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16
The game is structured for 6 players/coin when switch
SI is in the "A" position; this forces the 4PLAY signal at F6
pin 6 and the 6PLAY signal at F6 pin 8 to always be high.
Deposit of the first coin will then cause all three GAME RESET
signals to occur, resetting all horses to the start line, and will
cause the BUG TRIG (bugle trigger) signal to initiate the
bugle sound sequence. Also the coin counter driver is trig
gered, and all front panel push buttons are lit.
A player depressing the start button causes the ATTRACT
signal lo be produced at F8 pin 6.
The game is structured for 2 players/coin when switch
S1 is in the 2/4/6 position. Deposit of the first coin will set
the credit latch, and the signal Q at H8 pin 2 will go high.
Q going high causes the coin counter F6 to be incremented,
the BUG TRIG signal to be generated, and the GAME RESET 1
signal forces horses #1 and #4 back to the start line.
Deposit of a second coin will clock the 4PLA Y signal to
high and the GAME RESET 1 and GAME RESET 2 signals will
be produced. Deposit of a third coin will clock the 6PLAY
signal to a high, and all three GAME RESET signals will be
produced. The bugle call sound is produced only after the
first coin is deposited. As each additional coin is deposited,
the next two horses will appear on the TV screen and those
jump push buttons will light up. As in the 6 players/coin
structuring, a player depressing the start button starts the
race; however, in 2 players/coin structuring, additional
players can join the race after it has started by depositing
more coins. Note· If additional players are added after the
game starts, all horses except the pace horse will be reset to
the start position.
The bugle sound circuit consists of time value
counter B8, the note sequencer formed by C7 and B7, the
ROM in location C8, and frequency synthesizer D8. The
bugle sound sequence begins when the BUG TRIG signal
resets the note sequencer at C7 pin 3 and via the gate input
D7 pin 12. Information from the note sequencer then
;i. d dresses the ROM. This information includes the frequency
of the present note (signals BUG I through BUG4) and the
time value of the next note ( BUG6 through BUG8). The
frequency data go to frequency synthesizer D8 and the time
value data to time value counter B8. Counter B8 first makes
the note sound for the proper amount of time, then incre
ments the note sequencer C7 and B7, and after that loads
new time value data. The BUG8 signal produced at C8 pin 9
signifies the end of the sequence.
3.4.13 BUGLE SOUND CIRCUIT (SHEET 1 ZONE D 3
AND 4):
3.4.14
The junction of resistors R87, R90,
R89, R88 and R74 forms a summing point for the sound
signals for the bugle, constant background crowd roar, gun
shot and fall, whistle and trot (gallop sound) circuits.
Transistor Q9 is a current-starved, zener-bi;i.sed noise
generator. Its output is buffered by amplifier ClO, and the
signal NOISE appears at C10 pin 1. A variab� attenuation
circuit involving Q8 and the signals C* and Q feeds a
changing-amplitude noise signal into an active band-pass
filter formed by amplifier Cl 0. The output at Cl O pin 7
adds the crowd roar sound heard in the background during
play.
To produce the gunshot and fall sounds, transistor Q6
charges capacitor C46 at the start of the game play and each
time a horse strikes a picket and falls. This decaying voltage
controls the gain of the saturating amplifier stage Q7, which
produces a burst of noise (a "bang") each time the circuit
is triggered. The output is band-pass filtered before the sound
summing point.
The whistle sound is produced by a type-556 timer
device in location F9. Half of this IC is connected as a long
time constant one-shot. It is triggered each time the leading
horse completes an additional one-eighth of the race. The
signal C* coming from F8 pin 8 provides the triggering. The
second half of IC F9 forms a VCO (voltage controlled oscil
lator) which is driven by the one-shot's timing capacitor
voltage and is gated by the one-shot pulse. The signal
WHISTLE is produced each time this circuit is triggered.
The type-9312 device in location E7 produces the gallop
sound by making a 3-out-of-4 pulse sequence based on timing
of the gallop rate signals X 1, X2 and X3.
The sound signals described in paragraphs 3.4.13
and 3.4.14 are mixed by operational amplifier Cl O; the out
put at pin 10 is coupled to a type-LM380 audio power
amplifier in location B9. The output at B9 pin 8 is coupled
to the speaker. The signal Q controls transistor QlO so that
Ql O turns on power amplifier B9 at the start of the game,
and disables it one second after the game ends.
OTHER SOUND CIRCUITS (SHEET
B,C,D 1 THROUGH 4):
3.4.15 AUDIO OUTPUT STAGE (SHEET 1 ZONE B 2
AND 3):
1
ZONES
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