[GreenKeys] Adder and calculator failure mode

[John Nagle]

On 7/10/2012 3:20 PM, greenkeys-request at mailman.qth.net wrote:
> In addition to the German Lorenz (GPE "Iron-Horse" Perforator look
> alike), I am also hoping to tackle a seized up NCR adding machine. See
> attached picture.

Good adding machines and calculators are designed to jam when they
become inaccurate.  It's a checking mechanism.  There are times in
the cycle where a bail drops into a slot on a wheel, and if the wheel 
isn't in a valid discrete position, the bail won't go in.  This
jams the bail actuation mechanism and a clutch back at the motor
stops the entire machine.  Friden calculators work that way.

So if you have a jammed calculator or adder of a good make, it may
be worn out.  You can unjam it, but if it's reached end of life,
it will jam again.

				John Nagle