Play Meter

Atarl switches
now modifiable
To improve response on bumpers ,
kickers , and overall playfield action
on Atari pinballs (Atarians , Time
2000, Airborne Avenger and Middle
Earth) some of the switches (micro)
can be replaced by other manu-
facturers' switch assemblies . The
modifications are easy , requiring
only time and certain materials to be
performed.
A note on Space Riders : the ball
return kicker plunger is linked to the
kicker arm through a spring. Atari did
improve the spring ; however , if you
still have the problem , you can use a
kicker plunger and link assembly
from other manufacturers . Although
it puts more stress in the fiber , it
works as well.
The stand up switches on the side
of the captive ball targets can be
extended with a Gottlieb standard
switch blade .
Solution for those flipper game
legs with damaged leveler's base : drill
a hole so that the legs leveler moves
freely and use two hex nuts and 1/ 8
inch thick flat washers on each side of
the base .
'Kiss' marks
circuit changes
You are now the proud new
owner of a Bally Kiss pinball. You'll
find some interesting changes on this
game involving the lamp circuits .
Bally , in its infinite marketing wis-
dom , decided to tie in the lamps in
the back flash with the playfield
features . All of these additional
lamps means additional circuits and
additional power requirements .
On the rectifier board in the
transformer assembly you will notice
they've added two new T0-3's
(transistor shaped) with heat sinks .
They are rectifiers. The two of them
form a bridge providing 6.5 volts DC
to the lamp circuits. This line is fused
at 20 amps . This circuit takes the
place of the 5.4 volt , 10 amp circuit
on the older games .
Up on the side in the head , you'll
find the auxiliary lamp driver board .
Its task is controlling the lamps in the
Kiss on the glass. It shares some
signals with the main lamp driver
board, namely: data lines ADO ,
ADl , and chip select lines PDO ,
POl , PD2 , PD3 . Also lamp strobe
#2 from the MPU enables the
circuits. Add a 5 volt supply for the
logic and we 're all done. The SCR's
are 106's, just like on the main lamp
board .
TV Monitors Made Easy
A TV monitor is an electronic
device that displays a video signal on
a phosphorescent screen for viewing.
It has several parts:
(a) Power Supply- to supply
working voltages for the circuits .
(b) Picture Tube- (CRT) where the
picture is displayed ; has a "gun" in
the neck that fires a beam of
electrons toward the phosphor-coat-
ed screen . This phosphor glows
brightly when hit by electrons .
(c) High Voltage Supply -creates
the high voltage used to charge the
shell of the CRT to accelerate the
electron beam.
(d) Horizontal and Vertical Oscilla-
tors - to sweep the electron beam
back and forth , and up and down to
generate the raster . Raster is the
name for the lit-up but blank screen.
{e) Video Amp - modulates the
strength of the electron beam (makes
the little lines light or dark) as it
sweeps to generate an image .
The TV image is made · up of
several hundred lines that vary in
brightness . These lines are actually
made one at a time but this happens
so fast that the eye sees the whole
image . The screen is completely
scanned thirty times each second.
We call the image made of uniform
bright lines , "raster ."
Adjustments
The various adjustments on our
monitors function just as their
counterparts on regular TV sets .
1. Brightness- adjust before con -
trast. Adjust so that the CRT
background is as dark as possible
without diminishing the brightness of
the video display .
2. Contrast - adjust so the images
are as bright as possible against the
pre-adjusted background without
being blurred .
3. Vertical Hold - adjust only if the
picture appears to be rolling up or
down the CRT: adjust for a stable ,
centered picture .
4 . Vertical Size- (The vertical size
and vertical linearity controls are
interactive) simply adjust for desired
picture size.
5 . Vertical Linearity - adjust only
if top of picture seems compressed.
Adjust so raster lines are all evenly
spaced. May require readjustment of
vertical size control.
6. Other controls and the yoke -
don 't mess with these unless ·you've
been checked out on them .
You can 't hurt anything with these
controls, so don 't worry about doing
it wrong .
A word about safety (actually
several words) :
Most of the circuitry in a monitor
runs on thirty volts. That's about
what you would find in a pinball
machine . There are certain parts of
the monitor operating on consider-
ably higher voltage. These voltages
should be respected , not feared.
The doughnut shaped whatzit in
th e corner with the thick red wire
coming out is the source of much of
this higher voltage-it's called the
"flyback transformer ." The red wire
going up to the picture tube generally
carries several thousand volts (a
rough estimate is about 1000 volts
for each inch the picture tube is
wide) . Just keep your fingers away
from these things when the set is on
and you'll be all right .
Contrary to popular opinion, the
outside of the picture tube is not
charged-if you look inside there
you'll see that the outer coating of the
picture tube is connected to the
chassis and thus grounded .
Generally if you use only one
hand while working in the monitor
you're less likely to make a circuit of
yourself (that's the technical way of
saying "get a poke").
Calendar
November 27-29
Incomat '79 , Kongrebzentrum Wien -
Oberlaa , Vienna
January 18-20
Music Operators of Minnesota , Min -
neapolis
January 25-26
Oregon Amusement & Music Opera-
tors Association , Jantzen Beach ,
Portland
March 20-22
Amuse ment Operators Expo ., Fair-
mont Hotel , New Orleans
May 16-18
Music and Amusement Association ,
annual convention, Host Farm ,
Lancaster , Pennsylvania