Vornado SC-550-10 operating instructions Service, Problems, Symptom Possible Cause Check

Page 10 of 12 SC-550-10 28 Volt Installation and Operating Instructions

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 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.

25A Fuses are required for each light control output. Adequate fuse rating is required to prevent overheating of the output connection block.

PROBLEMS

Symptom	Possible Cause	Check
No power or siren	Power switch not turned on	Does backlighting come on?
output	Bad Speaker	Do you hear a "pop" when turned on?
	Connector or connections loose	With siren on, yelp selected, listen for tone in amplifier.
	Siren fuse blown	Is an external fuse or circuit breaker used?
	Loose connection at power source	Are the power leads connected to a good buss?
No siren tone -	High Voltage Protection	The input voltage must be less than highest rating.
PA works	PA PTT button stuck	Does PTT button release properly?
	Cutout activated	Does the siren work when Cutout input is disconnected?
	Cutout Polarity Option set wrong	Is the Cutout Input Polarity option properly configured?
No PA	PA volume not set properly	Have you tried turning the PA volume control?
Distorted siren	Speaker assembly loose	Is the speaker bell or tip loose?
sound	Intermittent Aux Input connection	Is the Aux Siren Input used and wired properly?
	Low vehicle voltage	The input voltage must be greater than lowest rating.
Intermittent siren	High Voltage Protection	Is the vehicle voltage regulator working properly?
tone	Connector or connections loose	Is the connector tight on the back of the unit?
	Loose connection at power source	Check for loose leads back to power source.
	PA PTT button activation	Is something lying on the PTT button?
	Circuit breaker in supply connection	Is a circuit breaker used with at least a 50A rating?
Horn function	Siren button switch stuck	Does the Siren button switch return fully when released?
stuck on or	Aux Siren switch stuck	Does the Aux Siren switch return fully when released?
Manual or Phaser	Aux Input improperly connected	Is the Aux Siren Input used and wired properly?
stuck on	Aux Input Polarity Option set wrong	Is the AUX Siren Polarity option properly configured?
No Radio	Unit not connected to radio	Is the radio connected properly to the unit?
	Radio volume too low	Can you here the radio in the vehicle?
		Have you tried setting the Radio Volume Adjust?
Wrong siren tone	Two-Tone option selected	Is the Two-Tone option set?
Phaser not work-	Phaser disabled	Is the Phaser Disable option set?
ing
Horn not working	Horn disabled	Is the Horn Disable option set?
Manual stops	Short Manual enabled	Is the Short Manual option set?
immediately
Automatic Siren	Automatic Siren disabled	Is the Automatic Siren Disable option set?
not working
Light Output not	Light Control Output fuse blown	Is the light or device shorting?
working	Internal relay contacts bad	Is the output current limited to 20A?
Light Output stays	Internal relay contacts fused from	Is the output current limited to 20A?
on	overheating
Non-progressive	Internal switching transistor bad	Is the external relay coil shorting?
output not work-		Is the output current limited to 500mA?
ing
Slide switch	Slide Switch is reversed	Is the Slide Switch Reverse option set?
outputs turn on in
wrong order

05/07/05 CP4945A