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 | |
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| 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 |
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Auto Turn On selector switch in | Make sure Auto Turn On selector switch | ||
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| wrong position | is in its 12V position | |
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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 | |
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| knob counterclockwise | |
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A 21 will not turn off when | Sensitivity level too high | Turn Sensitivity knob clockwise toward 200 mV | |
audio signal is removed |
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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 | ||
and channel indicator(s) off | controller | different set of cables | |
Check speaker load impedance. Check speaker | |||
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| been activated- one or both blue | wires and connections | |
| channel LEDs not illuminated |
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| 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 | |
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| impedance of each channel is no less than 4 Ω | |
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Distorted sound | Damaged speaker | Connect each speaker to the opposite channel | |
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| on the A 21. If the same speaker remains distorted, | |
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| the speaker or its wire is damaged. If the other | |
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| speaker distorts, the problem may be with the | |
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| A 21, the preamp, or a source component | |
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| Problem with preamplifier or source | Switch the left and right input cables. If | |
| component | distortion moves to the other channel, the | |
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| problem is with a component other than the A 21 | |
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| Move to the correct position for the | ||
| is in the incorrect position | jack in use | |
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| Mono Bridge switch is in the Mono | Move switch to its Stereo position | |
| bridged position |
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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 | |
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| the panels of all equipment to insulate metal | |
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| from touching the rack | |
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| Ground loop from cable TV | Move the Ground switch to its Lift position. | |
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| Install cable isolation device such as the | |
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| Xantech 634 Ground Breaker | |
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| www.xantech.com | |
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| 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 | |
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| Not enough ventilation | Make sure the A 21 has adequate ventilation | |
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