Thanks for the very useful messages. In addition to the
electrostatic effects of a nearby lightning strike,  there are
also electromagnetic inductive effects. The mechanism is
relatively straight-forward. What is hard to comprehend is the
magnitude of the energy levels involved which is why really
bizarre things can and do happen.

	Lightning energy involves so many huge numbers that it is
hard to get our brains around them. Lightning strikes are
measured in the hundreds of millions of Joules. A Joule is 1
watt per second which, by definition, makes a watt-hour equal to
3.6 million Jules or 3.6 megajoules. A pretty decent lightning
strike can deliver hundreds of megajoules to Earth in a few
millionths of a second which generates a strong magnetic field
in whatever just got hit.

	Any time you pass a current through a conductor, you get
a magnetic field and anytime you take a piece of metal and sweep
it through a magnetic field, voltage magically appears in the
conductor. This is how transformers work and also how a
lightning strike might generate enough magnetism briefly to
produce currents in the circuit board of a device that is not
connected to anything.

	The magnetic field decreases according to the law of
inverse squares, but if you have enough energy to power your
house for a day suddenly unleashed 20 feet away, it isn't going
to take much to produce enough voltage to ruin an IC on a
circuit board.

	As a bit of trivia, lightning energy increases as you
get closer to the Earth's Equator. Florida reports the most and
worst lightning damage each year.

Martin McCormick WB5agz

Lloyd Rasmussen writes:
> You should get your player out of storage and test it.  It should work on 
> AC
> power, but it might not run on battery anymore.
> 
> While the player is unplugged, its NiMH battery self-discharges; a process
> that goes faster if the player is stored in a warmer place.  In addition,
> the gas gauge chip is permanently connected to the battery pack, and it,
> too, draws a small amount of current, a few microamperes.  These factors 
> add
> up.  Early instructions to libraries said that if a player was going to be
> stored for more than a few months, the battery should be disconnected.  
> For
> this nominal 7.5-volt pack, if the total voltage falls below a value like 
> 3
> volts (I don't remember the exact number right now), the gas gauge chip 
> will
> inhibit charge until the voltage goes higher than that value.  The early
> players will thus get into a state where they cannot recharge their own
> battery packs.  You will find similar advice about disconnecting the 
> battery
> for modern BrailleNotes and many other devices, for various reasons.  In 
> the
> case of the notetakers, they don't fully shut down when you flip the power
> switch to Off, and run their batteries down that way.
> 
> I saw these instructions and knew that library people were unlikely to
> follow them, and that consumers might not get their players plugged in as
> soon as they received them.  I realized that if we could put a diode and
> resistor between the 5-volt regulated bus and the positive terminal of the
> battery, we could over a period of several minutes bypass the charging
> circuit and trickle-charge the battery up to a high enough voltage that 
> the
> gas gauge chip would signal for a recharge, at any time that AC power was
> connected.
> 
> After several months of testing at NLS and at the factory, this circuit
> board modification was made.  I don't remember the exact serial numbers,
> either, but after about 24,000 advanced players and 70 or 80 thousand
> standard players, the revised circuit board is used in all production.
> Since this is surface-mount technology, partially assembled by robotic
> devices, it's not practical to add these components to an existing circuit
> board.  We advise librarians to pull the battery from the old player, put 
> it
> in a newer one which has the trickle-charge modification, allow it to 
> charge
> the battery, then put it back in the old player with a setting that tells
> the processor that a full battery has been inserted.
> 
> Very few battery packs have gone bad so far, but this behavior is part of
> the reason why library technicians may tell you that there have been some
> battery problems with the NLS player.
> 
> If anyone needs a replacement NLS player of either type, it should be easy
> to get one from your network library.
> 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 John Miller
> > Sent: Thursday, February 16, 2012 8:41 AM
> > To: [log in to unmask]
> > Subject: Re: OT question about NLS digital player
> >
> > I've had my advanced one for since they first came out, whenever that 
> is,
> > I
> > was one of the first to get it in this area and my battery was good 
> last I
> > knew, I haven't used it since I moved where I am now opting for the 
> victor
> > streme but last I checked it it was working.
> > ----- Original Message -----
> > From: "Ron Canazzi" <[log in to unmask]>
> > To: <[log in to unmask]>
> > Sent: Thursday, February 16, 2012 7:27 AM
> > Subject: Re: OT question about NLS digital player
> >
> >
> > > Hi Harvey,
> > >
> > > It might be the lightning, but I doubt it.  I had a standard digital
> > > player
> > > for less than 2 years and all of a sudden--after seldom using it in
> > > battery
> > > only mode, when I tried using it for an hour or so, I got the low
> > battery
> > > indication and the player shut down.  It still worked with the  power
> > > cord.
> > >
> > > I called the NLS regional library in Albany, NY  and they said they 
> had
> > > been
> > > having "issues with the NLS new digital players and battery life."  
> The
> > > battery--according to the built-in manual--is supposed to last about 5
> > > years.
> > >
> > > I sent the standard player back and requested and received an advanced
> > > player.  I like its additional features, but whether the battery will
> > last
> > > any longer, I can't yet say--since I've only had the machine for a 
> month
> > > now.
> > >
> > >
> > >
> ...
> 
>