Williams Sinistar Instructions Service Manual

							9 Bookkeeping Totals
1. In Game-Over Mode, open the cashbox and depress
the cashbox advance switch.  The advance switch
located on the diagnostic switch bracket can also be
used.  (See Figure 1.)  The CRT should indicate all
bookkeeping and evaluation totals.  If so, go to step 3.
If the CRT display comes up in the ROM test, perform
step 2.
AUTO-UP
HIGH
SCORE
RESETMANUAL
DOWNADVANCE
Figure 1.  Coin Door Button Switches
2. Continue to depress the cashbox advance switch,
stepping the game through test programs for ROMs,
RAMs, CMOS RAMs, colour RAMs, sounds, switches,
and then CRT test patterns, of which there are five.
The fifth test pattern, colour bars, directly precedes the
CRT display of the bookkeeping and evaluation totals.
3. The bookkeeping and evaluation totals appear on the
displays as in Figure 2.
Figure 2.  Bookkeeping Display
Clearing Bookkeeping Totals
1. Depress ADVANCE to display Game Adjustments.
2. Operate joystick Up or Down to position cursor on
CLEAR BOOKKEEPING TOTALS.
3. Push FIRE Button.
4. Depress ADVANCE.
IF AVERAGE TIME PER CREDIT RUNS BELOW 1:30
(Figure 2), then more liberal GAME ADJUSTMENTS
 are
recommended.  What if AVERAGE TIME PER CREDIT
runs over 2:30?  Make the game tougher.  Always try to
keep AVERAGE TIME PER CREDIT close to the ideal of
2:00.
Game Adjustments
In the Game-Over Mode open the coin door.  With the
AUTO-UP/MANUAL-DOWN switch set to AUTO-UP, and
depress the coin door ADVANCE switch twice to cause
a CRT display as shown in Figure 3.
SELECT THE FUNCTION YOU WISH
 to change by
moving the joystick (push up to move arrow up, down  to
move arrow down)  Then, making sure the coin door is
open, push the FIRE button  to increase or SINIBOMB t to
reduce the value of the selected function.
 
Select the appropriate difficulty level by using the
SINIBOMB (easier) and FIRE (harder) buttons (0 =
easiest or liberal, 5 = average, 9 = hardest or
conservative).  
NOTE: The next two adjustments affect
playing time by making extra ships easier or harder to
win.  Details are on page 12.
 
For a shorter game, increase the bonus points figure
(FIRST EXTRA SHIP AT).  For a longer game, reduce
it. (1,000 = long / 99,000 = short).
 
For a shorter game, increase ADDITIONAL POINTS
PER SHIP AT.  For a longer game, decrease it. (1,000
= long / 99,000 = short).
 
For a shorter game, decrease the number of SHIPS
PER GAME.  For a longer game, increase the number.
(1 = short / 99 = long).
GAME PRICING 
is selected with standard settings or with
custom settings as shown in Table 1.  Note that free play
can be elected by entering the code number 9 at the
PRICING SELECTION function.
FOR STANDARD SETTINGS
 you need change only the
PRICING SELECTION.  For custom settings, first set
PRICING SELECTION to zero and then set the remaining
values according to Table 1.
BOOKKEEPING TOTALS
LEFT SLOT COINS   167
CENTER SLOT COINS       0
RIGHT SLOT COINS   426
PAID CREDITS     23
FREE SHIPS   221
TOTAL TIME IN MINUTES 1200
TOTAL SHIPS PLAYED 2000
TOTAL CREDITS PLAYED   593
AVERAGE TIME PER CREDIT
2:01 
						

							10
Figure 3. Game Adjustments
Showing factory settings
HIGHEST SCORE SIGNATURE
The number of letters allowed the highest scoring player for
entering his name can be varied from 3 to 20 and is
recommended as 3.  If objectionable words are entered as
the signature name, you can change the lettered entry
leaving the highest score the same.  See SETTING
HIGHEST SCORE NAME.
RESTORE FACTORY SETTINGS
1. Position cursor on RESTORE FACTORY SETTINGS.
2. Push FIRE button.
3. Depress ADVANCE twice.
RESETTING HIGH SCORE TABLE
1. Position cursor on RESET HIGH SCORE TABLE.
2. Push FIRE button.
3. Depress ADVANCE.
SETTING ATTRACT MODE MESSAGE
1. Position cursor on SET ATTRACT MODE MESSAGE.
2. Push FIRE button.
3. Depress ADVANCE.
4. Enter up to two lines of your message following
instructions on the screen
5.  Depress ADVANCE to terminate process.
To restore the Williams attract mode message, perform
steps 1 through 3 and then turn the game OFF and back
ON.
SETTING HIGH SCORE NAME
1. Position cursor on SET HIGHEST SCORE NAME.
2. Push FIRE button.
3. Depress ADVANCE.
4. Enter new signature; depress ADVANCE to terminate
process.
An alternate, simpler method enters the factory highest
score signature.  In the game over mode, hold HIGH
SCORE RESET Depressed.  After a few seconds a sound
is produced and the factory highest score signature has
been activated.
GAME ADJUSTMENTS
FIRST EXTRA SHIP AT 30,000
ADDI TIONAL EXTR A SHIP
   POINTS FACTOR 30,000
SHIPS PER GAME          3
DIFFICULTY OF PLAY          5
CONTINUOUS FIRE
    YES
HIGH SCORE TO DATE
AL LOW ED
    YES
PRICING SELECTION          3
   LEFT SLOT UNITS          1
   CENTER SLOT UNITS          4
   RIGHT SLOT UNITS          1
   UNITS REQUIRED FOR CREDIT          1
   UNITS REQUIRED FOR BONUS
      CREDIT          0
   MINIMUM UNITS FOR ANY
      CREDIT          0
RESTORE FACTORY SETTINGS       NO
CLEAR BOOKKEEPING TOTALS       NO
HIGH SCORE TABLE RESET       NO
AUTO CYCLE       NO
USE ‘MOVE’ TO SELECT
ADJUSTM ENT
USE ‘FIRE-SINIBOMB’ BUTTONS TO
CHANGE THE VALUE
PRESS ADVANCE TO EXIT 
						

							11
Table 1.  Game Pricing
Coin Door
MechanismCredits/
MoneyPricing
SelectionLeft
Slot
UnitsCentre
Slot
UnitsRight
Slot
UnitsUnits
Per
CreditUnits
Reqd
For
Bonus
CreditMin
 Units
For
Any
Credit
•
•• • 
1/25¢, 5/$10141140
•
•• • 
2/50¢, 5/$10141142
•
•• • 1/25¢, 4/$13141100
•
•• • 
2/50¢, 4/$10141102
•
•• • 
1/50¢, 3/$1, 4/$1.25031234150
•
•• • 
1/50¢, 3/$1, 7/$20 124812149624
•
•• •  1/50¢, 3/$1, 6/$21141240
Twin Quarter
Quarter, Dollar, Quarter
•
•• • 1/50¢5141200
1DM, 5DM
•
•• • 1/1DM, 6/5DM2601100
20-Cent, 50-Cent
•
•• • 
1/20¢, 3/50¢06015500
1 Franc, 5 Franc
•
•• • 1/2F, 3/5F44166200
25 Cent
•
•• • 1/25¢, 4/1G6104100
1 Guilder
•
•• • 
1/25¢, 5/1G0104140
5 Franc
•
•• • 1/5F, 2/10F7102100
10 Franc
•
•• • 1/10F8102200
1 Franc, 2 Franc
•
•• • 2/1F 5/2F2601100
100 Lire, 200 Lire
•
•• • 1/200 Lire8102200
•
•• • 1/1 Coin3141100
•
•• • 1/2 Coins5141200
Twin Coin
•
•• • 
1/3 Coins, 2 5 Coins0202500
•
•• • 1/2, 3/541166200
•
•• • 
1/1, 5/50105100
1-Unit, 5-Unit
•
•• • 
1/3, 2/502010500
Any
•
•• • Free Play9141100
Definitions of Pricing Terms
PRICING SELECTION
 allows a 
shorthand method of
setting the pricing functions.  If a number from one to nine
is entered into the PRICING SELECTION function, a
corresponding standard setting (shown in bold type above)
will be entered into the game.  
The rest of the pricing
functions are automatically set for that standard.
THE PRICE OF ONE GAME
 (number of coins per game) is
equal to the number of SLOT UNITS for any one slot
divided by the number of UNITS PER CREDIT.  If the
number of LEFT SLOT UNITS (or RIGHT SLOT UNITS)
equals 
X and the number of UNITS PER CREDIT equals
Y, then the 
price of one game is X/Y
UNITS REQUIRED FOR BONUS CREDIT
 is the number of
games that must be purchased before a free game is
awarded.
MINIMUM UNITS FOR ANY CREDIT
 is the least number
of coins allowed per game or games.  Or put another way,
the MIMIMUM UNITS FOR ANY CREDIT determines the
smallest number of whole games that may be paid for at
one time.For example if an operator wants to allow one play for a
quarter but wishes to encourage multiple game playing, he
may enter:
•
•• • 
0 in the PRICING SELECTION function
This zero value automatically sets all pricing functions.
However minimum units for any credit must be raised to 2
or higher value to achieve the operators goal.  Here are the
rest of the functions as they should appear.
•
•• • 
1 in the LEFT SLOT UNITS function
•
•• • 
4 in the CENTER SLOT UNITS function
•
•• • 
1 in the RIGHT SLOT UNITS function
•
•• • 
1 in the UNITS PER CREDIT function
•
•• • 
0 in the UNITS REQUIRED FOR BONUS
CREDIT function
•
•• • 
2 in the MINIMUM UNITS FOR ANY CREDIT
function
These values allow one game to be played for a quarter,
but ONLY when two or more games are paid for at a time.
Incidentally, the 4 in the CENTER SLOT UNITS allows
four games per dollar coin (centre slot only).  See 2/50¢,
4/$1 above. 
						

							12
SAMPLE SETTINGS
Before adjusting EXTRA SHIPS settings, review the chart to see how they affect the extra ship score.
LET
FIRST EXTRA SHIP AT = F
ADDITIONAL EXTRA SHIP POINTS FACTOR = A
EXTRA
SHIPFORMULA
1F = 10,000
A = 0000F = 10,000
A = 10,000F = 30,000
A = 10,000F = 10,000
A = 30,000
1st  F 10,000 10,000 30,000 10,000
2nd2F + 1A 20,000 30,000 70,000 50,000
3rd3F + 3A 30,000 60,000 120,000 120,000
4th4F + 6A 40,000 100,000 180,000 220,000
5th5F + 10A 50,000 150,000 250,000 350,000
1This series is derived from:
(n
2-n)AnF   +
2
where n is the extra ship no. 
						

							13
CHAPTER 3  Troubleshooting Procedures
Introduction
Power-Up Tests
+5v DC Power Supply Adjustments
Self-Diagnostics
Diagnostic Mode Tests
Sound Board Diagnostics
CMOS RAM Data Test Protocol 
						

							14
INTRODUCTION
Certain types of game malfunctions may inhibit the games
diagnostic or display faculties.  Troubleshooting procedures for
most of these types of malfunctions as well as malfunctions that
permit self-diagnosis are covered below.  Our troubleshootingalgorithm begins with 
Power-Up and continues until 
Game Over
Mode.  All procedures can be performed with minimal test
equipment or merely by observing the game itself.
POWER-UP TESTS
NO GENERAL
ILLUMINATIONNO INITIAL VIDEO
(RUG PATTERN)CHECKING POWER
SUPPLY BOARD
(1) Check fuse F2 on power supply board.
(2) Check for proper installation of jumpers
W1, W2, W3 and/or resistor R27. (Some
machines DO NOT have an R27. Refer to
your drawing set.)
(3) Check 4P1/J I, 4P3/J3, 6P2/J2 and
6P3/J3.
(4) If all the above dont turn up the problem
check power supply board.(1) Press reset button on CPU Board.
(2) Try RAM and ROM tests (see below)
(3) If all the above dont turn up the problem,
check power supply board.(1) Swap power supply board with one from
known-good game.
(2) If game plays, problem is on power
supply board.
(3) If game doesnt play, check power
transformer with voltmeter.
(4) If known-good power supply is
unavailable for  tests above, check +5V, –
5V and + 12V outputs on power supply in
game.   Each MUST BE within 2% of rated
output with less than 0.1% AC hum.
MORE POWER-UP TESTS
TEST ROM BOARD
LEDs RECOGNIZE
CONDITIONROM BOARD LEDs
IDENTIFY BAD
CHIPSVIDEO REMEDY
GENERAL “0” means all
power-up tests
passed- (1) Scanning rug pattern
(2) Stationary rug pattern
(3) INITIAL TESTS INDICATE ALL
SYSTEMS GO
(4) Game-Over ModeIf any video (see left) is missing or
error message is displayed,
proceed to 
Diagnostic Mode
tests.
“0” means tests
passed- “HIGH SCORE TABLE RESET”
“BOOKKEEPING TOTALS CLEARED”
“ADJUSTMENT FAILURE”
“RESTORE FACTORY SEITINGS
BY OPENING FRONT AND
TURNING GAME OFF AND ON”(1) Open coin door and turn
power off and on.CMOS (See
Appendix A)
“0” means tests
passed- “FACTORY SEITINGS RESTORED” (2) Press ADVANCE.  Game
should return to Game-Over
Mode.
BATTERY (See
Appendix A)“0” means tests
passed- “HIGH SCORE TABLE RESET”
“BOOKKEEPING TOTALS CLEARED”
“ADJUSTMENT FAILURE”
“RESTORE FACTORY SEITINGS
BY OPENING FRONT AND
TURNING GAME OFF AND ON”(1) Open coin door and turn
power off and on. Or press
ADVANCE.  In either case, game
should return to Game-Over
Mode.
(2) Check AA alkaline cells on
CPU Board.
(3) If problem persists proceed
with CMOS RAM test by putting
the game into its 
Diagnostic
Mode (see SELF-
DIAGNOSTICS).
MEMORY
PROTECT
INTERLOCK
(See
Appendix A)“0” means tests
passed- “HIGH SCORE TABLE RESET”
“BOOKKEEPING TOTALS CLEARED”
“ADJUSTMENT FAILURE”
“RESTORE FACTORY SEITINGS
BY OPENING FRONT AND
TURNING GAME OFF AND ON”(1) Making and breaking coin
door interlock switch, check with
VOM and replace if faulty.
(2) Replace if faulty: Memory
protect gates 6E, IC1, Ql, or
CMOS RAM 1C.
SPECIAL CHIP “0” means tests
passed- (1) Scanning rug pattern.
(2) Blank screen instead of “INITIAL
TESTS INDICATE: OPERATIONAL”
(3) High score table with no scores.
(4) Intro blank or program crash.(1) Turn power off.
(2) To find bad chip replace 2
special chips one at a time with
known good chips.
(3) Turn Machine on after each
replacement and run through
Power-Up Tests. 
						

							15
Figure 4. RAM Location and Numbering on the CPU Board & ROM Board RAMs
+5v DC Power Supply
Adjustments
Before adjusting the voltage output
, always check the
output at the supply for AC hum.  This hum should never
rise above 0.005v on the +5v DC supply.  If it does, consult
your schematic drawing set for proper DC voltages
throughout the circuit.
Test for these with the DC setting of your multimeter.  Make
a second check using the AC setting.  Pay particular
attention to readings at TP5 (top of capacitor C10).  If the
voltage here is too low (less than +11v DC) or you find
excessive ripple (more than 700mv rms), replace the
capacitor.
If TP1 is less than +4.95v DC remove R10.  If TP1 is still
less than +4.95v DC, the check precision resistors R25 and
R26.  If they are within 1% tolerance, the check IC2
.
Self-Diagnostics
If RAM or ROM failure messages are displayed on the CRT
after the “rug pattern” proceed with self-diagnostics.  Self-
diagnostic procedures are controlled by the AUTO-
UP/MANUAL-DOWN and ADVANCE switches in the coin
door. (See Figure 1.)
Set the AUTO-UP/MANUAL-DOWN switch to the
MANUAL-DOWN position and depress the ADVANCE
pushbutton.  The game is now in its Diagnostic Mode
 anda ROM test is performed.  With ROM test results present
on the CRT display, depressing the ADVANCE pushbutton
initiates the RAM test.
Further tests (CMOS, sound, switch, colour RAM, monitor
test patterns) are encountered one after the other as the
ADVANCE pushbutton is depressed (once more for each
subsequent test).
MONITOR TEST PATTERNS
 
(19 Monitor Upright Games
Only).   For ease in monitor adjustments, the monitor may
be slid back and the screen viewed in the CRT mirror
provided on the inside-top of the cabinet.
Remove the two bolts and carefully slide the monitor back
in its shelf; secure the monitor in the extended position by
inserting the two bolts though holes in the monitor base
and monitor shelf provided at the left side of the monitor.
AUTO CYCLE MODE
 - From the colour bar pattern (or
Game Over with the switch set to AUTO-UP) depress
ADVANCE two times to display GAME ADJUSTMENTS.
1. Position the cursor on AUTO CYCLE with the Joystick
and push the FIRE button.
2. Depress ADVANCE.
3. The system will now sequence through ROM, RAM,
and CMOS RAM tests repeatedly.  The coin door must
be open during the Auto Cycle test.  If an error is
detected, the test is terminated and the failure
indication is displayed on the CRT.
4. To terminate the Auto-Cycle test, turn the game OFF
and ON. 
						

							TROUBLESHOOTING PROCEDURES:
DIAGNOSTIC MODE TESTS
TEST ROM BOARD LEDs
RECOGNIZE
CONDITIONROM BOARD LEDs
IDENTIFY
CHIPSVIDEO REMEDY
ROM “2” means ROM error 2-digit ROM chip
number“ROM ERROR” and ROM chip
number.(1) Turn power off.
(2) Replace suspected chip.
RAM “1” means RAM error Bank number first,
then chip number in
bank (see figure 4)
*(For RAM Error 41
or 42 See Note)“RAM ERROR” followed by
RAM bank number and chip
number (Note: with multiple
RAM failures this display may
not appear) *(1) Check for normal voltages on indicated
RAM chip: -5v/pin 1, +12v/pin 8, +5v/pin 9.
(2) Turn power off.
(3) Replace suspected chip.
(4) With multiple RAM failures always check
power supply. See POWER-UP TESTS.
CMOS (See
Appendix A)“3” means CMOS
RAM error- “CMOS RAM ERROR OR
WRITE PROTECT FAILURE”(1) Check pin 22 of CMOS RAM for +3.2VDC
minimum. If present, replace CMOS chip 1C. If
absent replace AA alkaline cells.
(2) With new alkaline cells, check for +3.8v DC.
If still absent, replace diodes D9 and D10.
(3) Upon power-up and re-entry into diagnostics
if CMOS error message persists, check CMOS
RAM memory protect and address decoding
circuits with a logic probe.
Tests 4 and 7 provide sequential subtests.  To stop automatic cycling set switch to MANUAL-DOWN. Depress
advance in MANUAL-DOWN to step through subtests.  LED indications are not made for these tests.
TEST & PROCEDURES VIDEO REMEDY OR ADJUSTMENT
Missing Check1
2
3
4
5
6
All2P4/lOP3 Pin 3
2P4/10P3 Pin 2
2P4/10P3 Pin 5
2P4/10P3 Pin 4
2P4/10P3 Pin 7
2P4/10P3 Pin 6
Perform 
Sound Board Diagnostics
(see below)SOUND
(Test 4)“SOUND LINE 1”
“SOUND LINE 2”
“SOUND LINE 3”
“SOUND LINE 4”
“SOUND LINE 5”
“SOUND LINE 6”
(These appear one at a time)
NOTE:  If any two sounds are the same, check for
a short between the select lines with the same
sound.
CRT indicates AUTO-UP closed and any stuck
switches
. CRT Display for Each Switch . . .
ROM BOARD INTERFACE BOARD
SWITCH TEST
(Test 5)
(1)  Set switch to MANUAL-DOWN
and clear any stuck switches.
(2)  CRT should indicate no
switches closed.
(3)  Operate switches and check
for display of switch name.ADVANCE
AUTO-UP
HIGH SCORE
RESET
LEFT COIN
CENTRE COIN
RIGHT COIN
SLAM SWITCH1- PLAYER START
2- PLAYER START
UP-DOWN A1
UP-DOWN B1
UP-DOWN C1
UP-DOWN DIRECTION 1
RIGHT-LEFT A1
RIGHT-LEFT B1
RIGHT-LEFT C1
RIGHT-LEFT DIRECTION 1
FIRE 1
SINIBOMB 1(Refer to CABINET WIRING Diagram)
(1)  COIN DOOR SWITCH STUCK: Disconnect
2P3
(2)  PLAYER PANEL SWITCH STUCK:
Disconnect 3P2 or 3P3
(3)  COIN DOOR SWITCH DOES NOT
OPERATE: Ground corresponding pin of 2P3.
(4)  PLAYER PANEL SWITCH DOES NOT
OPERATE: Ground corresponding pin of 3P2 or
3P3
  SYMPTOM REMAINS SAME . . .ROM Board or
Interface Board Faulty.
  SYMPTOM CLEARS UP . . .Problem is in
switches or  wiring
ADDITIONAL TESTS FOR OPTOSWITCHES:
(5)  Check that +5v DC is at pin 1 or 12P1.
(6)  With joystick in centre position, check for 0.7v
at base of ON transistor(s) (Q1 thru Q6) and 0.1v
at pin(s) 2, 3, 4, 6, 7 and 8 of 12P1
(7)  With joystick moved from centre position,
check for 0.1v at base of OFF transistor(s) and 5v
at pin(s) 2, 3, 4, 6, 7 and 8 of 12P1
(8)  With joystick in centre position, check for 5v at
pin(s) 5 and 9 of 12P1.  With Joystick in Down
(Left) position, check for +5v at pin 5 (9) of 12P1.
With Joystick in Up (Right) position, check for +0v
at pin 5 (9) of 12P1.
NOTE: Two static RAMs located on the ROM board are indicated as RAM 41 in chip location 6D and RAM 42 in
chip location 4D. 
						

							MORE DIAGNOSTIC MODE TESTS
TEST & PROCEDURES VIDEO SEQUENCES REMEDY OR ADJUSTMENT
REPLACE RAM 1B REPLACE RAM 2B
1)  light red screen
2)  red screen
3)  dark red screentoo-light or
too-dark red
or grey bandmagenta band
4)  light green screen
5)  green screen
6)  dark green screenyellow band cyan band
7)  light blue screen
8)  blue screenmagenta band too-light or too
-dark blue or
grey band
4)  light green screen green band dark green band
or grey band
5)  green screen light green band dark green band
or grey band
COLOUR RAM TEST
(Test 6)
Note that a blank sequence
 or two sequences with the
same shade indicate a faulty 1A flip-flop, 1B RAM or 2B
RAM or a failure in the colour analogue circuit.  Check
voltages on Q1 (green transistor), Q2 (red transistor) and
Q3 (blue transistor).  During the eight full screen colour
tests, the base voltage (centre Pin) on each transistor
should vary between 3.8v (brightest colour) and 4.4v (no
colour)
Colour 
RAM check
(1) CRT sequences through 8
colours, 2 seconds each
(2) Thick vertical band
indicates colour RAM fault.
6)  dark green screen - grey band
cross hatch pattern Aids you in setting up
 vertical and
horizontal linearity, convergence and focus.
red screen
green screen
blue screen
colour barsAids you 
in optimising colour purity
MONITOR & COLOUR RAM TEST
(Test 7)
MAGENTA
CYAN
YELLOW
WHITE
BLACK
BLUE
GREEN
RED
Colour Bar Patterncolour bars
• double-width
• half-width
• transposed
• missingIf colour RAM test 6 indicates 
no faults,
symptoms at left suggest a fault in 1A, 1B,
2B or 2C chips. 
						

							SOUND BOARD DIAGNOSTICS
SYMPTOM TEST & PROCEDURES
  CHECK SOUND SELECT INPUTS
TEST TOOL CONDTION & REMEDY
Sound board connector
10P3/J3-2 to 7Logic Probe (Game on
and in test 4)•  PULSING - Proceed.
•  LOW - check jacks, foils.
•  STILL LOW - Perform ROM
board checkbox below.
SR1 DIP resistors
R3 to R9VOM - Reading ohms
(game off)•  ALL 4.7K - Proceed.
•  ANY OPEN - replace SR1.
C3 to C9 VOM - Reading ohms
(game off)•  ALL OK - Proceed.
•  ANY SHORTED - replace bad.
IC 5-1, IC 7-14
(power pins)Logic Probe (Game on
and in test 4)•  HIGH - Proceed.
•  LOW - Replace C19 (IC5) or C21
(IC7).
•  STILL LOW - Replace bad IC.
IC5-2, 4, 6, 10, 12, 15
IC7-4, 6Logic Probe (Game on
and in test 4)•  PULSING - Proceed.
•  LOW - Replace bad chip.
IC10-18, 19
(PIA)Logic Probe (Game on
and in test 4)•  PULSING - Proceed.
•  LIFT C20 - Retest.
•  PULSING NOW - Replace C20.
•  STILL LOW - Replace IC6,
retest.
MISSING SOUNDS
NO SOUND-STEP 1
(ASSUMPTION:
INPUT SECTION
FAILURE)
IC10-10 to 17
(PIA)Logic Probe (Game on
and in test 4)•  PULSING - Proceed.
•  SOME LOW Replace IC.
•  ALL LOW - Lift C31, retest.
•  PULSING NOW - Replace C31.
•  STILL LOW - Replace IC
NOTE: In cockpit model games where no sounds are produced from either sound board, disconnect both 9-pin connectors from
one board and then the other.  This isolates faults to a single Sound Board.  If sounds are still nit produced from either board
check ROM Board outputs on page 19 first.