User's Manual
TB0346A  Page 11 of 12  05/07/05 
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 internal siren fuse doesn't necessarily mean that the unit is bad. If a speaker or speaker lead is shorted this 
fuse will blow before the unit is damaged. Disconnect the SPKR leads and replace the fuse. If the unit itself emits a 
low level sound when in the Yelp position it is OK. Check the speaker(s) or leads for possible shorting. 
PROBLEMS 
Symptom Possible Cause  Check 
No Power or siren output  Power switch not turned on 
Bad Speaker 
Connector or connections loose 
Internal siren fuse blown 
Loose connection at power source 
Does backlighting come on? 
Do you hear a “pop” when turned on? 
With siren on, yelp selected, listen for tone in amplifier. 
Is an external fuse or circuit breaker used? 
Are the power leads connected to a good buss? 
No siren tone – 
PA works 
High Voltage Protection 
Mic button stuck 
Cutout activated 
Cutout Polarity Option set wrong 
The input voltage must be less than highest rating. 
Does mic button release properly? 
Does siren work when Cutout input is disconnected? 
Is the CUT P option properly configured? 
No PA  PA volume not set properly 
Selector in Radio position 
Try turning the PA volume control. 
PA is not available in the Radio position. 
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? 
The input voltage must be greater than lowest rating. 
Intermittent siren tone  High Voltage Protection 
Connector or connections loose 
Loose connection at power source 
Mic button activation 
Circuit breaker in supply 
connection 
Is the vehicle voltage regulator working properly? 
Is the connector tight on the back of the unit? 
Check for loose leads back to power source. 
Is something lying on the microphone? 
Is a circuit breaker used with at least 50A rating? 
Horn or Manual or 
Phaser stuck on 
Horn switch stuck 
Man/Phsr switch stuck 
Aux Input improperly connected 
Aux Input Polarity Option set 
wrong 
Does the Horn switch return fully when released? 
Does the Man/Phsr switch return fully when released? 
Is the Aux Input used and wired properly? 
Is the AUX P option properly configured? 
No Radio  Unit not connected to a radio 
Radio volume too low 
Is the radio connected properly to the unit? 
Can you hear the radio in the vehicle? 
Try turning the RAD volume control. 
Wrong siren tone  Two-Tone option installed. 
Aux Input set to wrong function 
Is the T-T option jumper cut? 
Is the AUX I option jumper configured properly? 
Phaser not working  Phaser disabled  Is the PHSR option jumper cut? 
Horn not working  Horn disabled  Is the trace cut that disables the Horn switch? 
Automatic Siren not 
working 
Selector in Radio position 
Automatic Siren disabled 
Siren tone is not available in Radio position. 
Is the internal red lead cut from lever switch board? 
Automatic Siren in all 
lever switch positions 
No power to red lever switch lead  Do the lever switch relays turn on devices? 
Check for power at red lever switch lead. 
Lever switch not working 
in all positions 
No power to red lever switch lead 
No ground at siren connector 
Do the lever switch indicators light? 
Check for power at red lever switch lead. 
Lever switch not working 
in some positions 
Loose lever switch output 
connection on lead 
Does the lever switch indicator light? 
Lever switch not working 
in some positions 
Loose lever switch output 
connection on lead 
Does the lever switch indicator light? 
Lever switch output 
stays on 
Internal relay contacts fused from 
overheating 
Is the output current exceeding 20AMPS? 
Rocker switch outputs 
not working 
No power to rocker switch 
Loose rocker switch output 
connection on lead 
Is the corresponding fuse blown? 
Does the rocker switch indicator light turn on? 










