QSC-CX12T-pwr-sm 维修电路原理图.pdf

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1、CX SeriesCX4CX12RadioFans.CN 收音机爱 好者资料库CX SeriesCX4TCX1 2TRadioFans.CN 收音机爱 好者资料库CX SERIES AMPLIFIERSERVICE MANUALCX4 - CX4TCX6 - CX6TCX12 - CX12TQSC Technical ServicesWats: 1-800-772-2834Local: 1- 714- 957- 7150Fax: 1-714-754-6173QSC Online!Online Computer Information System1- 800- 856- 6003I- 71 4

2、- 668- 7567QSC Audio Products, Inc.1675 MacArthur Blvd.Costa Mesa, CA 92626http:/CX Series Chassis DrawingsCX4 Chassis Assembly .42CX4T Chassis Assembly .45CX6 &CX12 Chassis Assembly y .48CX6T &CX12T Chassis Assembly y.48CX 4 / 4TDisplay Board Schematic .39CX 6T & 12T Display Board Schematic .39CX4

3、/4T Series Main Amplifier Board .40CX6 /6T Series Main Amplifier Board .41CX12 /12T Series Main Amplifier Board .42CX Series Wiring DiagramsCX4 Wiring Diagram (120v) ).56CX4 Wiring Diagram (100v) ).57CX4 Wiring Diagram (230v) ).58CX4T Wiring Diagram (120v) ).59CX4T Wiring Diagram (100v) ).60CX4T Wir

4、ing Diagram (230v) ).61CX6 Wiring Diagram (120v) ).62CX6 Wiring Diagram (100v) ).63CX6 Wiring Diagram (230v).64CX6T Wiring Diagram (120v) ).65CX6T Wiring Diagram (100v).66CX6T Wiring Diagram (230v).67CX12 Wiring Diagram (120v).68CX12 Wiring Diagram(100v) ).69CX12 Wiring Diagram (230v) ).70CX12T Wiri

5、ng Diagram (120v).71CX12T Wiring Diagram (100v) ).72CX12T Wiring Diagram (230v) ).73.e.a- - 2- ww.,_- CX Series*- “- ” *“arTCX Series Product SpecificationsCX6cx4CX12Output Power (per channel):Continuous Average Output Power both channels driven:8ohms,20Hz- 20kHz, 0.1%THD 150watts4ohms,20Hz- 20kHz,

6、0.1%THD 225watts2ohms,1kHz ,1% THD* 350wattsContinuous Average Output Power bridged mono oDeration:8 ohms, 20Hz - 20kHz, 0.1% THD4 ohms, 1 kHz, 1% THD*Voltage Gain ( direct outputs):Sensitivity (for rated power 8 ohms):Distortion:SMPTE- IMFrequency Response:Damping Factor ( direct outputs):Noise:Inp

7、ut ImpedanceDimensionsFaceplate WidthFaceplate HeightChassis DepthWeightShipping, Lbs/kgNet, Lbs/kg450 watts700 watts35x (31 dB)0.96 V rms200watts 400 watts300watts 650watts450 0watts 650watts600 watts400 watts40 x (32 dB)1 .02 Vrms1200 watts1800 watts56.5 (35 dB)1 .00 VrmsLess than 0.05%20Hz to 20k

8、Hz, +/-0.2dB2001 00dB below rated output (20 Hz to 20 kHz)10k unbalanced, 20k balancedStandard 19” Rack Mounting3.5” (13.3 cm) 5.25” (13.3 cm)17.9” (45.5 cm) 17.9” (45.5 cm)36/16.453/2430/13.644/205.25” (13.3 cm)17.9” (45.5 cm)58/26.350122.7CX Series Product SpecificationsCX SeriesCX4 TCX12TCX4TOutp

9、ut Power (per channel):Direct Output, watts per channel, both channels driven:8 ohms, 45H.z - 20kHz, 0.1% THD 150 watts4 ohms, 45Hz - 20kHz, 0.1% THD 225 watts2 ohms, 1 kHz, 1% THD* 350 wattsIsolated outputs, watts per channel, both channels driven:70V or 100V, 45Hz- 16kHz, 0.25% THD70V or 100V, 1 k

10、Hz, 0.1% THD 175 watts25V, 45Hz- 16kHz, 0.25% THD25V, 1 kHz, 0.1% THD 150 wattsDirect Outputs, bridged mono:8 ohms, 45 Hz-20kHz, 0.1% THD 450 watts4 ohms, 1kHz, 1% THD 700 wattsCX6T200 watts300 watts450 watts250 watts250 watts600 watts900 wattsCX12T400 watts600 watts900 watts500 watts500 watts1200 w

11、atts1800 wattsVoltage Gain (dB):Sensitivity (for rated power 8 ohms)Distortion:SMPTE- IMFrequency Response:Damping Factor:Noise:Input ImpedanceDimensionsFaceplate WidthFaceplate HeightChassis DepthWeightShipping, Lbs/kgNet, Lbs/kg35x (31 dB)40 x (32 dB)0.98 V rms 1.02 Vrms56.5x (35 dB)1 .00 VrmsLess

12、 than 0.05%- 3dB 45Hz*, - 0.2dB 20kHz ; direct outputs45Hz* - 16kHz, +0, 3dB ; isolated outputs*Low Frequency is limited by 18 dB/octave 45 Hz high pass filter200 ( direct outputs)1 00dB below rated output (20 Hz to 20 kHz)10k ohms unbalanced and 20k balancedStandard 19” Rack Mounting3.5” (13.3 cm)

13、5.25” (13.3 cm)17.9” (45.5 cm) 17.9” (45.5 cm)46/2162/2840/18.255/255.25” (13.3 cm)17.9” (45.5 cm)75/3467/30.4CX SeriesI n t r o d u c t i o nThis manual is prepared to assist service personnel with the repair and calibration of theCX Series power amplifiers The procedures described in this manual r

14、equire advancedtechnical experience and sophisticated audio test equipment.AACAUTION: To reduce the risk of electric shock, do not remove the cover. No user-serviceable parts inside. Refer servicing to qualified service personnel.WARNING: To prevent fire or electric shock, do not expose this equipme

15、nt to rainor moisture.DocumentationThis manual contains schematics, printed circuit board (PCB) drawings, parts lists, andmechanical assembly drawings. This information should be used in conjunction with the test andtroubleshooting guide.The electrical and electronic components are identified by cir

16、cuit identification numbers on theschematics and the parts list, The test & troubleshooting sections refer to designations shown inthe schematics.Equivalent PartsAlthough many of the electronic components used in this product may be available fromelectronic suppliers, some components are specially t

17、ested and approved by QSC. A productrepaired with non-QSC supplied components may not meet factory specifications. Repairsperformed using non-QSC parts may void the product warranty, When in doubt, you may contactQSC Technical Services for assistance.Parts orders to QSC should include the product mo

18、del number, the part description, and the QSCpart number (from the parts list in this manual). Parts will be shipped via UPS, F.O.B. Costa Mesa,California, Shipping, handling and COD charges may be added to the cost of the parts.Factory RepairIt may become necessary to return a product to the factor

19、y for repair. Call QSC TechnicalServices for return instructions. You must obtain a Return Authorization number from QSC beforereturning a product to the factory. QSC Technical Services may be reached at (800) 772- 2834.3CX SeriesTest EquipmentFor testing, as outlined in this manual, the following e

20、quipment will be needed.REQUIRED TEST EQUIPMENT SUGGESTED TEST EQUIPMENT- Distortion Analyzer capable of 0.05% THD+N * Audio Precision System One- High Power Load Bank (8, 4, & 2 ohms) for CX - Thermocouple probe- High Power Load Bank (40,20, & 10 ohms) for CX T- Function Generator- 20MHz Oscillosco

21、pe- Digital Multimeter- Variac (0- l 40 VAC, 20- 30A)Audio Precision test and procedures files are made available, free of charge, from QSC TechnicalServices by either sending a self addressed stamped envelope and a 3 1/2” disk to QSC, or bylogging on to QSC Online and downloading the appropriate fi

22、les.Test Point ScheduleThe following test points are described for testing and troubleshooting references. These testpoints are universal among all models. Actual voltages and current readings will vary.AMPLIFIER SECTIONJ502 Bed of Nails (J602 is for channel 2):Pin 1 Negative 15VDC IC Supply,Pin 2 P

23、ositive 15VDC IC Supply.Pin 3 No ConnectionPin 4 Second Stage OpAmp.Less than 1 00mVDC offset.Pin 5 No ConnectionPin 6 Positive Switched Bus Rail.Test signal superimposed on DC voltages.Pin 7 No Connection.Pin 8 Negative Switched Bus Rail.Test signal superimposed on DC voltages.T e s t & Calibration

24、NOTE: This test procedure will refer to the amplifiers channels as Ch 1 (Channel 1) & Ch2(Channel 2).Component designation will have the prefix “5” for Ch 1 and “6” for Ch2.CX4 / CX4T Test Procedurel S E T -U P1. Connect a test load to the output terminals of the amplifier.2. Make sure the Stereo /

25、Bridge switch is set to the Stereo position.3. Connect a distortion analyzer with a resolution of 0.05%, 20- 20kHz (or better) to the outputterminals of the amplifier. Enable the 80kHz low pass filter.4. Connect a dual-channel oscilloscope to the following test points:Ch1 - a 10X (vertical sensitivi

26、ty - 2V/cm) scope probe to the channel speaker output.Ch2 - a 1X scope probe (vertical sensitivity - 0.1V/cm) to the distortion analyzeroutput.5. Set amp gain pots fully clockwise and turn on power switch.6. Connect the output of the signal generator to the input terminals of the amplifier and selec

27、tan output of 0.96 (0.98 for CX4T) VRMS, 1 KHz sine wave.7. Plug the amplifier in to a variac and set up an AC line current monitor.l POWER UP & MUTE DELAY TEST1. Slowly raise the variac voltage and watch for excessive current draw (Line current greaterthan 0.5A a.c. at 60 Volts). This is slightly l

28、ess for 240V. Pause at 90VAC (200VACEuropean) for three seconds until the mute / protect circuit disengages. Continue to 120VAC(240V European).2. Turn the power switch off and on a few times to verify the 1 - 3 second power- up mutingdelay. Check both channels.l CHANNEL OUTPUT1. Look for amplified s

29、ignal on the scope for channel 1. Switch the input signal and scope tochannel 2 and repeat output test. Check for noisy / contaminated gain pots by observinggeneral instability on the distortion waveform while adjusting the gain control levels.2. Select an 8 ohm load and confirm with the gain contro

30、ls that this amplifier is producing aminimum of 170 watts at 1 kHz just beyond the point of clipping (1 .0% THD+N). Check bothchannels.l BIAS ADJUSTMENT1. Let the amplifier cool down to room temperature.2. With an input amplitude of 1Vrms increase the input frequency to 15kHz. Reduce the inputsignal

31、 20dB (80%) from full output. For the first channel to be calibrated, adjust the crossovertrimpot R512 for about a 400mVpk-pk crossover spike protruding from the noise trace onthe oscilloscope. It will be necessary to have the oscilloscope measure unfiltered distortionCX Seriesfrom the amplifier in

32、order to see the crossover spike. It is necessary to disable the 80kHzlowpass filter on the analyzer for this test. Further trim R512 so that the total distortion forthat channel is at about 0.1% THD+N. If bias is not adjustable, see the bias description andtroubleshooting section of this manual,3.

33、If a distortion analyzer is not available, a less accurate crossover distortion and bias adjustmentcan be made by monitoring the driver transistor (Q503 & 0504) bias current. With theamplifier at room temperature, and with no input signal plugged into the amplifier, measure theDC voltage across the

34、emitter resistors of 0502 or Q504 (R516, R517). Adjust R512 toobtain about 80mV d.c. across one of these resistors.4. With no signal plugged into the amplifier and with an 8 ohm load, verify that the AC idlecurrent from the AC service is no more than 1 .O amps a.c.5. Let the amplifier cool down and

35、check / adjust channel 2.l SHORT CIRCUIT CURRENT1. Select a 4 ohm load and apply a 1Vrms sinewave (1 kHz) input signal to both channels of theamplifier. Ensure that power is on and that the gain controls are fully up.2. While the amplifier is producing power into the loads, apply a short to the outp

36、ut binding postsof each channel. In other words, apply a jumper between the red and black binding posts ofeach channel. Once this is done, the combined AC line current draw for both channelsshould be no greater than 7.5A ac. This is with a 120 volt AC service to the amplifier. Currentmay be lower as

37、 AC line voltage is lower. As the amplifer heats up, current draw may increaseto about 9 amperes until thermal protect shutdown.3. While the amplifier is driving a short, observe the main supply rail voltages. Ideally, they will beno more than 3 volts from each other.4. Remove the short from each ch

38、annel and verify that the channels recover in to 4 ohm loads.The output should not experience any hang up and a full sinewave should be present just asit was before a short was applied for this test.5. If the amplifier does not pass any of the above steps, follow the proceeding steps. If steps 2,3,

39、and 4 above pass, continue to the next test FREQUENCY RESPONSE.Setting Short Circuit Current Limitsa. Select a 4 ohm load and apply a 1.2Vrms sinewave (1 kHz) input signal to bothchannels of the amplifier. Ensure that power is on and that the gain controls arefully up.b. Turn gain controls on CH2 fu

40、lly down. CH1 should be producing max power in the4 ohm load.c. While CH1 is delivering power into the load, apply a short across channel 1sbinding posts.d. Observe that the A.C. current draw is between 2.5 to 3.5 amps A.C. Adjust R514and R515 to get this current reading if your initial reading is o

41、ff. R514 is thepositive current limit adjust and R515 is the negative current limit adjust Adjustboth channels the same for a change in current limiting. Both wipers need toadjust evenly to achieve a balanced setting.e. Once the correct AC current draw is set, remove the short from the output Whenth

42、is is done, the output power should spring back into the 4 ohm load. If it doesnot, the current limits are set too low.f, Once the output recovers into the 4 ohm load, verify that both polarities of theoutput sinewave are clipping at the same time. If one polarity clips before the other,adjust the c

43、urrent limit for that polarity (I + or I - ) until both polarities clip at thesame time.g. After the short circuit current is set and even clipping is achieved, re- apply the shortto the output to reconfirm AC line current. If the current draw is not within therange specified, again balance the curr

44、ent limit trimpots until even clipping and thecorrect AC current draw is met.h. Remove the input signal from CH1 and calibrate CH2. It is important to calibrateonly one channel at a time.l FREQUENCY RESPONSEC X1. Set load to 8 ohms and scale the input generator to gain 1 watt of power from the ampli

45、fier oneach channel. Gain controls on the amplifier should be fully up.2. Check frequency response from 20Hz to 20kHz (+/- 0.2dB) by sweeping random frequenciesbetween these extremes. This is done by verifying the same voltage amplitude at each ofthe frequencies selected (within 20Hz to 20kH.z). Che

46、ck both channels,CXT1. Set load to 8 ohms and scale the input generator to gain 1 watt of power from the amplifier oneach channel. Gain controls on the amplifier should be fully up.2. Check frequency response from 45Hz to 16kHz (+/- 0.2dB) by sweeping random frequenciesbetween these extremes. This i

47、s done by verifying the same voltage amplitude at each ofthe frequencies selected (within 45Hz to 16kHz). Check both channels.l POWER vs. DISTORTION TESTCX1. Check to ensure that both channels will produce rated power at 20Hz, 2KHz, and 20kHz. intoan 8 ohm load.2. While verifying rated power, check

48、that at all frequencies the distortion measurement is lessthan or equal to 0.1%. To obtain this measurement, check to ensure that the 80kHz low passfilter is engaged on the analyzer.CXT1. Check to ensure that both channels will produce rated power at 45Hz, 2KHz and 16kHz. intoan 8 ohm load.2. While

49、verifying rated power, check that at all frequencies the distortion measurement is lessthan or equal to 0.1%. To obtain this measurement, check to ensure that the 80kHz low passfilter is engaged on the analyzer. Check distributed lines (70V, 100V) with 40 ohm, 20 ohm,or 10 ohm loads to ensure that b

50、oth channels will produce rated power at 45Hz, 2kHz, and16kHz.l THERMAL TEST1. Set input frequency to 1 KHz and short both channels while they are producing power into aload.2. AC line current draw should be about 7.0 - 8.0 amps for both channels. As the amplifier getshot, there will be some current