Greetings, and thanks right away for your interest and potential help
with the following:
We have a set of approximately 30 SKC Brand, GX and LX model, Type I
cassette tapes on hand to transfer. They are 60 minute tapes.
The original field recordist is from New Zealand, where these tapes were
A number of the tapes start squealing after five to twenty minutes of
play, and this happens on at least three different Nak CR-7A machines
The squeal is a rather constant tone in amplitude and frequency (2 kHz
or so is a guess). The decks have even stopped themselves in some
instances. The squealing in some instances has stopped when I stopped
the deck, remove the cassette from it for inspection, replaced, and
played again. But, only to likely start again a little later.
Tapes have been fast forwarded and rewound before being played. I
believe the squealing has happened when the tape is packed even better,
e.g. after a play on one side (which didn't have noticeable issues).
But play of the first side may not have been monitored very closely by
personnel, so don't give that all too much weight.
I've occasionally seen conical wrapping at the outside of the pack (the
outside 1/8" or so, thinking radially).
I've transferred some of these tapes to new Maxell shells, removed
friction sheets in the original shells, removed pressure pads in the
original shells, loosened case screws in both shells, threaded tape on
the inside (instead of outside) of the posts near the cassette shell
rollers in the Maxell shell.
I checked W/F specs on all machines. They are okay, or just out of
spec, which does not concern me here (yet).
The best I've done is maybe reduced the amplitude and regularity of the
squealing with playback of one tape I recall, but I haven't gotten rid
My current belief is that we have lubricant issues, and I'm off to
read/reread everything I can find in old emails from Richard Hess, Marie
O'Connell, Steve Smolian that I saved for future reference, like the
ones I've forwarded below.
I'd be happy to hear anything else someone may have to offer. Even moral
support! ;-D Thanks again for your interest.
Cornell Lab of Ornithology
159 Sapsucker Woods Road
Ithaca, NY 14850
[log in to unmask]
To interpret and conserve the Earth's biological diversity through research, education, and citizen science focused on birds.