From: ung@felix.filenet.com (Bill Ung)
Newsgroups: rec.games.pinball
Subject: Re: What are Solid State Flippers
Date: 1 Oct 92 19:59:31 GMT
Reply-To: ung@fritz.filenet.com (Bill Ung)
Organization: FileNet Corp., Costa Mesa, CA

In article <1992Sep30.204800.27328@kong.gsfc.nasa.gov> mstephens.520@postman.gsfc.nasa.gov (mark stephens) writes:
|I can't stand it any more!  There's lots of msgs with hints on what solid
|state flippers are.  I understand the way the old ones work, with two
|solenoids (well, I mostly understand).  But how are SS ones different?
|
|       mark

Rather than re-invent the wheel, I'll borrow someone else's work...

From Brian Casper <bcasper@eos.ncsu.edu>:

Flipper motors are actually solenoids that are made of two windings of coil
with the primary winding (strong pull-in stage) being about 1/3 of the coils
wire, and the other (hold-up stage) being the other 2/3 of the coil wire.
The thing is wired somewhat like this:

  ()()()()()()()()()  <--- Coil windings
  |     |          |
  |     |          |
  |     +----EOS---+   <-- End Of Stroke Switch   (Normally closed)
  |                |
  |                |
  +--PS------FS----+   <-- Power Supply  &  Flipper Switch


When the flipper is in the down positin, the EOS is closed and the upper 2/3
of the coil is shorted.  This allows all of the current to flow through the
smaller 1/3 of the windings which in turn produces a relatively strong field
and the steel plunger is retracted.  At the end of the stroke when the flipper
is in the upper position, the EOS switch is pushed open.  The current is then
allowed to flow throught the entire coil.  Since no extra current is supplied
when this happens, the field becomes relatively weak, but the current is
dissapated through more wire.  As a result, less heat is generated within the
windings.  The reduced field is still strong enough to hold the flipper in
its upright position.

The trouble starts when the EOS switch is maladjusted or broken.  If the switch
does not fully close, the flippers will be weak since the strong field is never
generated.  If the switch stays closed, the small portion of the coil will
always carry the full load.  If the flipper switch is held in for an extended
period of time, the heat generated will be enough to bake the coating off of
the coil wire.  Then the coil shorts out and meltdown occurs...  If you've
never seen the inside of a fried coil, trust me - it's not a pretty sight ;-)

----------------------------------------------------------------------------

That takes care of what the old flippers are like, now for an explantion
of solid-state...

From Bennett Broder <ben@monmouth.edu>

Williams SS flippers also have a Data East style timer to cut power to
the main coil after a given amount of time elapses.  This protects
the flipper coil and also keeps the game working (and earning $$$) if
EOS switch fails.  (The failed EOS switch would be reported in the
diagnostics, and the affected flipper might lose its "classic" Williams
feel, but otherwise should operate fine)

Other differences are that the computer grade EOS switches on the new
machines are normally open, while the heavy duty switches on the older
machines were normally closed, and that the contacts on the new switches
shouldn't be filed or sanded clean as they could be on the older ones.

----------------------------------------------------------------------------

Now, other things I've heard are that the older games (like my HIGH SPEED,
1986) have the full 50 volts used to power the coil going through that
EOS switch.  Lots of arcing and worn out contacts.  Later games (don't
know which ones) have changed that to only having a standard 5 volts
going through the EOS switch and having THAT electronically switch the
50 volt line to the flippers.  Made for longer lasting contacts/flippers.

Hope this helps, Mark.

Bill Ung
  ung@filenet.com