Bob,  When looking at the Wurlitzer 165 specs in the MMD Archives that
Robbie pointed you to, keep in mind that tracker holes 1-3 and 73-75
were not used in the 165 as delivered from the factory.  Many 165
owners today have retrofitted their organs with tympani action,
however, playing off the bass drum head at one edge.

The Uniphone bells tracker hole was sometimes (maybe always) teed
by Wurlitzer on its 165's to also control the bells (chimes or metal
xylophone).  Likewise one of the other unused holes controlling an
unused register stop was teed to one of the used register stops,
though I can't today tell you which ones.

 [ Uniphone was Wurlitzer's name for the Deagan Una-Fon bells
 [ incorporated in Wurlitzer instruments.  -- Robbie

The "snare drum fortissimo" is a mystery as to how it might have been
designed to work on the larger organs (166 and up) that must have used
it.

The nickel trip hole was not used on any organ, but Ross Davis
retrofitted his 165 at Griffith Park, Los Angeles, to run a tune
indicator consisting of light bulbs opposite a placard showing the
tunes on a roll.  At Seabreeze Park, in Rochester NY, we now use the
nickel trip the same way to run an LED display mounted below the two
roll boxes of the rolls currently playing to show what tune is playing
at the moment.

Implementing that use of the nickel trip has shown that a few recut
rolls -- too many, unfortunately -- have errors in the nickel trip
punching.  Since nobody else that I know of uses that hole, the errors
have gone undetected, and now it means finding the surplus holes or
lack of holes and taping them over or punching them in.  We are getting
there, but with almost 150 style 165 rolls in the collection, it takes
time.

Matthew Caulfield