Machines and Accessories No. 01-03


Date: March 30, 2001

Subject:  Cassette Book Machine (CBM) Battery Care


This __Machines & Accessories__ is a reissue of #97-03,
issued June 13, 1997.

Proper battery care of NLS audio playback machines can
enhance machine performance and increase patron
satisfaction.  Overcharge and deep discharge
reduce the service life of batteries.  The C-1 has no
circuitry to automatically limit either overcharge or deep
discharge, but these conditions can be controlled manually.
For manual control, leave the idle unit connected to a wall
outlet for about fourteen hours to charge it, then use it
for about six hours while disconnected.  Repeat this
cycle to continue extending battery life.  While this
procedure is desirable, it is both inconvenient and
unexpected in a consumer appliance.  To ease patron concern
and inconvenience while accepting a small decrease in
performance, the CBM may be left continuously connected to a
wall outlet.  Under no circumstances should the
C-1 run without a battery installed.  Running without a
battery causes a reduction in sound quality, a slowing of
fast-forward/rewind, and increased stress on internal
components.

Although new CBMs are shipped from the factory with a fully
charged battery, self-discharge occurs within about thirty
days.  This discharge could happen during transit and
temporary storage at the machine-lending agency (MLA).  NLS
recommends that MLAs charge and test machines to ensure only
CBMs with fully charged batteries are shipped.  Patrons will
then be able to play the instruction tape without assistance
and without having to read any printed or braille enclosure.

MLAs are reminded that the factory-installed battery must
remain with CBMs that are under warranty.

For further information contact:

John Cookson
Head
Engineering Section