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TEST/DIAGNOSTIC PROCEDURES (Continued)
CPU LED Indicator Codes Table
Diagnostic LED
Bllnksl
Display Message
Explanation
Flashes
1 U25 RAM FAILURE U25 RAM could not be used properly (NO other tests are performed;
the game is locked here, until the game is tumed off).
2
MEM. PROT. FAILURE This message means that (A) the Coin Door may be shut; (9) the Mem-
ory Protect Swit<::hmay be stuck in the ON position; (C) the mamory
protect logic is protecting the memory; or (D) a U25 RAM failure is
occurring. (See Note 1)
3
U5t PIA FAILURE U51 has a malfunction. (See Note 2)
4 U3B PIA FAILURE U38 has a malfunction. (See Note 2)
5
U41 PIA FAILURE U41 has a malfunction. (See Note 2)
6
U42 PIA FAILURE U42 has a malfunction. (See Note 2)
7
U54 PIA FAILURE U54 has a malfunction. (Seo Note 2)
8
Ul0 PIA FAILURE U10 has a malfunction. (5oe Note 2)
9
IRQ FAILURE
IRO has a malfunction. It
may
be missing or too fast or too slow.
10
U27 ROM FAILURE U27's intomat checksums do not match. It may be a ROM failure, or its
associated connections and connectingdevices are causing it to ap-
pear to have a problem. (The following U26 test Is skipped.)
11 U26 ROM FAILURE U26's internal checksums do not match.
Notes: 1.
This test assumes that the Coin Door is
OPEN;
it is initiated
ONLY by
pressing the
CPU
Diagnostic Switch
(SW2).
2.
Altematively.
its associated connections or connecting devices are causing the
I'C
to ap-
pear to have problems.
SYSTEM-11 B 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. Audio Board Test. A brief check of the AudiOBoard
(0-11581)
circuitry occurs at game Tum-
an; the game reports the test resuHsby brief sounds, as follows: No sound
=
Audio Board is
not operating, or a failure is affecting the sound circuitry (broken cable; dead amplifier; etc.);
1
~ "" system OK; 2 sounds
»
RAM problem; 3 sounds", U4 problem; 4 sounds
=
U19
problem.
2. General
System.11 B 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 BAD CATS, and the DAC
(Digital-to-Analog Converter) sound dreutts are functioning properly.
If no sound is heard, refer to the text entitled
"NO SOUND ...".
If Q.D.a "ring" is heard, this
indicates a malfunction of the U23 RAM Chip. If either
t::.m
or
1Qw:
"rings" is heard, this indicates a
problem associated with the U21 ROM Chip. If either
l.b.ma
or
frtB.
"rings" is heard, this indicates
a problem with the U22 ROM Chip.
NO 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 0.7SVAC).