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TEST/DIAGNOSTIC PROCEDURES (Continued)
CPU LED Indicator Codes Table
Diagnostic
LEU
Bllnks/
Dlspl,,;\,'
Me~saJ!(_"-
Explanation
Flushes
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 turned off).
2
MEM. PFiOl
FAILURE This message means that (A) the Coin Door may be shut; (8) the Mem-
ory Protect Switch may be stuck in the ON position; (C) the memory
protect logic is protecting the memory; or (0) a U25 RAM failure is
occurring. (See Note 1)
-'
U51 PIA FAILURE
U51
has a n-,alfUllc1ion,
(See Note 2)
4
U38 PIA FAILURE
U38 has a mCl'function. (See Note 2)
5
U41 PIA FAILURE
U41 has" rnartuncrton. (See Note 2)
6
U42 PIA FAILURE
U42 has a malfunction. (See Note 2)
7
U54 PIA FAILURE
U54 has a rn.alfurrctiori. (See Note 2)
8
U10 PIA FAILURE
U10 has a mc:dfunction. (See Note 2)
9
IRO FAILURE
IRO ha.s a malfunction. It may be missing or too fast or too slow.
10
U27 ROM FAILURE
U27's internal checksunls do not n1atch.
It may be a ROM failure, or its
associated conneciions and connectingdevices are causing .,
10
ap-
pear to have a pr
obte
rn.
(The following U26 test is skipped.)
1 1 U26 ROM FAILURE U26's internal checksums do not match.
Notes:
I. This test
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[hal [he C"ill
1)"<,,.
is
()PEN;
it is initiated
()NL
Y
by
pres sirrg the CPU
Dia~n()stic
S,vitch (SW2).
2. Altcnl~\tl\''l.'ly~
Its assocl;lle.._t
ct.)Ilnecti(Hl
...;tH"
l..:~).llnecting
devices. a
i'c
causing the 1(: to
LlP~
Pc..";;'U·
tp
have pn ..)bh ..
'1l1S.
SYSTEM-11 B SOUND CIRCUITRY TESTS.
Tests of the System-11 B Sound circuitry, including the Audio Board, are possible only after
successful completion of the System-11 B Memory Chip Test.
1 . Audio Board Test. A brief check of the Audio Board (0-11581) circuitry occurs at game
Turn-on; Ihe game reports the test results by 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 sound
=
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 JOKERZ, and the DAC
(Digital-to-Analog Converter) sound circuits are functioning properly,
If no sound is heard, refer to the text entitled "NO SOUND ... ". If one "ring" is heard, this
indicates a malfunction of the U23 RAM Chip. If either two or four "rings" is heard, this indicates
a problem associated with the U21 ROM Chip. If either three or ~ "rinqs" is heard, this
indicates a problem with the U22 ROM Chip.
NO SOUND DURfNG THfS 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 tor 19.4 VAC.
2. The CPU Board filter capacitor C26 for -12 VDC.
3. The filter capacitor C26 for excessive AC ripple (over O.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.
JOKERZ 35