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SYSTEM-ll C SOUND CIRCUITRY TESTS
Tests of the System-IIC Sound circuitry. including the Audio Board. are
possible only after successful completion of the System-II C Memory Chip
Test.
Audio Board Test.
A brief check of the Audio Board (0-11581) circuitry
occurs at game Tum-on; the 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
=
UI9 problem: 5 sounds=U20.
If the this test did not isolate the problem. tum the Volume Control
for maximum output. Momentarily touch a powered-up AC soldering iron
on the center tap of the Volume Control.
Be sure the Audio Board has +12V. -I2V. +5Vand Ground.
CAUTION
DO NOTuse a soldering iron over 40 watts. Note also that cordless
soldering irons will NOTwork for this test.
Hearing a low hum or a 'click' indicates that the power amplifier.
the Volume Control. 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 .
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Test/Diagnostic Procedures 1-43