Tascam 688 capstan motor reolacement

Discussion in 'TASCAM DIY Repairs and Mods' started by Steve Summers, Apr 28, 2021.

  1. Steve Summers

    Steve Summers New Member

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    Hi - I just got a new capstan motor for my 688, but all 4 of the leads broke off of the old motor before I could document the order in which they were connected. Does anyone have a picture of the proper placement, or a video?

    thanks,

    steve
  2. keef

    keef New Member

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    Hi,
    I am not sure how to link to the post but if you search for " 644 repair " you should find a
    photograph of the wires for a similar machine to your 688.

    keef
  3. Steve Summers

    Steve Summers New Member

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    Thank you, Keef. I’ll look for it.

    Cheers,

    Steve
  4. SkywaveTDR

    SkywaveTDR Well-Known Member

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    Two wires will be power and ground- not hard to figure out from a measurement and the other two would be coming from the pitch control area of the board. You can use a DVM on diode test to see where they end up.
  5. Steve Summers

    Steve Summers New Member

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    Thank you, Skywave. It turned out I had taken photos. The motor was a direct replacement, supposedly brand new, although that seems unlikely to me. The deck works now but I have to use the varispeed and turn it way up to make the tape play at the proper speed. Anyway. It does work. Any recommendations for a cleaner for the pots and faders other than Deoxit?

    Thanks- Steve
  6. SkywaveTDR

    SkywaveTDR Well-Known Member

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    The new motor once put in needs to be calibrated with pitch control in center using a MXT111 tape. You could use a MTT111 but set for 6000Hz rather than 3KHz as it is double speed.
    Can't measure wow and flutter that way though.
    There are no decks that you just put a motor in and it is at correct speed- they all need calibration at the start of setting up the deck and speed is the first thing.
  7. Steve Summers

    Steve Summers New Member

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    Thanks very much, Skywave. You’re very kind.
  8. SkywaveTDR

    SkywaveTDR Well-Known Member

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    I use Deoxit on switches due to contacts. The Pots and fader should have Fader Lub sprayed into them but most importantly is to cover your unit at night with a towel or plastic sheet. The amount of dust and dirt which come together as dust puppies in your equipment are very good as isolating contacts as in between the carbon substrate and a finger contact. This is why your fader are intermittent or noisy. The yellow tube Deoxit I will never buy as a lot of it goes all over the bench and floor that you are paying for- the yellow tube idea was that of some idiot. Yet they have never corrected this stupidity. It used to a good company to get products from.
    Parts Express sells contact cleaner cans larger and cheaper than Deoxit. I bought some of those and they work well for cleaning things out. So I hope this answers your cleaning question. We Technician discuss the things like this when we meet. Most guys I know are pissed at Deoxit yellow tube cans.
  9. Steve Summers

    Steve Summers New Member

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    Thanks again for a detailed and thoughtful reply. I appreciate you generously sharing your knowledge. Do you know of a source for the Teac test tape? I’ve looked online without much luck.

    Thanks again. Steve
  10. SkywaveTDR

    SkywaveTDR Well-Known Member

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    Now days Teac does not sell them but some guys make fake one on good deck that will get you very close. I made some different one in my shop for my own use. There was a guy who sold a speed tape for about $6.00 on E bay. Genn Lab in new Zealand is not the only producers of real cassette test tapes and they are not cheap.
    https://www.gennlab.com/teac_cass.html
  11. Steve Summers

    Steve Summers New Member

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    Got it. Thanks.
  12. SkywaveTDR

    SkywaveTDR Well-Known Member

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    Apparently Genn Lab is making supposed Nakamichi tapes that are noticed to be wrong but they don't like to talk about correction. This may lead me to not recommend them for a source of tape as people that are never wrong usually are you find out.
  13. Steve Summers

    Steve Summers New Member

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    Thanks for the information, Skywave. I really appreciate it.