Parasound A 51 manual Troubleshooting Guide, Trouble Probable Cause Remedy

TROUBLESHOOTING GUIDE 11

TROUBLE	PROBABLE CAUSE	REMEDY
No power	Power cord is disconnected	Connect power cord
	Auto Turn On selector switch	Check for correct position of the Auto
	is in wrong position	Turn On switch
	AC fuse blown	Replace with same value fuse
Auto turn on doesn’t	DC trigger source wired in	Check polarity of DC source with a voltmeter.
function with a trigger	reverse or voltage too low	Try connecting a 9V battery to the 12V DC input
voltage
	Auto Turn On selector switch	Make sure Auto Turn On selector switch is
	is in wrong position	in its 12V position
Auto turn on doesn’t	Auto Turn On selector switch	Make sure Auto Turn On selector switch is
function with an audio	is in wrong position	in its Audio position
input signal
	Sensitivity incorrectly adjusted	Turn the Audio trigger Sensitivity knob
		counterclockwise
A 51 will not turn off when	Sensitivity level too high	Turn Sensitivity knob clockwise toward 250 mV
audio signal is removed
Power on, but no sound	Bad connection from surround	Check input connections or try a different
	controller	set of cables
On-Off button glows red	Over-current protection circuitry	Check speaker load impedance. Check speaker
and channel indicator(s)	has been activated- one or both	wires and connections
off	blue channel LEDs not illuminated
	A 51 has overheated - red Hi	Allow A 51 to cool. Check that there is adequate
	Temp indicator is on	ventilation around the A 51. Be sure the load
		impedance of each channel is no less than 4 ohms
Distorted sound	Damaged speaker	Connect each speaker to another channel on the
		A 51. If the same speaker remains distorted, the
		speaker or its wire is damaged. If the other speak-
		er distorts, the problem may be with the A 51, the
		surround controller, or a source component
	Problem with preamplifier	Switch the input cables. If distortion moves
	or source component	to another channel, the problem is with a
		component other than the A 51
	Balanced-Unbalanced Input	Move to the correct position for the jacks
	switch is in the incorrect position	in use
Hum and / or buzz	Ground loop between surround	Move the Ground switch to its Lift position.
through speakers	controller and A 51 or at the	Install nylon shoulder washers on both sides
	equipment rack	of the panels of all equipment to insulate metal
		from touching the rack
	Ground loop from cable TV	Move the Ground switch to its Lift position.
		Install a cable isolation device such as the
		Xantech 634 Ground Breaker.
		www.xantech.com
	Other ground loop	Contact Parasound Technical Service
A 51 is overheating	Load impedance at speaker	Make sure the speaker or speaker selector
	terminals is too low	load is 4 ohms or higher
	Not enough ventilation	Make sure the A 51 has adequate ventilation