Installation of a kick back system.
During manufacturing most pinball machines had some extra "gadgets" who, at the end , because of production costs ,where omitted. If there is one machine on wich a lot was ,afther some prototypes, left off, well it is Scared Stiff.
The list of things that where no longer on the machine is, no " glow in the dark" bones , no boney flippers, no dancing boogie men, no eyeball shooter , no longer lighthing eyes on the deadhead pile, and no kick back at the left outlane. All these "gadgets" are available on the WWW at different sites except the kick back feature. The main reason is that the software to command the kickback is lost, several pinball-fans did look for it but never found it anywhere. Also the reason why the kick back was not installed is that there where no more solenoid transistors on the board available! Instead a work around solution was adapted using the soft ware. When the lamp at the left outlane ( SPELL) is on, and the ball drains that way, a new ball is served and shot into the playfield by the auto-plunger. The consquence of that is by re- installing the kick-back there will be a two ball multiball if the kick back is working. The ball that drains will be brought back on the playfield by the kick back, and at the same time a new ball is launched on the playfield by the auto shooter.
I found the extra two ball multiball a nice feature ,and worked out a solution to re-install the kick-back on my Scared Stiff.
It is not to difficult and the average handy-man can certainly realise this mod.
How and what.
The first thing we need is the kick-back coil from an old machine or a new one..
The one i used was and old one , with burned coil. Of course the coil was replaced!
A second difficulty ! The outlane is not at all suited to guide a ball back into the palyfield . Posts at the entrance of the outlane prevent that a ball is kicked back. We need to change some things here , to create a smoot lane that is suited to bring the ball back on the playfield. There are three posts at the entrance of the outlane , we remove two of these the first is a movable post the second is a fixed post and from the one nearest to the three ( SPELL) targets we remove the rubber sleeve.. Afther that we install a small flexible plastik strip going from the kick back to the post with rubber sleeve removed. Some photo's will clear that out.
These are the two posts that where removed the sleeve comes from the post next to the targets.
Next photo is the plastik strip used to create a smoot way out of the outlane.
Dimensions are 1,1 inch hight and 9 inch long . A smal amount of the right corner is cutted away , it fits nicely in the post that has his rubber removed ( see photos)
The plastik strip is resting against the post .
The plastic strip runs till the kick back, use two small screws to fix it agains the wooden side rail.
The kick back hole is already present , nothing to do here!
How things are connected?
Let us analyse the simple schematic.
Starting with the kick back coil at the left. the coil is connected to an extra driver transistor TIP102 , When a signal arrives at the base of this transistor the coil will fire. Do not forget to install a diode on the coil, if not the transistor will go bad. The + arriving at the coil is connected at the +lead of a slingshot coil. ( the side of the slingshot that has two wires) . The second item on the small board is a 5 volt relay. Use a small TTL relay of any brand , you will find these at every electronic shop. Contacts have to handle only a few milliamps. This relay is connected at the " SPELL" lamp situated at the left outlane. Connect the two wires as showed in the drawing , one at the non banded side of the diode at the "spell" lamp and one at the other connection at the lamp socket. The result is , when the "spell" lamp is "on" the relay is activated. parallel on the relaycoil is a electronic condensator and the command passes trought a diode. This is because the "spell "lamp is in the lamp matrix and when "on" is not fed with a continous DC voltage but by a train of pulses( giving us the impression its continously "on") To have a steady closed relay , we added the condensator and the diode. When the relay is closed , ( SPELL "on") the transistor can receive +5 at his base, and the coil will fire, this happens only when the ball will pass on a run-over switch in the outlane.
Here a vieuw of the little board with the 7 parts we need to command the kick back coil .
The small 5 volt relay.
The little board mounted under the palyfield near the left flipper , close to the kickback and outlane switch.
We need a extra outlane switch to command the kickback transistor. This because the regular outlane switch is used in the switch matrix and is needed to put off the spell lamp.
Use a micro switch from an old coin switch. The two photo shows how the wire of the coin switch is shortened and bended.
The switch is mouted in a way that when the "regular" outlane switch is activated by the ball the extra switch is activated to, very easy to realise. With two wood screws the extra switch is fixed at the underside of the playfield.
The extra switch side by side with the regular outlane switch .Connect his two 'normally open' contacts at the small board.
It will be needed to bring the +5 volts and ground from the pinball head to the small board .As there is nowhere +5 volt under the playfield.