QSC ISA 300T User Manual Download Page 33

INDICATION: CLIP LED FLASHING

• If the red clip

 

indicator flashes when signal is applied, the amplifier output may be shorted. Check that the speaker cable connec-

tions are tight and reliable at both ends. Check the speaker cables for stray strands or breaks in the insulation. Trim off all loose
strands of wire and insulate any exposed wire with electrical tape. All connections should be made with great care and all wire
terminations should be carefully checked to ensure quality workmanship.

• If the red clip

 

indicator flashes when connecting the speaker cable between the + and - terminals, then that speaker cable (or

speaker) may be shorted. Check the cable and the speaker.

TROUBLESHOOTING:

 NO SOUND

Problem: NO SOUND

• INDICATION: POWER LED INDICATOR NOT ILLUMINATED

• Check  both ends of the AC line cord for proper connection. Both ends should be fully seated in their connectors.

• Check that the AC outlet works by plugging in a known-good device or by testing with a voltmeter. If too many amplifiers are used on

one outlet, the building's circuit breaker may trip and shut off power. If this is the case, unplug some of the amplifiers from the outlet,
reset the building’s breaker and try again. For the other amps, use an outlet that is connected to another circuit breaker to distribute
the load current.

• Check the rear panel circuit breaker on the amplifier. It should not have its white colored “trip” indicator showing. If it does, reset the

breaker by pushing the indicator back in until it clicks and locks inward.

• An amplifier which keeps tripping its circuit breaker may have a serious internal fault. Turn it off, remove AC power, and have the

amplifier serviced by a qualified technician.

INDICATION: SIGNAL LED’S NOT RESPONDING TO INPUT SIGNAL LEVEL (NOT LIGHTING)

• If the green power

 

indicator LED is lit, but the signal LEDs do not light up at all, check the input. Make sure the signal source is

working and try another input cable. Connect the source to another channel or amplifier to check that it is working.

•  If you are using the XLR or terminal block inputs, be sure the connectors are fully inserted at both ends of all interconnecting cables.

If you are using the DataPort for your input signal, ensure the DataPort cable is properly connected at both ends and that the device
supplying the audio signal to the DataPort is properly configured.

INDICATION: SIGNAL LEDS RESPONDING TO SIGNAL LEVEL

• If the green signal LED indicators are lighting normally, the fault is somewhere between the amp and the speakers. Check the speaker

wiring for breaks. Check for proper connection at each end. Try another speaker and cable, if necessary. If your system has multiple
speakers connected in series, any one speaker failure will cause all other speakers (in the same series circuit) to loose their signal.

INDICATION: CLIP LEDS BRIGHT AND STEADY

The amplifier is in protective muting.

• Three seconds or so of muting is normal when the amp is turned on. After power-up muting, the clip LED should go out.

• Overheating will cause protective muting and the clip LED to fully illuminate. If the amp is overheated, the fan will be running at full

speed and the chassis will be very warm to the touch; sound should resume within a minute as the amplifier cools to a safe
operating temperature. DO NOT TURN THE AMP OFF! This would stop the fan from cooling the inside of the amplifier. Instead,
reduce the input signal ( or amp gain setting) and wait for the amp to resume operation automatically.

• Check for proper ventilation. If the fan isn't running at all, the amplifier requires servicing.

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Summary of Contents for ISA 300T

Page 1: ...User Manual ISA Audio Power Amplifiers ISA Series Installed Sound Amplifiers TD 000093 00 rev C TD 000093 00 n ISA 300T n ISA 500T n ISA 800T n ISA 280 n ISA 450 n ISA 750...

Page 2: ...ts Inc QSC is a registered trademark of QSC Audio Products Inc QSC and the QSC logo are registered with the U S Patent and Trademark Office The Audio Precision logo is the property of Audio Precision...

Page 3: ...ower 17 CONNECTIONS Inputs XLR and Terminal Block Input Jacks 18 Inputs DataPort V2 Connections and Notes 19 Outputs Using the Screw Terminal Connections 20 Outputs Direct Low Impedance 2 16 ohm loads...

Page 4: ...nitoring a DataPort V2 version 2 is included on all ISA models Consult your QSC representative for accessory compatibility information The ISA amplifiers are easy to use All operating mode switches ar...

Page 5: ...nt 8 Output Connections Low Impedance REAR PANEL ISA 300T ISA 500T ISA 800T 1 Gain Controls 2 Terminal Block Inputs 3 DataPort V2 Connector 4 XLR Inputs 5 Mode Switches 6 Mode Switch Configuration Cha...

Page 6: ...nel serial number label then the amplifier requires servicing Keep the inlet and exhaust air vents clear of any obstructions Insure that the air exhausted from the vents has an exit from the equipment...

Page 7: ...is normal but indicates that the input signal strength should be increased Occasional illumination normal for weak input signal strength Illuminated dimly all the time with brighter flashing normal f...

Page 8: ...he Gain controls are power levels not voltage To have an idea of the approximate output power the table at left provides the output power by model as a function of the Gain setting The data provided i...

Page 9: ...n I Connect to the DataPort V2 Consult your QSC representative for up to date accessory compatibility QSC has several DataPort based accessories available like the DSP 3 Digital Signal Processing Modu...

Page 10: ...IP switches for PARALLEL mode see facing page 2 Connect the one input signal to any one input connector 3 Connect the two speakers one to CH1 s output terminals one to CH2 s output terminals STEREO Ea...

Page 11: ...setting keys for each mode at the right These keys are printed on the amplifier s rear panel for easy reference when you are behind the equipment rack ISA 280 ISA 450 and ISA 750 mode switches ISA 30...

Page 12: ...1 Set the DIP switches for bridge mode see below 2 Connect the one input signal to CH1 s input XLR or terminal block 3 Connect the one speaker load to the bridge output terminals 4 Use channel 1 s gai...

Page 13: ...switch The frequency is determined by the frequency selection DIP switch There is a 5 hertz roll off in the filter off position to protect the speaker loads from sub audio or DC signals The off posit...

Page 14: ...00T ISA 800T Note There is no Filter OFF selection on T models Frequency response curve for ISA 280 ISA 450 ISA 750 5 0 h e r t z s e l e c t i o n 7 5 h e r t z s e l e c t i o n F i l t e r O N 7 0...

Page 15: ...ipping There is a switchable clip limiter provided for each channel CLIP LIMITER selection switches all models Note In BRIDGE mode channel 2 s CLIP LIMITER must be placed in the OFF position for prope...

Page 16: ...er Supporting the amplifier at the rear is extremely important especially for mobile and portable use Equipment is often installed in racks at a remote location then later transported to the installat...

Page 17: ...the exhaust air from the front of the amplifier is not obstructed by an equipment cabinet door or otherwise Connect the AC line cord after the amplifier has been installed in the equipment rack The I...

Page 18: ...chained to additional amplifiers Balanced connection is recommended Balanced signals are less prone to AC hum and other electrical noise Unbalanced signals can be suitable for short cable runs The sig...

Page 19: ...uts may be used for daisy chaining the DataPort V2 input signal to other amplifiers The signal level available from the unused inputs will be about 10 dB lower than the signal applied at the DataPort...

Page 20: ...y swinging it over the connections and pressing it toward the amplifier If you wiring job is messy you may need to loosen and reposition some cables to get a good fit for the cover 1 Protective cover...

Page 21: ...inal output connections The ISA 280 ISA 450 and ISA 750 provide low impedance outputs only 2 to 16 ohms while the ISA 300T ISA 500T and ISA 800T provide both low impedance and high impedance 25V 70V a...

Page 22: ...class 1 wiring must be used 25 Volt Stereo or Parallel Connection 70 Volt Stereo or Parallel Connection 100 Volt Stereo or Parallel Connection 70 volt lines Connect one of the 70 volt lines to the CH...

Page 23: ...BRIDGE CONNECTION TO DISTRIBUTED OUTPUTS 200 Volt Bridge Connection 140 Volt Bridge Connection 200 volt line Connect the 200 volt line between the CH1 100 terminal and the CH2 100 terminal Note that...

Page 24: ...r then any of the rated low impedance load values can be connected at the low impedance terminals For applications where the high impedance output power is 20 50 then 8 or 16 ohm loads on the low impe...

Page 25: ...l wiring tie down points stamped into the steel chassis When used properly they will help keep your connections reliable Securing the wires to the tie down tabs will keep the stress of wire movement a...

Page 26: ...ations A NOTE ON SOUND PRESSURE LEVELS Sound is heard as the ear converts vibration from sound waves into impulses in the nerves of the ear Sounds above 90 decibels particularly if the sound is prolon...

Page 27: ...dance requirements It is reliable because the parallel connection scheme makes it so that if any one speaker fails the remaining speakers will continue to operate Additionally since the operating volt...

Page 28: ...his will cause an additional layer of hash in the clipping and will also result in audible clicking noises from the transformers inside the amplifier These symptoms indicate abnormal stress and should...

Page 29: ...mber 22 29 APPLICATIONS DISTRIBUTED OUTPUTS 70 Volt two zone example The illustration to the right shows a typical two zone 70 volt system When using 70 volt speaker loads make sure that connections t...

Page 30: ...ot often with speaker cabinets for wiring conve nience The exposed speaker connections make this method easy for small strings of speakers in one area Most PA type Multiple Lo Z Loads in Series 30 spe...

Page 31: ...ixing and matching speaker loads of varying impedances no damage to the amplifier will result as long as the total impedance is within 2 to 16 ohms per channel Most PA type speaker cabinets are provid...

Page 32: ...ible low frequency noise The LF 3 Low Frequency Filter is a new module for tri amp applications The LF 3 provides low frequency bandpass filters for each amp channel and is used in conjunction with XC...

Page 33: ...nician INDICATION SIGNAL LED S NOT RESPONDING TO INPUT SIGNAL LEVEL NOT LIGHTING If the green power indicator LED is lit but the signal LEDs do not light up at all check the input Make sure the signal...

Page 34: ...in the system then avoid those spots Cables with faulty shielding are a common entry point for hum Use top quality cabling Another common source of magnetic fields are wall warts or pluggable transfo...

Page 35: ...kHz 1 THD 830 1400 2400 DYNAMIC HEADROOM all models 2 dB at 4 ohms DISTORTION SMPTE IM all models LESS THAN 0 01 LESS THAN 0 01 LESS THAN 0 01 FREQUENCY RESPONSE all models 20 Hz to 20 kHz 0 1 dB at 1...

Page 36: ...TYPE AB AB Class H POWER REQUIREMENTS SEE SERIAL NUMBER LABEL ON REAR PANEL FOR THE SPECIFIED OPERATING VOLTAGE POWER CONSUMPTION 120 VAC typical both channels driven Idle 0 3 0 4 0 5 1 8 power 8 ohms...

Page 37: ...er channel 300 500 800 100 volt 300 500 800 140 volt bridge 600 1000 1600 200 volt bridge 600 1000 1600 DYNAMIC HEADROOM all models 2 dB at 4 ohms DISTORTION SMPTE IM all models LESS THAN 0 01 LESS TH...

Page 38: ...models SEE SERIAL NUMBER LABEL ON REAR PANEL FOR THE SPECIFIED OPERATING VOLTAGE CURRENT CONSUMPTION 120 VAC typical both channels driven in Amperes Idle 0 3 0 4 0 5 1 8 power 8 ohms 2 6 3 5 4 5 1 8...

Page 39: ...Postanschrift Direcci n postal QSC Audio Products Inc 1675 MacArthur Boulevard Costa Mesa CA 92626 1468 USA Telephone Numbers Num ros de t l phone Telefonnummern N meros de tel fono Main Number Num r...

Page 40: ...QSC Audio Products Inc 1675 MacArthur Boulevard Costa Mesa California 92626 USA QSC and the QSC logo are registered with the U S Patent and Trademark Office 2000 QSC Audio Products Inc...

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