Parasound A 21 manual Troubleshooting Guide, Trouble Probable Cause Remedy

13TROUBLESHOOTING GUIDE

TROUBLE	PROBABLE CAUSE	REMEDY
No power	Power cord is disconnected	Connect power cord
	Auto Turn On selector switch is in	Check for correct position of the Auto Turn On
	wrong position	switch
	AC Voltage selector switch is in the	Make sure the switch is in the
	wrong position	correct position for your region
	AC fuse blown	Replace with same value fuse
Auto turn on doesn’t	DC trigger source wired in reverse	Check polarity of DC source with a voltmeter
function with a	or voltage too low	Try connecting a 9 V battery to the 12V DC input
trigger voltage
	Auto Turn On selector switch in	Make sure Auto Turn On selector switch
	wrong position	is in its 12V position
Auto turn on doesn’t	Auto Turn On selector switch in	Make sure Auto Turn On selector switch
function with an audio	wrong position	is in its Audio position
input signal	Sensitivity incorrectly adjusted	Turn the Audio trigger Sensitivity
		knob counterclockwise
A 21 will not turn off when	Sensitivity level too high	Turn Sensitivity knob clockwise toward 200 mV
audio signal is removed
Power on, but no sound	Level controls turned too low	Turn level controls clockwise
	Bad connection from preamplifier or	Check input connections or try a
On-Off button glows red
and channel indicator(s) off	controller	different set of cables
	Over-current protection circuitry has	Check speaker load impedance. Check speaker
	been activated- one or both blue	wires and connections
	channel LEDs not illuminated
	A 21 has overheated - red Hi Temp	Allow A 21 to cool. Check that there is adequate
	indicator is on	ventilation around the A 21. Be sure the load
		impedance of each channel is no less than 4 Ω
Distorted sound	Damaged speaker	Connect each speaker to the opposite channel
		on the A 21. If the same speaker remains distorted,
		the speaker or its wire is damaged. If the other
		speaker distorts, the problem may be with the
		A 21, the preamp, or a source component
	Problem with preamplifier or source	Switch the left and right input cables. If
	component	distortion moves to the other channel, the
		problem is with a component other than the A 21
	Balanced-Unbalanced Input switch	Move to the correct position for the
	is in the incorrect position	jack in use
	Mono Bridge switch is in the Mono	Move switch to its Stereo position
	bridged position
Hum and / or buzz	Ground loop between preamplifier	Move the Ground switch to its Lift position
through speakers	and A 21 or at the equipment rack	Install nylon shoulder washers on both sides 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 cable isolation device such as the
		Xantech 634 Ground Breaker
		www.xantech.com
	Other ground loop	Contact Parasound Technical Service
A 21 is overheating	Load impedance at speaker terminals	Make sure the speaker or speaker
	is too low	selector load is 4 ohms or higher
	Not enough ventilation	Make sure the A 21 has adequate ventilation