It's hard to diagnose, but the problem you describe could actually be
the tape skewing and possibly damaging the tape. Beware.
It sounds as if you're losing tape-to-head contact.
I'm not familiar with the 480 but http://www.naks.com tells us it was
made 1979-1982. It is a three-motor deck with a belt drive double
capstan and a pressure pad lifter. So, it sounds to me that something
is wrong with the tape path. The two capstans/pressure rollers could
be dirty, or the pressure rollers may need replacing. The belt could
also need replacing.
The pressure pad lifter pushes the cassette's own pressure pad out of
the way, saying "I can handle tape better than you--outta my way you
silly old piece of felt!" <smile>.
So with the pressure pad out of the way, the dual capstans have to
maintain the tension across the heads for proper playback. It sounds
as if you're losing this tension and with no pressure pad to push it
back, you hear the poor results.
The inbound capstan is actually providing tension holdback for the
tape and paying it out, while the outbound capstan is pulling it
through. There is a differential (I'm not sure precisely how it's
introduced) to maintain controlled tension over the heads.
This is a two-head deck, so it is more difficult to align and it
doesn't have playback azimuth adjustment so, unless you're doing that
manually, you're not getting optimum playback. There are two machines
on eBay right now (the joys of Naks.com -- it shows you the related
products on eBay currently on each page) about in the same price
range that you paid.
At 08:14 PM 7/7/2005, you wrote:
>I'm sort of an amateur archivist, mostly working on underground bands of
>the last 20 years that may have only recorded demos on cassette. I
>haven't had the money for a new deck in many years and about 6 months ago
>I found a used Nakamichi 480 model from the mid 80's. It pulled tape and
>seemed to play and record fine when I turned it up and seemed worth the
>$30. I hadn't used it in a while, but when I tried the other day I found
>something rather strange. The tape will play clearly for 20-30 seconds,
>then will start to lower in volume and have sort of a muddy sound, not
>unlike a tape left in the sun. If I hit stop and play again it sounds
>perfect again for a similar amount of time, and it seems I can do this
>over and over with the same results. Any idea what the problem is? I
>cleaned the heads when I got it and there was nothing obviously wrong to
>my very amateur eyes. My question would be is it worth the expense.
>There is a local shop that does work in Nakamichi and I'd bet it would
>cost $100 or more. Do older consumer grade Nakamichis hold up over time
>and would it be possible to get it "tuned up" to make sure the speed it
>correct, heads OK, etc? If I were to put $120-150 into it would it
>likely be as good or better as anything I could buy new in the same price
>range? I have piles of cassettes that I can't really do much with until
>I have a deck that works properly, but I'm not in the market for a new
>high end deck. Any ideas on what other decks I might consider if this
>one is beyond hope would be much obliged. Thanks. Randy
Richard L. Hess email: [log in to unmask]
Media web: http://www.richardhess.com/tape/
Aurora, Ontario, Canada (905) 713 6733 1-877-TAPE-FIX
Detailed contact information: http://www.richardhess.com/tape/contact.htm