Terry,  Firstly, take one Valium or other nerve calming prescription,
send the dog, wife and impressionable young children out for the day,
clear the table and take a deep breath -- then get stuck in.....

The tape cartridges are in two parts and are (a) screwed together,
or (b) clipped together with projections on one plastic part that clip
into holes in the other side, or (c) glued or ultrasonically welded
together.

These attachments may be under the label so you need to peel it off or
cut it to make sure you get them all.

Obviously assembly method (a) is easy, just undo the screws and gently
remove the top half of the case.

Method (b) requires a jeweller's screwdriver to push all the projections
clear.  I found it helpful to jam matches between the case parts to
keep each section apart whilst working on the next projection.

Method (c) requires a sharp knife or razor blade to carefully split the
case.  You may find that the welding extends to a center boss which
requires a long thin knife to separate.  If you find this added
complication, you are permitted to say "Oh, darn!" or words to that
effect.

If you have a spare cartridge perhaps you should practice on that
first.  If you only wish to record once from the cartridge don't be too
concerned about breaking off the projections etc as you can tape the
halves together later, in order to play it.

Once you have the two halves of the case free, very gently remove the
top half.  Be careful you don't accidentally lift any spindles and
rollers along with the top.

Once you have the cartridge open you will see the tape on a spool,
drawing from the center and re-spooling on the periphery.  There are
several guide rollers to feed the tape and align it with the play
heads.  There may be a one-way ratchet to stop the spool rotating
backwards.

Take note of how the tape is twisted as it unreels and make sure you
keep that orientation as you re-wind it.  You should be able to turn
the spool by hand and eventually take up the slack of the tape,
remembering that it feeds out less in length than it takes up, because
of the difference in diameters.

You don't want the tape spooled too tight as that will restrict or stop
the feed out from the center.  Once back on the spool you can
reassemble the case, being careful not to catch the tape in the parts
of the case as you fit them together.

I hope this makes sense as it has been a long time since I've had a
cartridge apart and I'm going by memory.

Now a story: Several years ago I purchased a home style (i.e., not a
car type) 8-track player and around 50 cartridges at a garage sale,
at a low price I could not resist.  When I set up my prize and
commenced playing the tapes I discovered they were ALL from the Sydney
Luna Park Haunted House amusement ride and consisted of hysterical
laughter, as in "HO, HO, ho, ho, ho, ho, HO, HO, hee, hee, HEE, HEE,
Hah, Hah, Hah,..."  Get the picture?

Each tape provided around 2 hours of "Ho's".

As my wife would say "Another fine mess you've got us into, Collie."

Colin MacKinnon (Australia)