loading bay.
     
  5. hdrobien

    hdrobien Well-Known Member

    Messages:
    502
    Location:
    France
    The colored circles are on the picture below.

    photo6_redimensionner_redimensionner.jpg
     
  6. RMbA

    RMbA Member

    Messages:
    89
    I guess the pix was there all the time, but I hadn't realized I had to move to the next page—noob!

    By the way, I had a three-head, three-motor Nakamichi many years ago—I think it was a 582Z (but not sure)—and I regret having sold that machine when my head was turned by CDs.

    Now I see brake levers and that the felt pads are in place.
     

     

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  7. RMbA

    RMbA Member

    Messages:
    89
    Well . . . it's put back together (which, although your directions were excellent, I regard as a minor miracle!). And although the deck still doesn't PLAY or FF or REW, and there's still a Caution, now the door will open when there's a tape inserted, which it would not do before. Sometimes when the tape is reinserted, the counter begins to count a couple of seconds, but then Caution reappears. Once the Caution comes on, it's necessary to power the unit off in order to get the ejection mechanism to work again and eject the tape.

    Do you think that switches might not be working properly and, if so, how do I find them?
     
  8. RMbA

    RMbA Member

    Messages:
    89
    Stop the presses! I cycled the door a dozen times and the unit is now working in the play mode! Now, all functions seem to be working normally.

    The audio sounds great. Only problem is that the phones pot is noisy, which maybe can be fixed with Deoxit.

    I'm really in your debt for your time, technical know-how, and kindness to share it with perfect strangers.
     
  9. hdrobien

    hdrobien Well-Known Member

    Messages:
    502
    Location:
    France
    Great !

    The phone pot is always noisy on Sony DAT. Just spray Deoxit and rotate it a couple of time.
     
  10. RMbA

    RMbA Member

    Messages:
    89
    Thanks again!
     
  11. RMbA

    RMbA Member

    Messages:
    89
    I'm not seeing more than an extremely small opening for the Deoxit. Is it necessary to do some kind of disassembly?
     

     

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  12. hdrobien

    hdrobien Well-Known Member

    Messages:
    502
    Location:
    France
    No disassembly. Just shower it.
     
  13. RMbA

    RMbA Member

    Messages:
    89
    OK—thanks.
     
  14. redjr

    redjr AK Subscriber Subscriber

    Messages:
    612
    Location:
    Danbury, CT
    SaSi,

    Thanks for such a comprehensive guide to bringing older DAT transports to life. I'm late to the original party, but see there's still activity in this thread. I have a mint condition A6 that has not been used in several years and when it was it has had very little use. A couple of mastering tapes were made - according to the original owner. When I put in a tape, I've watched it load around the head and everything looks aligned with no loose levers, linkages or loose switches. It will then attempt to go into play, but stops abruptly. It would seem the take-up spool will not rotate, and therefore the infamous CAUTION message is displayed. I've taken a look inside and removed the transport, and it is very clean with little dust to be found. All belts and pulleys are intact. I did clean - with DeOxit - 2 little pin switches on a small PCB in the lower front/side of the mechanism - based on what I earlier found on YouTube. However, it did not make a difference.

    I have not read the entire thread, but will continue to work my way through it hoping for more information that may be helpful. This is a great resource for those of us interested in bringing our DAT machines back from the dead. Suggestions?
     
  15. hdrobien

    hdrobien Well-Known Member

    Messages:
    502
    Location:
    France
    Hi

    Investigating will require dismantling skills. Are confident enough ?

    First, push the black plunger at the end of the white lever on the front of the transport. It will release the brakes.

    Then check that both spools freely rotate.
     
  16. redjr

    redjr AK Subscriber Subscriber

    Messages:
    612
    Location:
    Danbury, CT
    Yes, I can dismantle if necessary. I obviously only want to dismantle it only as far as I need to. I've had the transport out and holding it while trying to observe what happens, but when it goes into CAUTION so quickly, it's hard to determine what to check next. :) I've dismantled it a little to get at 2 pin switches, but I've not gone into the bowels of it - yet!

    I can free the spindles by pushing on the black solenoid plunger on the front left.

    Edit: I just looked again at the transport when loading and after pressing play. The capstan motor is working(or at least starts), the pinch roller engages, and then everything shuts down. I'm guessing the take-up motor, or spindle not engaging in play mode?

    Edit2: The take-up spindle is definitely not even trying to rotate, so something is amiss with it or related mechanics/circuitry. Since it doesn't even attempt to rotate that likely is throwing the error?
     
    Last edited: Mar 18, 2018

     

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  17. hdrobien

    hdrobien Well-Known Member

    Messages:
    502
    Location:
    France
    OK.

    Locate RV451 (torque pot) on the main board, memorize its present position, then try to rotate it in both direction. It will increase/decrease torque in the take up spool.

    Check if take-up spool rotates in play mode.

    Do not hesitate to post pictures of the transport. It may rise a idea.
     
    Last edited: Mar 18, 2018
  18. redjr

    redjr AK Subscriber Subscriber

    Messages:
    612
    Location:
    Danbury, CT
    I rotated the pot 1/4 turn in either direction and recycled the play button. No movement of the take-up reel at all. Almost like it's disconnected from everything.

    Is there a dedicated take-up motor, or is it shared with other functions?
     
  19. hdrobien

    hdrobien Well-Known Member

    Messages:
    502
    Location:
    France
    Ok

    The same motor drives both spools. A kind of swinging gear will transmit rotation.

    1. If you insert a cassette without hitting the play button (just "open/close"), does it load the tape and display the ABS time, without the caution message ?

    2. When you hit play, can you see the supply spool rotating ?
     
  20. redjr

    redjr AK Subscriber Subscriber

    Messages:
    612
    Location:
    Danbury, CT
    1. Yes, displays ABS time, but immediately goes to CAUTION after about 2 secs.
    2. Yes, the supply spool starts to rotate.
     

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