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Can someone help me do a minor fix to my stereo?

Discussion in 'Electronic Repair' started by Greg Bailey, Mar 6, 2008.

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  1. Greg Bailey

    Greg Bailey Guest

    I have a four-year old Aiwa/Sony shelf stereo. I am having a problem with
    it. With some CDs, particularly some that seem a bit lighter in weight, I am
    getting a horrible whining noise and sometimes the thing even starts
    skipping.

    I started to get rid of the thing, but after shopping around, I discovered
    that it's superior to any other shelf system I checked out, plus I
    determined that I simply don't have the space, resources, etc., right now to
    assemble a component setup in my bedroom, which is where this stereo is. So
    I decided to keep the thing and try to get it fixed.

    I know, from a Sony Technical Bulletin, that this issue is caused by an
    oscillation problem with the specific Sony optical pickup (KSS-240A) that's
    installed on the thing, that causes a mechanical resonance issue with the
    discs as they play. I know, from a Sony Technical Bulletin, that the fix for
    this is to add a brass weight (part No. 4-962-979-01) to the pickup, and a
    felt washer (part No. 4-986-769-01) to the surface of the clamper that
    touches the disc. The screw (part No. 7-685-134-19) that adds the weight to
    the pickup replaces the screw that holds the PC board with the pots to the
    laser.
    I have these parts in hand from Sony, ready to install. I have spent the
    morning trying to find someone to install them, since I've never done this
    kind of thing before. I've discovered that no one works on stereos anymore.
    I'm not surprised of this, because I'm sure they're considered kind of
    disposable. But I don't want to dispose of this one when all that needs to
    be done is a piece of brass screwed in somewhere and a piece of felt stuck
    somewhere.

    Let me take that back, there is one person in my town who will do such work,
    and he's very good and quite cheap. The only problem is I might get the
    stereo back around Inauguration Day ... of 2013.

    So, is there anyone out there who could clue me in on just how big a deal
    what I have described is to execute, whether it's something a
    do-it-yourselfer should even attempt or should I still beat the bushes
    trying to find somebody to do it. And if it is something simple that I could
    do, could you give me "See Spot Run" simple, hand-holding directions,
    starting from the moment I take the first screw out of the thing, as to how
    I do it, what exactly I need to look for, what do I need to be careful of,
    etc., because I really don't want to trash the thing trying to fix it.
    Because I really have no clue whatsoever where or what these specific things
    (clamper, PC board with pots, pickup, laser, etc.) are or look like.

    Thanks in advance for any help.
     
  2. James Sweet

    James Sweet Guest

    Did it come with any instructions? If you have a screwdriver you ought to be
    able to fix this yourself, it should only take a few minutes. If you're
    really that much of a newbie, I suggest finding someone local to help, don't
    you have any engineer or handyman friends or neighbors? It would be very
    hard for someone to give you such detailed instructions over the internet
    without being familiar with that particular unit.
     
  3. Greg Bailey

    Greg Bailey Guest

    No, all I got was a piece of felt, a brass weight and a screw. I've been
    trying to find a diagram of that particular pickup online, to use as
    reference, without any success so far.
     
  4. Dave

    Dave Guest

    Have a look here:

    http://electronics.howstuffworks.com/cd4.htm

    The optical pickup is the lens you see which is on a sled which moves
    horizontally as the CD spins. As in the picture in the above link, the
    pickup head is often attached to a small circuit board with some
    focus/tracking components. You can actually see a screw in the picture,
    although yours might be somewhat different it shouldn't be rocket science to
    open it up, remove a screw holding the laser assembly to the attached PCB,
    and install the brass one. Be careful not to move any of the pots (they'll
    probably have a drop of adhesive keeping them from moving) as that will mess
    up your focus/tracking/alignment. As far as the hunk of felt, I assume it's
    got sticky backing on it on one side? When you open up the player, there
    is, to use Sony's term, a "clamper" which grabs the CD, allowing the spindle
    motor to spin it. You need whatever is attached to the spindle motor
    (called "disks drive" in the picture) to have friction on the disc, so I'd
    think the felt washer would go on the other side (which would be the top),
    but it should be obvious where the washer will fit once you get things
    opened up.

    Don't worry about this one: it's not at all a technical repair and if you
    are careful, it'd be pretty hard to break anything.

    Dave
     
  5. Greg Bailey

    Greg Bailey Guest

    THANK YOU!!! This is exactly what I needed. And it looks like I'm going to
    be the one to do it, no local techs would fool with it.
     
  6. Guest

    Here's a picture of the KSS-240A pickup:
    http://www.studiosoundelectronics.com/kss240a.jpg
    You can see the screw to the left of the label.

    The other thing to be careful of is ESD (Electrostatic Discharge). If
    you
    don't have an antistatic wrist strap, at least take some common sense
    precautions: minimize plastic and fabrics (carpet, wool or acrylic
    sweater)
    in the vicinity of your repair, pick a more humid day or area to do
    the
    repair, and touch the metal chassis of the stereo system (if it has
    one)
    before approaching the pickup or other electronic devices with your
    hands.

    TM
     
  7. Greg Bailey

    Greg Bailey Guest

    Gotcha ... I've done work inside my computer before so I know about avoiding
    ESD.
     
  8. mm

    mm Guest

    Hilarious. This is what I used to use on my record player when the
    tone-arm skipped.

    If you are inclined to email me
    for some reason, remove NOPSAM :)
     
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