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TEST/DIAGNOSTIC PROCEDURES
(Continued)
SYSTEM-1
t
B SOUND CIRCUITRY TESTS (Continued)
If no sound is heard, reterto the text entltfed ~NO
SOUND ...",
II wm'''ring!'
is heard, this Indicates
a malfunction ·of Ihe U23
RAM
Chip- II either ~
or
19y[
"rings" Is heard, this indicates
a
problem
associated with ·the U21
ROM
Chip, If either
tb.fli!I:
or!.iY§.
"rings:' is
heard,
this Indicates
a
problem
with the U22.
ROM
Chip,
NO SOUND DURING THIS.TEST{but
sound can be heard duringJhe Diagnostic Tests),
Check the
sound-select
inputs (pins 21hrough
9 6f
U9) to see
11
they pulse during 80und Test
01, Also, check the ,12 V supply voltage on the CPU BOard, If this voltage Js low (or AC ripple
seems too high), perform the lollowing checks:
1,
The
gray and gray.green transformer secondary wlres for 19.4 VAC,
2. The CP U BOard fiiler capacitor C26 for -1-2 VDG.
3. The llHercapaCilorC26 for excessive AG ripple (overO.75VAC),
If the prevl9uS checks did not isolate the proble m, turn the Volume Con\roi for maximum output.
Momentarily lauch a powered-up AC soldering pencil on the center tap
otthe
Volume Contrel,
©&1IJ1J'D@1M
DO
NOT
~se a sQlderlng;lron over 40 walts. Nole also that cordless solder·ing
irons
will
NOT work
tor this IEist.
!'-Iearing
a
low burn
(ir
a 'click'
1~iC;ates
that I~e power ainplifler
(Ui,
TDA2002),
the Volume Con-
trot
and the speaker,are operating satisfactorily,
as
is the sound circuit cabling_ Not hearing a hum
reQuires. re'peating the test
with
the Volume COlltrollUrneq
pan
way
down, to deJartnine whether
the Volume Control is faulty, Also, check the cable connectors lor proper mali'rIg, and that no
broken wires affect this circuit.
FUSE LISTING,
The following fuses are used:
Part Number
Description
5730-09252-00 Fuse, SA Slow-Blow (S~B),
1is"
5731-09S51-00 Fuse,
SA
S-8, 250'0'
57.30-09071.-,00 Fuse,
SA
8'8, 32'1
5730-12203-00 Fuse,
'!fI0A
s-a,
250'1
5 731-08~65"oa Fuse, 2A 5-'8; 250,\1
5731~09651-00 Fuse; 5A S-8; 250v
5731-06314-00 Fuse, 4A S,8, 250'1
5731 -08761-00 Fuse, 114A S-B,
250'1
5731-09432-00 Fuse, 7A S-B., 250'1
5731-09128-00
Fuse, 2:5A 8'B', 250v
Clrcu
Il/LocatlOn
Input Power ("high voHage") UneICabinel80x·
Gen. Illumination/Upper Rt 8aokbOx fuseholcfer (4)
+18
vee
Lamp
CW
Lwr
At
Backb;ox
luseholder
(1)
t
& -
1
OOVDisplay PwrlUpr Cntr B'bo'X !useholder
(2)
F1,
F3 -
FS; 0-liB13 Au'X Pwr Driver Board
F8; 0-11813 Aux Pwr Dliver Board
F.2, F7; D,11813
Aux
Pwr Oriver.Board
F1, 0-8345-557 P·ower Supply
F5, F6_;D-8345-5.57 Power Supply
8Ft, Len und_erside-ol playfield, neat pivot
• one
4A 8.B, 250v fuse (5731-06314-00) Is.provided for an overseas (220v) game lnstallaton,