Stephen Small requested information about the rewind function of
his Ampico B.  The description given of your problem is too brief
for complete analysis.  If the lockup of the spool is only momentary,
and the rewind function resumes with no action on your part, the
machine is operating correctly.  The Ampico B on rewind tightens
the roll periodically by bringing the take up spool to a dead stop.
This is normal.

If the lockup occurs at all times, several adjustments might be needed.
The cam and pallet mounted on the roll motor control the rewind brake.
The brake is active when the pallet closes.

The obvious fix is to inform the person who restored the mechanism,
and let him/her correct the problem.  At least they should be able to
talk you through the fix.

Bob Taylor