It's very hard to know what happened.  Especially if the power cord was
extended, acting as an antenna, it's conceivable that the player suffered
from electrostatic discharge.  There are 20 chips, most of them CMOS, on the
player's 2 by 3 inch circuit board, and great pains were taken to make the
design power-efficient.  Players are tested for ESD during qualification,
but we don't know what the field strength was at the instant of the
lightning strike.

There is a gas gauge chip in the player which monitors the ambient
temperature, the battery voltage, and the amount of amper-hours which have
been put into and taken out of the battery pack.  In addition, there is a
thermistor inside the battery pack which is deliberately set up to
temporarily halt charging when the pack temperature gets above about 55
degrees C.  Typically when this happens, if you wait 45 minutes or so, the
battery will cool down and charging will resume for a few minutes.  But the
player will not over-charge the battery pack; it only goes through this
cycle a couple of times.

Of the 400,000 players which have been manufactured, only a few hundred have
had to go back to Shinano-Kenshi for warranty repair.  The failure rate is
astoundingly low, so far.

More in another message.
73,
Lloyd Rasmussen, W3IUU, Wheaton, Maryland
Home:  http://lras.home.sprynet.com
Work:  http://www.loc.gov/nls
 
> -----Original Message-----
> From: For blind ham radio operators [mailto:[log in to unmask]]
> On Behalf Of Harvey Heagy
> Sent: Thursday, February 16, 2012 6:02 AM
> To: [log in to unmask]
> Subject: OT question about NLS digital player
> 
> I am asking this on behalf of someone who doesn't have a computer.  They
> say
> they were reading a book on battery power with the player unplugged when
> after a clap of thunder the player said, "Battery Low."  They had several
> hours of battery power left before the thunder clap, but lost it all
> afterwards.  Then the next time they charged it up, it drained down to the
> same point when there was again no power.  Could the thunder storm or
> lightning caused this with the player unplugged, or was this purely
> coincidental?  They had the standard player which they sent back for
> another
> one after this incident.  I think the NLS digital format is the best ever
> offered by NLS, but I find this series of events very strange.  I could
> understand it if the player was plugged in, but not unplugged and on
> battery
> power.  73.
> Harvey