yamaha NS-200Ma

Discussion in 'Speakers' started by memustbefree, Oct 19, 2013.

  1. memustbefree

    memustbefree New Member

    Messages:
    47
    Location:
    Niseko Japan
    Found this Yamis in an old warehouse we cleaned out at work today, everything was going to the dump but not this ones they got a ride home with me. And now iam really glad i saved them!
    They sound GOOD but one cabinet are badly water damaged, anyone have fixed a cabinet this damage?
    what would be the best way to clean up the aluminium around the woofer?
     

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    Last edited: Oct 19, 2013
  2. memustbefree

    memustbefree New Member

    Messages:
    47
    Location:
    Niseko Japan
    I toke out the drivers and clean them up but its just mold every were in the cabinet so i think i will build new ones.
    but my Q are should i just copy the original or go with something different?
    I have Australian ash to build a par of the originals, hard wood vs particle board vs MDF?
     
  3. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

    Messages:
    2,292
    Location:
    Munich, Germany
    As far as cleaning the alu frames, iirc from my etching days tap water and rainwater is usually slightly acidic, say ph 5.5 to 6 or so. We used to clean up aluminum with a slightly caustic solution, say ph 8 or so. ph 7 is neutral.

    So you could try putting a small amount of baking soda in some water, and use moist scotch-brite to polish them. Dip your scotch brite and wring out the water till it's just moist. You can get scotch-brite in various grits and can polish alu quite fine with it. Take your time and wipe clean with a cloth from time to time to check how it looks.

    Depending on how deep the corrosion went they will probably still be pitted but you can at least remove the scale that way. Dry them completely and if you want to protect them from further damage carefully brush them with clear lacquer. Make sure they are 100% dry first.

    The area where those steel mounting screws are/were will probably be the worst because of dissimilar metal corrosion. The screws themselves rusting accelerates things. SS screws would be a better choice.
     
  4. mech986

    mech986 Text ↓ optional La Habra, Calif. Posts:>17,000 Subscriber

    Messages:
    17,936
    Location:
    La Habra, California, USA
    Any update after a couple of years on these Yamaha speakers?
     
  5. memustbefree

    memustbefree New Member

    Messages:
    47
    Location:
    Niseko Japan
    Yeah, I play them everyday paired with sansui Au-a607L extra and it sound are very good highs are rely detailed, they lack a bit of bass but i think its just
    because the woofer edges are deformed and need to be replaced
     
  6. tmad40blue

    tmad40blue "I can hear forever!"

    Messages:
    2,311
    Location:
    Ann Arbor, MI
    @memustbefree

    DO NOT play speakers with deteriorated woofer surrounds!!! You are setting yourself up for disaster, that is a one-way ticket to permanently ruining the woofers.

    You need to replace the foam surrounds (called "refoaming") of the woofers before you listen to them again. There are likely hundreds of threads all over AudioKarma that can help you out with the process of refoaming. I saw from your profile that you're in Japan - I don't know about Japanese foam surround sellers, but I'm sure you'll find some, as it is well-known that there is a wonderful hi-fi market in Japan.
     
    mech986 likes this.
  7. fishondwan

    fishondwan AK Subscriber Subscriber

    Messages:
    747
    Location:
    S.W. Michigan
    Pull those Woofers out, turn them 180 degrees and put them back in :thumbsup:

    Are the surrounds foam or are they fabric ?
    Nice save on those ! I've been listening to NS-690's and NS-670's lately and I think they both sound phenomenal. I'm sure those share A lot of the same sound qualities
     
  8. memustbefree

    memustbefree New Member

    Messages:
    47
    Location:
    Niseko Japan
    I will re foaming them when i have time, have the kit on the shelf. 180 for now maybe, its fabric edges on the woofers and kind of hanging down a bit if that make sens??
     

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