Star Tech Journal

•
ST AR*TECH Journal
WILLIAMS SYSTEM
11 COIL
December 1992
PLUNGER PROBLEMS
Kerry Messana
Betson Advance
Syracuse, New Yark
SYMPTOMS
Can't seem to get enough power
out of the upper left ramp
diverter arms on Williams' pin F-
14. (These are similar to the
black plastic diverters used in
High Speed Listed as special
solenoids.) The unloaded/
loaded voltages to these coils
are 33V /24V. They will pull in if
the plunger is held-in partway.
Grounding the collector tabs on
the drivers fires the coils which
are AL-26-1500-02. Every-
thing seems to be reasonable.
SOLUTION
If you hold the plunger in par-
tially and it works properly then
here is the fix: Make the arma-
ture rest further into the coil in
its de-energized state. There is
a way to do this by shimming.
You will also see this problem on
High Speed on its diverter and
on Pinbot on the drop target
reset coil. The bottom line is
that the armature is not far
enough into the coil for the mag-
netism to "grab" it properly.
T RIGGERir-G
As far as special solenoids go
(on System 11that is), they can
be triggered in one of two ways.
One is via a direct switch input,
the other is via CPU control.
Both require the. EN not signal
to be low (flipper relay enabled)
to make them work. They are
usually used on slingshots and
jet bumpers but can be used in
other areas as well. Most early
System 11 games use the di-
rect switch inputs to operate
them, the later ones use
switches located in the switch
matrix to have the CPU read
them and then activate them
through the CPU side. The lat-
ter is the pref erred method
because the CPU can actually
control how many times the coil
is pulsed within a given amount
of time preventing coil and/or
circuitry burnup. On the direct
switch inputs, if you hold the
switch closed it holds the coil
energized which will of course
burn the coil and eventually the
circuitry with it.
All the games use the CPU con-
trolled side during coil self
testing and ball search mode
but the first pinball to use the
CPU side for regular coil activi-
ties was Cyclone. After Cy-
clone some used this method
and others used the traditional
direct switches. Toward the
end of System 11most if not all
used the CPU controlled type.
IDENTlFICA TION
The way to tell which system a
particular pin uses is to look at
J18 on the CPU board. If there is
nothing plugged into it then it
uses CPU controlled speci~
solenoids. If there is a plug - -
then it is switched directly.
The CPU controlled side of the
special solenoids is controlled
by various PIA's (CA2/CB2 set
to be outputs), these signals
are buffered through a 7407
open collector buffer and then
feed the 7402's to turn on the
transistor(s). You can find the
7 407 on sheet 2 of 4 on any
System 11 schematic -it is in
the top/ center of the page. The
outputs of the 7 407 go to the
inputs of the 7402's and are
also connected to the direct
switch inputs ( wire or'ed). You~,
can find this on sheet 1 of 4 in
the top right section. The
7407's outputs are designated
as A through F.