3M 478DA (D-15) manual Printed on 50% recycled paper

Technician Troubleshooting Guide			Model 481BA (D-20)
	Problem	Possible Cause	Correction
￿	The VEHICLE Indicator	Defective call switch.	Check and replace call
	Light (yellow) is OFF and the		switch.
	vehicle detection tone does
	not sound.
		Defective analog or logic	Check and replace analog or
		board.	logic board.
￿	Unit will not return to standby	Defective logic board.	Check and replace logic
	mode when STANDBY		board.
	Switch is pressed.
￿	Unit will not come out of	Defective logic board.	Check and replace logic
	standby mode.		board.
￿	Outbound audio distorted.	Defective analog board.	Check and replace analog
			board.
		Defective internal	Replace microphone.
		microphone.
		Defective outside speaker.	Replace speaker.

￿

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Printed on 50% recycled paper,	© 3M 1997 January
	78-6912-0634-2 Rev. A
including 10% post-consumer waste.