Tape is stuck

Here is another solution I found:

If your carriage is not attempting to pop up at all but is stuck in the
camera and will not move, this post WON'T HELP YOU. If you're like me,
however, and have a carriage that tries to eject but can't complete the
cycle, this may help you. First familiarize yourself with the tape
carriage. Disconnect the battery and the power cord. Turn the unit over
so that the bottom faces up, and use the eject button to open the door.
Examine the tape carriage on either end, and you'll notice a couple of
springs which keep tension on the outside section of the carriage so
that it will pop out when the catch is released. The spring closest to
the front of the unit (the lense) is the one which also operates the
catch for the pop-out mechanism. If you will put pressure just under
the top of this spring when the carriage mechanism is at the apex of
its eject cycle (and before it reloads itself because it cannot eject
the tape), then the carriage catch will release and pop out, exposing
the tape for removal. If the unit has "eaten" the tape (i.e., the
transport mechanism has it pinched or wrapped or both, then when you
release this catch on the carriage the tape will be pulled, crinkled,
and could be cut or broken. If this tape is full of important memories,
you might let the tech get it out himself. Also, more damage to the
tape will occur if, after getting the carriage to pop out, you try to
pull the tape out of the carriage after it has opened, if in fact the
transport mechanism is still hanging onto it. Now close the tape door
and turn the unit off. Plug the unit in or connect the battery, turn it
back on, turn it over (bottom's up) and open the tape door. Once the
tape carriage reaches the apex of its eject cycle, put pressure on the
top of the spring (the spring end closest to the physical bottom of the
unit, not the "spatial" bottom since the unit is upside down). You
should feel the carriage catch slip out of its latching mechanism and
the door should pop out. If either of these springs are missing or
broken, the carriage will probably not eject even after releasing the
catch. If the carriage is not sliding downward (or when the unit is
upside down, upward) from the bottom of the unit in an attempt to
eject, then the procedure for extracting the tape is much more involved
and requires dissasembly of the unit in order to get it out.

Here is another solution I found:

If your carriage is not attempting to pop up at all but is stuck in the camera and will not move, this post WON'T HELP YOU. If you're like me, however, and have a carriage that tries to eject but can't complete the cycle, this may help you. First familiarize yourself with the tape carriage. Disconnect the battery and the power cord. Turn the unit over so that the bottom faces up, and use the eject button to open the door. Examine the tape carriage on either end, and you'll notice a couple of springs which keep tension on the outside section of the carriage so that it will pop out when the catch is released. The spring closest to the front of the unit (the lense) is the one which also operates the catch for the pop-out mechanism. If you will put pressure just under the top of this spring when the carriage mechanism is at the apex of its eject cycle (and before it reloads itself because it cannot eject the tape), then the carriage catch will release and pop out, exposing the tape for removal. If the unit has "eaten" the tape (i.e., the transport mechanism has it pinched or wrapped or both, then when you release this catch on the carriage the tape will be pulled, crinkled, and could be cut or broken. If this tape is full of important memories, you might let the tech get it out himself. Also, more damage to the tape will occur if, after getting the carriage to pop out, you try to pull the tape out of the carriage after it has opened, if in fact the transport mechanism is still hanging onto it. Now close the tape door and turn the unit off. Plug the unit in or connect the battery, turn it back on, turn it over (bottom's up) and open the tape door. Once the tape carriage reaches the apex of its eject cycle, put pressure on the top of the spring (the spring end closest to the physical bottom of the unit, not the "spatial" bottom since the unit is upside down). You should feel the carriage catch slip out of its latching mechanism and the door should pop out. If either of these springs are missing or broken, the carriage will probably not eject even after releasing the catch. If the carriage is not sliding downward (or when the unit is upside down, upward) from the bottom of the unit in an attempt to eject, then the procedure for extracting the tape is much more involved and requires dissasembly of the unit in order to get it out.