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T
ROUBLE
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SHOOTING
G
UIDE
Below is a basic trouble-shooting guide to assist in seeking out and correcting a problem that may occur in the
installation process. Although lengthy, this chart cannot address every single problem possible but mainly the ones
most common.
SYMPTOM
No power (power light not on)
Power but no sound (power light is on)
No sound from one channel or entire side
Very low sound level
Power amplifier turns on and off repeatedly
(motor-boating sound)
Amplifier turns off during loud or distorted
passages
Amplifier performs fine but gets very hot to
the touch
Amplifier turn-on/turn-off pops or noises
Cracking noises on AM/FM radio but not on
tape or cd.
Whining noise, engine running, varies in pitch
or loudness with engine speed, AND varies
with radio volume control setting
(this is
generally a RADIO installation problem)
Whining noise, engine running, varies in pitch
or loudness with engine speed, BUT, DOES
NOT vary with radio volume control setting
(this is generally an amplifier installation
problem)
PROBABLE CAUSE OR CORRECTION
• Check connections to amps +12 volt, ground, and remote lines.
• Use voltmeter to verify voltages are at terminals of amp.
• Check main power connection at battery.
• Check fuse in power line at battery.
• Disconnect all speakers but not power lines - if unit then turns on, a speaker short or speaker
line touching vehicle chassis is likely.
• Check all input cable lines for connection.
• Disconnect speakers from amp, test speaker lines with digital voltmeter to verify >2 ohms per
channel (non-bridged mode).
• Check radio’s balance and fader control positions - verify they are at center.
• Check speaker connections at amp and speaker.
• Check input leads for connection to amp.
• Verify radio balance and fader controls are at center positions.
• Check amplifier’s input gain control setting - adjust for higher output levels if necessary (gain
settings closer to 0.3 volts).
• Receiver may have very low output voltage levels - a step up “line driver” may have to be
used.
• Make sure power connections at batter are tight.
• Verify battery voltage is >11.5 volts DC (12.5-15V engine on) at amplifier with engine off.
• Check all radio and amplifier ground connections.
• Input stage being over-driven - lower input gain (closer to 4 volt setting).
• Verify battery voltage is >11.5 volts DC at amplifier with engine off.
• Check all radio and amplifier ground connections.
• Verify speaker loads >2 ohms on all channels (non-bridged mode).
• Input gain control too high - lower accordingly (closer to 4.0 volt setting).
• Verify speaker loads >2 ohms on all channels (non-bridged mode).
• Verify the mounting location allows for free air movement around the amp. Preferably, the amp
should be mounted with fins up and down so rising heat moves quickly away from amp.
• “turn on race” - disconnect trigger from radio and turn on/off via a wire jumper to power
terminal. If noise goes away, the radio is turning on/off too slowly. This is radio problem and
can only be corrected with outboard turn-on delay relay system.
• Radio “thump” - disconnect the RCA input lines to the amp and turn on/off via radio trigger. If
noise goes away without RCA lines connected, the radio is sending pops out through RCA
lines. This is a radio problem and can only be corrected with outboard turn-on delay relay
system.
• Ensure the problem is “radiated noise” by placing a portable FM radio near the car engine. If
noise is picked up, then it is a vehicle problem and not your system. Research to isolate the
source and properly shield or bypass.
• Are spark plugs and wires > 3 years old? These can often radiate substantial noise when old.
• Verify the engine block has a good ground connection to chassis ground.
• Verify the engine compartment hood is grounded to vehicle chassis via a braided grounding
strap.
• Verify all power and ground connections are clean at radio.
• Re-route radio power and ground so they are sourced from same connections back at
amplifier (this is called a “common” ground).
• Check all ground connections to ensure clean surfaces that have all paint removed and also
not oxidation buildup over time.
• Verify there is some kind of power filtering choke assembly at back of radio. If not, install one.
• Check battery ground connections at chassis are clean and tight, scraped free of oxidation,
paint, and grease.
• Re-route radio power and ground so they are sourced from same connections back at
amplifier (this is called a “common” ground).
• Bypass all equipment between radio and amp (e.g., equalizers) directly connecting radio. If
noise goes away, signal processor has problem.
• Check for signal level “ground loops” - disconnect the outer shield of the RCA cable at one
end of the cable (e.g., radio end). If noise goes away, modify cables accordingly. There are
voltage differences at the ground connections of the components and these are NOT
correctable any other way than such shield cutting or an outboard “ground loop isolator”
which is a small transformer.
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