Page 14 of 16 SC-409-10 Installation and Operating Instructions
11/10/05 CP4958A
SERVICE
This unit is designed to provide years of reliable service under even the worst conditions. Many
times there may appear to be a problem with the unit when the true problem is in the speaker(s),
controlled devices, or improper installation. The following chart shows typical symptoms and
possible causes.
A blown siren fuse doesn't necessarily mean that the unit is bad. If a speaker or speaker lead is
shorted the internal fuse will blow before the unit is damaged. Disconnect the speaker leads and
replace the fuse. If the OUTPUT light comes on with power on and Yelp selected it is OK. Check
the speaker(s) or leads for possible shorting.
PROBLEMS
Symptom Possible Cause Check
No power or siren
output
No power to enable input
Bad speaker
Connector(s) loose
Rear panel fuse blown
Loose connection at power source
Does backlighting come on?
Do you hear a "pop" when turned on?
With siren on and Yelp selected, listen for tone in amplifier.
Is an external fuse or circuit breaker used?
Are the negative leads connected to a good ground?
No siren tone -
PA works
High Voltage Protection
Microphone button stuck
Cutout activated
Cutout Polarity Option set wrong
Input voltage must be less than highest rated voltage.
Does microphone button release properly?
Does the siren work when Cutout input is disconnected?
Is the CUT_P option properly configured?
No PA PA volume not set properly Have you tried turning the PA volume control?
Distorted siren
sound
Speaker assembly loose
Intermittent Aux Input connection
Low vehicle voltage
Is the speaker bell or tip loose?
Is the Aux Input used and wired properly?
Input voltage must be greater than lowest rated voltage.
Intermittent siren
tone
High Voltage Protection
Connector loose
Bad power connection
Microphone button activation
Circuit breaker in supply connection
Is the vehicle voltage regulator working properly?
Is the connector tight on the back of the unit?
Is there a loose connection on a power lead?
Is something lying on the microphone?
Is a circuit breaker used with at least a 50A rating?
Horn function
stuck on or
Manual stuck on
Horn or Manual switch stuck
Aux Input improperly connected
Aux Input Polarity Option set wrong
Does the horn or manual switch return when released?
Is the Aux Input used and wired properly?
Is the AUX_P option properly configured?
No Radio Unit not connected to radio
Radio volume too low
Is the radio connected properly to the unit?
Can you here the radio in the vehicle?
Have you tried adjusting the rear radio volume control?
Wrong siren tone Two-Tone option installed
Aux Input set to wrong function
Is the T-T option selected?
Is the SWP option selected?
Phaser or Horn
not working
Tone disabled Is the P_I option selected?
Is the H_I option selected?
Automatic Siren
not working
Automatic Siren disabled Is the AUT_S option selected properly?
Lever switch not
working at all
No power to lever switch
No ground at siren connector
Do the lever switch indicators light?
Does the siren work?
Lever switch not
working in some
positions
Loose lever switch output connec-
tion
Does the lever switch indicator work in those positions?
Is the corresponding fuse blown?
Aux control switch
not working
No power to aux switches
Loose aux switch output connection
Do the aux switch indicators light?
Is the corresponding fuse blown?
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