Williams Electronics WHIRLWIND - System-11 B Sound Circuitry Tests; Problem Analysis Messages

TEST/DIAGNOSTIC
PROCEDURES
(Continued)
SYSTEM-11B
SOUND
CIRCUITRY
TESTS.
Tests
of
the
System-11B Sound
circuitry,
including
the Audio
Board, are possible only after
successful
completion
of the
System-11B
Memory
Chip
Test.
1
.Audlo
Board
Test.
A
brief check
of
the
Audio Board
(D-11581)
circuitry occurs at game
Turn-
on; the
game reports
the
test
results
by brief
sounds,
as
follows:
_N9_sQ_und
=
Audio Board is
not
operating,
or
a
failure is
affecting the
sound
circuitry
(broken
cable; dead amplifier; etc.); _1_
sound
=
system
OK;
2_sQun_d_s = RAM
problem;
3_sQund§
=
U4
problem;
fi_§Q_|,1flQ§ = U19
problem.
2
.General
System-11B
Sound
Test.
Press
the Sound Diagnostic
Switch (SW
1) on left
edge
of
the
CPU Board. Listen
for
the two
test
sounds, showing that both the CVSD (Continu-
ously
Variable
Slope Delta) Modulator, which
provides
the voices
for Whirlwind, and the DAC
(Digital—to—Analog
Converter)
sound
circuits
are
functioning properly.
If
no
sound
is
heard, refer
to
the text entitled
"NO
SOUND
indicates
a
malfunction
of the
U23
RAM Chip. If either
1ymor19_u1:"rings"
is heard,’ this indicates a
problem
associated
with
the
U21
ROM
Chip.
If
either
mgeeorfl ye
"rings"
is heard,
this indicates
a
problem
with
the
U22
ROM
Chip.
N0
SOUND
DURING
THIS
TEST(but
sound
can
be
heard
during
the
Diagnostic
Tests).
Check the
sound-select
inputs
(pins 2 through
9
of
U9)
to see
if
they pulse during
Sound Test
01.
Also,
check
the
-12
V
supply
voltage
on
the
CPU
Board.
If this
voltage is
low (or AC
ripple
seems
too
high),
perform
the following
checks:
1 . The
gray
and gray-green
transformer
secondary wires
for 19.4 VAC.
2. The
CPU Board filter
capacitor
C26 for -12 VDC.
3.
The filter
capacitor
C26 for
excessive
AC ripple (over
0.75VAC).
If
the previous
checks
did not
isolate
the
problem,
turn
the Volume Control
for maximum output.
Momentarily
touch
a powered-up
AC
soldering
pencil
on the
center
tap of the Volume Control.
@AU'iT|]©lNJ
DO NOT use
a soldering
iron
over 40 watts.
Note also that cordless
soldering
irons
will
NOT work for
this
test.
Hearing
a low hum
or
a
'click'iindicates that
the
power amplifier (U1,
TDA2002), the
Volume
Con-
trol, and the speaker
are
operating
satisfactorily,
as is the
sound circuit cabling.
Not hearing a
sound requires
repeating
the
test
with the Volume Control
turned part way down, to determine
whether
the Volume
Control
is
faulty.
Also,
check
the cable connectors
for proper mating,
and
that no
broken
wires
affect this circuit
.
PROBLEM ANALYSIS
MESSAGES.
The
SYSTEM
11B
game
program
has
a gr_e_a1_gaQa_b1lj1y
to
aid the operator
and service
personnel:
At
Game
Turn-on
(and
also at
the beginning
of the Test/Diagnostic
Procedures)
after
the game
has
been
operating
for
an extended
period, the
player
score
displays
now
may
signal
with
a
message.
"Press
ADVANCE
for
Report",
that
the game
program
has
detected
a possible
problem
with
the game.
To
obtain
details
of
the problem,
open
the
coin
door
and
press the
AUTO-UP/MANUAL-DOWN
switch
to
MANUAL-DOWN.
Press
the
ADVANCE button
to
begin
displaying
the message(s).
The following
messages
apply
to your
Whfl rllwllnd game.
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