Star Tech Journal

Pinball Plastics &
Teniperature
Willianis Diner
Playfield Mod
Peter Gustafson
Data East Pinball
Melrose Park, Illinois
Jeffrey D. Best
Jollytime
West Bend, Wisconsin
SUBJECT
SUBJECT
In hot sunny climates, where pinball plastics
have a tendency to melt when exposed to the sun
for long periods of time, it was suggested to use
polycarbonate plastic instead of the present type
of plastic to combat this problem.
Here is another quick and dirty solution to a new
problem. Diner Pinball (Williams) has a drop hole
to a lower track and solenoid to return the ball
into play-or lock it and return it to play later for
multi ball play.
DECO MATERIALS
PROBLEM
The material we use to make our plastic ramps
is called PETG (Co-Polyester Glycol Modified
Polyethylene Terephthalate). And unless they
have changed in the last game or two, our
competitors use the same material in their
vacuum formed ramps.
The problem is in the return track. It has too
much clearance between the lower rails and the
playfi.eld. This allows the ball to sometimes spin
out of the rails and land in the bottom of the
game.
Result Game is down until the ball is recovered.
POLYESTER
PETG is formed at 216-265 degrees Fahrenheit.
Heat distortion may occur at 140 degrees
Fahrenheit. The material can also be damaged
by long term exposure to ultraviolet rays.
POLYCARBONATE
Lexan Polycarbonate distorts at 190 degrees.
While it tolerates heat better, Lexan does have 3
disadvantages:
1) Its forming temperature is considerably
higher then PETG.
2) It requires an 8 hour pre-bake operation at
180 degrees to remove trapped moisture prior to
vacuum forming. (PETG requires only 4 hours of
pre-bake and at a much lower temperature).
3) Most importantly, Lexan costs lots more both
in material costs and in manufacturing costs.
NoTE
My advise to anyone that operates in the south
and southwest is to put a piece of cardboard
under the glass before taking a game into the
sun for transporting.
SOLUTION
The solution is simple, keep the ball in the track.
A "shield" made from thin, flexible plastic (such
as the wall of a spray bottle, bleach bottle, etc.)
is formed over the track (play field inverted) and
screwed in place with six #8 x 1/2" sheet metal
screws. Works well and is almost free to install.
Willianis Pinball
Power Supply
Ed Romasko
Champions Amusement Centers
Philadelphia, Pennsylvania
PROBLEM
Game keeps cutting out; checked all voltages:
+5Vdc was okay, but + 12Vdc and -12Vdc were
low, approximately +9.9Vdc and -9.9Vdc re-
spectively.
CAUSE
Bad power transistor: 2N6057 type. Replace and
verify operation.