STAR*TECH JOURNAL/FEBRUARY 1984
25
GINO RONDINA
RALLY VIDEO CAR CIRCUIT OPERATION (PART 4)
By Duane Erby, Kiddie Rides USA, Davenport, IA
This is the final sequence covering the Gino
Rondina Rally Race Video Car. The schematics
show the coin-op circuit and timer, score tally
circuit, character display multiplexer/video
generator, and fuel bar graph display generator.
These circuits are Figures A through D respectively.
At the end of the article will be a symptom/remedy
chart that may be of help to you in servicing this
unit
Figure A - The coin-op circuit and timer is
relatively straightforward in design and operation.
It consists of a couple of inverters to produce the
START and START signals, an ASTABLE
multivibrator using two NANO gates that generate
G-ON and G-ON, two more inverters (N8C,
N8D) that inhibit the operation of the multivibrator
when power is first applied, and at L1 is the timer
IC itself.
The circuit at the upper left of Figure A is one
way of connecting a coin counter to the game. Here
a transistor is used to drive a 9-volt counter.
Chances are, however, your game is not employing
this circuit. If you game has a 5-volt counter, the
circuit is much less complicated than this. 5-volt
counters with counter EMF discharge diodes
connected to them were connected from the 5-volt
source to the N/O pin of the coin switch. Later
models will use a 12-volt counter and have a driver
circuit At this time the exact method is unavailble.
If you will recall from last month's article, we
discussed a circuit that causes the player's car to
change into a little man who jumps and applauds
after a successful game ( score has to be > 400
points total). The flip-flop, consisting of the
NANO gates (P7), latches to generate a LO at pin
6 (EX!) and a HI at j,in 3 (EX!) if pin I of P7
(400P) goes HI. the EX! signals enable the red
car generator circuit and the audio circuit to
generate their special effects.
The circuit ofFigure B has three basic functions.
The first is to keep a running total of the "miles"
run during the game. One mile is equal to one point
of the score. The second function is to add 10, 20,
or 50 points to the score after the appropriate
bonus marker has been crossed by the player's car.
The third function is to add the miles and bonus
points together for the total points. These three
functions ofFigure Bare displayed on the CRT by
the circuit at Figure C. The three rows of digits
displayed on the CRT (upper right corner) are
defined as follows: First Row - Miles, Second
Row - Bonus, Third Row - Total Points.
The running miles circuit consists of JI IA,
JI lB, JI IC, LIO, and M9. JI I allows the decade
counters (LIO andM9) to count at either a3 .5 or7
Hertz rate that will depend on the "gear'', or more
appropriately, the "speed" the car is moving.
Recalling the fact that the racer's car has four
speeds ( designated signals are SPEED 1, SPEED2,
SPEED3, and SPEED4). We can see how the
miles counter knows how fast to increment. The
J 11 gates allow the counters to increment at the
3.5Hz rate for SPEEDS I through 3 and at
SPEED4 the counters increment at the 7Hz rate.
Bonus points are controlled and summed by the
circuit consisting of Jl2, JI ID, J7, JS, J9, JI0,
and N9. When bonus points are detected CAR*BNS
triggers the one shot atJl2 (74123). The output of
JI l / Jl2 tells our up/down counter atJ9 (74LS193)
to load data at its inputs (pins 15, I, 10, and 9).
After this, J9 will count up at a 3. 5 Hz rate until the
output pins of J9 are all HI. During this count-up
sequence, the 74LS390 at H9 will also count up.
IC H9 will hold the actual bonus scored and will be
either 0, 10, 20, or 50. You can look at JS, J9, and
J l 0 as a timing circuit that, depending on how
many bonus points were scored, allow the dual
decade counter at H9 enough time to increment to
the actual number of bonus scored.
The last function ofF igure B is to sum the miles
to the bonus and have available for further proces-
sing the total score. Four4-bit full adders are used.
These are 7483 ICs at NIO, PIO, MIO, and Ll 1.
NIO has all the BN (BONUS) data on its input
pins. MIO has the ML(MILE) data from LIO and
M9. The output total is labeled SC (SCORE) 5
through 12.
Moving on to Figure C, we have a multiplexing
circuit with a PROM IC programmed in such a
way that will allow the PROM to output numerical
digits to the CRT display. The function of the six
multiplexer I Cs is very similar to what is known as
a dot generator. Dot generators are used in com-
puter display circuits and are what make up the
characters displayed. Since our game and com-
puters are digital and not analog, the video display
can be described as having a resolution of some
known number of picture elements (Pixel Sz.).
Looking at our dots as pixels, the multiplexers in
Figure C simply ensure that the correct pixel of
each digit are placed on the screen in such a way
(more importantly at the correct time), that you
will see digits and not just a mess of dots.
Since we are displaying three sets of digits
(miles, bonus, and total) we need three sets of
multiplexers. The miles multiplexers are M12 and
Ml3 and they are controlled by ABM (miles
control signal). The bonus multiplexers are Nl2
and Nl3 and are controlled by ABB (bonus
control signal). The total score multiplexers are at
P12 and P13 and are controlled by ABS (score
control signal). The control signals are used to
enable the multiplexer output pins.
Figure D has two major functions to perform.
The first is to generate FUELVIDEO and FUEL
= 0 signals. The second is to generate a signal to be
sent to the audio circuit which will let the player
know fuel is low. This signal is labeled AUDIO
RE SERVA. AUDIO RE SERVA when active is a
pulse train at a 3.5Hz rate that controls an audio
oscillator and is heard by the player as a series of
beeps. The beeping continues until the end of the
play.
- - - --
FUELVIDEO represents the red bar graph in
the upper left-hand corner of the blue field. This
video is generated by supplying the correct timing
signals to KSB and J6B. The countdown action of
the fuel display is caused by I Cs J3 and J4. IC K6
inhibits the flow of clock pulses to IC J3 until the
timer IC L1 in Figure A times out. When L1 times
out, pins 1 and 2 of K6 go LO. Output pin 3 of K6
goes HI and G-ON pulses the clock input to the
counter J3. This ·continues until FUEL= 0 and
pin 1 of L7 (Figure A) inhibits the multivibrator,
hence halting game play.
This concludes the discussion on the Gino
RondinaRally Race Video Game. I have covered
the more important points of each circuit and
hopefully enough information to meet your needs.
If you should encounter a problem you cannot
correct, you can contact the service department of
Kiddie Rides U.S.A. at 1-800-553-8000 for assist-
ance or send your boards to them with a description
of your problem. The boards will be repaired at a
nominal charge.
SYMPTOM/REMEDY CHART FOR GINO RONDINA RALLY VIDEO CAR
PROBLEM: When game is first initiated, the road
moves at SPEED4. Foot pedal controls sound
properly, but no change to the speed of the road.
FIX: Replace IC E13. Op Amp is defective.
PROBLEM: Car stays too far left of the screen. Cari
tilts when wheel is turned, but the car doesn't swing
across screen.
FIX: Replace F9 LM339 Op-Amp.
PROBLEM: Screen is predominately red. You can
make out the yellow cars, trees, center line of track,
sky, and score numbers. You cannot see tree trunks.
FIX: The TRONCHI (tree trunk) signal is not present
at pin 2 of IC C2. Check the inputs to ca. They all
should have a clock pulse train on them If this is the
case, and the output of ca is a constant HI or LO,
then change output IC ca.
PROBLEM: There are no flashing boxes before bonus
point markers. Instead, the width of the lines
change alternately.
FIX: YN BOX signal not present at IC AB. Replace
LM339.
PROBLEM: No road. No red car. No yellow cars. Just
trees and grass.
FIX: Op-Amp at location F9 defective. Replace
LM339.
PROBLEM: No green in pix. Video seems to be OK as
far as the various effects are concerned.
FIX: Inverter IC B3 defective or other fault at signal
lines to PROM A 11 . Replace B3.
PROBLEM: Car will move fast to the right but slow to
the left
FIX: Check the -5-volt power supply. This is a
zener diode on the power supply board If defective,
replace the diode and current limit resistor.
PROBLEM: Short red lines across the road. One
approximately every 3 to 3 ½ inches.
FIX: Install a .001 uf disc capacitor to pin 12 of IC
M3 to ground. Clean edge connector contacts on PC
board.
PROBLEM: Car moves across the screen but the tilt
of the car is jammed to one position.
FIX: LM-7 41 Op-Amp at D10 defective.
PROBLEM: Road and trees move excessively fast
vertically on the screen. Road may have a continuous
wavy motion to it
FIX: Flip-flop BS defective. Replace.
PROBLEM: Audio is distorted yet transistors check
out OK
FIX: Install a biasing diode between the bases of the
output transistors. Cut the copper trace and install
an I N-914 or equivalent
Continued on next page.