QSC GX3 User Manual download pdf (Page 10)

TROUBLESHOOTING

NO POWER, NO LIGHTS, NO FAN

Conrm that the AC cord is fully seated and connected to a

live outlet. Check the AC source by trying another device

such as a lamp. Check the BREAKER on the back of the

amplier by pushing in the button. If the breaker trips off

quickly, the amplier needs servicing.

AMPLIFIER LOSES VOLUME

If the amplier is worked too hard, GuardRail™ will

reduce volume to prevent thermal muting. The fan should be

running at full speed. Reduce input signal somewhat and the

amp should return to normal gain within 1-2 minutes. If the

amp feels hot and the fan is not running, it needs to be

serviced.

CHANNEL 1 PRODUCES DEEP BASS ONLY.

Check the position of the CROSSOVER switch on the rear

panel. Set on FULL RANGE for normal, independent use of

each channel.

CHANNEL 2 INPUT SEEMS DEAD.

Check the position of the CROSSOVER switch on the rear

panel. Set on FULL RANGE for normal, independent use of

each channel.

AMPLIFIER SOUNDS DISTORTED.

If the red CLIP LED is ashing, the amplier is being played

beyond its normal rated power. GuardRail™ circuitry will reduce

volume somewhat to prevent severe overdrive, but if the input

signal is further increased, the limiter can be overridden, with

increased distortion.

If the speakers or speaker cables are shorted or defective,

the amplier may distort at lower-than-normal levels, with

increased ashing of the red CLIP LED. This should be

checked by trying an alternate speaker and cable.

If too many speakers are connected to each channel

(impedance below 4 ohms), the amp will overload more

easily and will probably run hot.

If the sound is distorted or garbled without ashing the red

CLIP LED, the distortion is not occurring inside the amplier.

Either the speaker is bad or the input signal is distorted.

• Conrm that the speaker is OK by trying a different unit.

• Input overload can occur if the amplier Gain controls are set

too low, and the input source is overdriven to compensate

Reduce the source volume until the distortion clears up, and

increase amp Gain to reach the desired level. It is generally

desireable to keep the amp gains at or near their full,

clockwise, position.

• Check all input connections. Do not plug two different sources

into the same channel. Use a mixer to blend sources.

NO SOUND, WITH BLUE LED ONLY, NO GREEN OR

RED LED

Conrm that the Gain controls are turned up. Conrm that

the input cables are correctly installed at both ends. If using

1/4-inch speaker cables, do not confuse with input cables.

Conrm that the source is active. If necessary, try another

source, or connect another amplier to the existing source.

NO SOUND, BUT THE GREEN LED IS RESPONDING

The green LED indicates the amp is producing a signal, so

sound should be heard if the speaker is connected. Check

the speaker connections at both ends, and try a different

speaker.

NO SOUND, RED LED ON

The amp mutes briey when turned on and off to prevent

thumps. If the amp overheats severely, it will mute until it cools

off. The fan will be running at full speed, and sound should

resume in less than a minute. If the amp feels hot and the fan

is not running, it needs to be serviced.

BACKGROUND HUM

Balanced XLR or TRS cables are better for long runs. Hum can

be a problem when connecting to TV-cable rigs, since the TV

cable often creates a ground conict. Request or install a TV-

cable isolator to reduce this problem.

Hum can also occur earlier in the signal chain, depending on the

types of connections. It often helps to plug everything into the

same AC strip, if the total power consumption is not excessive.

As a last resort, mild hum can sometimes be reduced by

lowering the amp gain, and increasing the source gain to

compensate, but you must ensure that the source can deliver

the extra volume without overload distortion. If this does not

reduce hum, it is coming from the source.

AMPLIFIER NEEDS SERVICING

The following conditions indicate possible unsafe conditions

that require service before using. If observed, unplug the AC

cord from the wall and when safe, remove the amp for

servicing.

• If the amplier emits smoke or burning smells

• If the case is severely dented or deformed

• If the amplier is soaked with any uid

• If internal parts sound loose

• If the AC breaker trips when power is applied

• If the amplier is dropped, carefully inspect for damage or

loose parts before attempting to use.

TROUBLESHOOTING

1 2 ... 5 6 7 8 9 10 11 12 13 14 15 ... 59 60

Comments to this Manuals

No comments

QSC GX3 User Manual Page 10

Comments to this Manuals

Related products and manuals for Audio amplifiers QSC GX3