Coustic 240SE - Manual (Page 9)

T RO U B L E - S H O OT I N G S E C T I O N
SYMPTOM PROBABLE CAUSE
1 No power Check connections to the amplifier's Ground, B+ & Remote
terminals. Check connection at "+" terminal of the battery.
Check the remote turn-on terminal. Ensure it receives power
when the source is turned on (or when the switch is turned
on). Refer to the Installation Section. Check the power line
fuse: if a fuse is blown, replace it; if fuse continues to blow,
check the power wire and also the amplifier for short. If the
short is in the power wire, fix it; if the short is in the amplifier
itself, see your Coustic dealer.
Check the voltage at the amplifier, and the remote ON/OFF
lead. The voltage should measure between 11 V-15V. If the
measurement is beyond this range, have the source unit
checked out by an authorized dealer.
2. Power without sound with Turn the amplifier off, and Check all input & output signal
red power/protection cables and connections. Check the speakers for a short with
indicator on a VOM or by connecting them to another audio system. After
making sure everything is normal, turn the amplifier on again.
3. Power without sound with The continuous red light of the power indicator signals high
red power indicator on internal operating temperature which results in the amplifier
switching off temporarily; when the amplifier cools down to a
safe level, the amp will automatically restart.
4. No sound from one side Check balance control.
Check speaker connections.
Check signal input connection.
5. Very low sound from Check your radio's fader control.
both radio & tape Check the amplifier's Input Sensitivity Level.
6. Frequent automatic amplifier This indicates that the amplifier is operating at a continually
shut down undesirable high internal temperature.
High operating temperature can be caused by inadequate
ventilation. (Refer to the sub-section titled LOCATION for a
better amplifier location.)
High operating temperature can be caused by an excessively
low impedance load, say below 2 ohms. Check for bad
speakers and/or electronic crossover, proper passive
crossover components; if all else fails, try rewiring the entire
system.
A high operating temperature may be caused by an incorrect
input sensitivity level (refer to sub-section titled INPUT
SENSITIVITY ADJUSTMENTS for correct setting).
7. "Motorboating": The amplifier Check the amplifier's connection to the battery.
power indicator going off Check battery voltage. If low, recharge or replace battery.
repeatedly when the audio Check all ground connections.
system is on.
SYMPTOM PROBABLE CAUSE
8. Whining noise when Reroute power cable from the battery to the source unit
engine is running with noise directly, bypassing the battery terminal in the fuse box.
varying with the accelerator Check power connections to be sure they are clean.
(noise level varies with Check ground connections to be sure the ground wire is in
source unit volume control). direct contact with the bare metal surface of chassis (with that
spot scraped clean of any paint).
9. Constant level whining noise Check for a ground loop in the system. Turn the system off
(most noise with source unit and one by one change the ground connections
volume at minimum) (by changing to a different contact point, scraping the level
constant irrespective of metal clean of any paint, rust or
grease). Turn the system on and check for whining noise after
each ground change.
CAUTION: Do not disconnect the Power Amplifier's ground when
the system is on. This could damage the amplifier.
Check for defective signal cables. Disconnect signal cables
at the amplifier and listen carefully for noise. If the noise dis-
appears, run a test pair of signal cables. If there is no unde-
sirable whining noise, reconnect to the amplifier with the new
pair of signal cables. Check the battery ground connection to
the vehicle chassis to make sure it is tight and clean.
Check the battery negative terminal connection to make sure
it is tight and clean.
10. Radiated noise: crackling Check if the noise is actually radiated noise: Tune a portable
noise on FM which is not radio to the same FM station. Move the portable radio close
present when playing tape to the vehicle engine. If crackling noise comes from the
or CD (noise varying slightly portable radio, then the noise you have in your vehicle audio
with accelerator, but is system is radiated noise.
present at all times) Check with a VOM to make sure the antenna is really ground-
ed to the vehicle chassis.
To ensure a true ground, break the plastic covering of the
antenna lead and solder a piece of heavy wire (minimum 14-
gauge) to the braided shield.
Ground the other end of the wire at the same point as the
radio ground.
Check spark plug wires. They should be suppression-type
wire and less than 2 years old. Otherwise, replace them with
good quality suppression cables.
Make sure the engine block is grounded to the vehicle chas-
sis at a bare metal spot (scraped clean of paint, rust and
grease).
Make sure hood is also grounded. If not, use a ground strap
(which is available from any auto parts store) to ground the
hood to the vehicle chassis.
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