3M 478DA (D-15) manual Food Services Trade Department

Technician Troubleshooting Guide				Model 479 (D-30)
		Problem	Possible Cause	Correction
￿	No outbound audio:		Defective menu speaker,	Check and replace menu
	∙	Power Indicator Light	menu mic, or wiring.	speaker, menu mic, or wiring.
		(green) is ON.
	∙	TALK Indicator Light
		(red) is ON when TALK
		SWITCH is pressed.
			Defective analog board.	Check and replace analog
				board.
￿	With car on loop, VEHICLE		Vehicle Detect-to-Main	Adjust R6 to increase signal
	Indicator Light (yellow) is		signal too low.	level.
	ON, but vehicle detection tone
	does not sound.
			Defective analog board.	Check and replace analog
				board.
￿	With car on loop, VEHICLE		Defective logic or analog	Check and replace logic or
	Indicator Light (yellow) is		board.	analog board.
	OFF, and vehicle detection
	tone does not sound.
￿	Outbound audio distorted.		Defective analog board.	Check and replace analog
				board.
			Defective internal	Replace microphone.
			microphone.
			Defective menu sign	Replace menu sign speaker.
			speaker.

￿

Food Services Trade Department

3M Center, Building 551-1E-02 St. Paul, MN 55144-1000

Printed in U.S.A.

Printed on 50% recycled paper,© 3M 1997 January 78-6912-0637-5 Rev. A

including 10% post-consumer waste.