KXR_200_Service_Manual 电路图.pdf

KXR 200 SERVICE MANUAL CONTENTS: Notices Specifications Circuit description Parts lists: Preamp PCB assembly Pwr amp PCB assembly Chassis assembly Cabinet assembly Miscellaneous Schematics/diagrams Fender Musical Instruments Corp. 7975 North Hayden Road Scottsdale, AZ 85258 RadioFans.CN 收音机爱 好者资料库 KXR 200 (This is the model name for warranty claims) SERVICE MANUAL MARCH 1996 IMPORTANT NOTICE: The information contained herein is CONFIDENTIAL and PROPRIETARY to Fender Musical Instruments Corp. It is disclosed solely for use by qualified technicians for purposes of equipment maintenance and service. It is not to be disclosed to others without the expressed permission of Fender Musical Instruments Co. All specifications subject to change without notice. For warranty repair service, only Fender specified part numbers are to be used. It is recommended they also be used for post-warranty maintenance and repair. Parts marked with an asterisk (*) indicate the required use of that specific part. This is necessary for RELIABILITY and SAFETY requirements. DO NOT USE A SUBSTITUTE! A coded naming convention is used in the description of certain parts. The codes and what they mean are as follows: CAPACITOR CODES HARDWARE CODES CAP AE=Aluminum ElectrolyticBLX=Black Oxide CAP CA=Ceramic AxialCR=Chrome Plated CAP CD=Ceramic DiskHWH=Hex Washer Head CAP MPF=Metalized Polyester FilmM=Machine Screw CAP MY=MylarNI=Nickel Plated CAP PFF=Polyester Film/FoilOHP=Oval Head Phillips PB=Particle Board RESISTOR CODESPHP=Pan Head Phillips PHPS=Pan Head Phillips Sems RES CC=Carbon CompSMA=Sheet Metal A Point RES CF=Carbon FilmSMB=Sheet Metal B Point RES FP=Flame ProofSS=Stainless Steel RES MF=Metal FilmTF=Thread Forming RES WW=Wire WoundZI=Zinc Plated RadioFans.CN 收音机爱 好者资料库 KXR 200 SPECIFICATIONS Product Release No.:PR 286 (This is not a model number) Power output:200 Watts RMS Distortion at 200 watts:Less than .1% 1kHz, below compression Less than 1% 1kHz, maximum compression Rated Load Impedance:4 Input impedance:22K Ohms Sensitivity:1.03V RMS DELTACOMP Range:20dB PREAMP SECTION: Input Impedance:XLR 1.82K Phone 18.2k Senitivity for 200 watts:XLR 2.9mV RMS Channel and masterPhone 29mV RMS Volume at maximum, all Tone controls at “0” Equalizer:For 3-band-EQ sections: +/- 12dB at 130,540 and 4200 Hz Sensitivity for channel500mV RMS (-6dBV) Inserts, Master volume At maximum setting Sensitivity for Master130mV RMS (-18dBV) Volume and FX return Control at maximum Dimensions: Height:29 3/4(75.6 cm)(w/o casters) Width: 21 11/16(55.1 cm) Depth: 12(30.5 cm) Weight:88 lbs.(40.0 kg) Product specifications are subject to change without notice RadioFans.CN 收音机爱 好者资料库 KXR 200 CIRCUIT DESCRIPTION PREAMPLIFIER Input channels 1 thru 3 will accept a balanced or unbalanced signal via a ” phone jack. Resistors R1 & R2 are precision 1% parts which maximize the Common Mode Rejection of the first opamp stage U1A.U1A provides a gain of 1, and rolls off high frequencies above 87kHz. The signal then couples to the 3 band equalizer circuit. Gyrator U2A is tuned to 130 Hz (LOW), and Gyrator U2B to 540Hz (MID). The HIGH control uses C10 and R14 to provide a 6dB per octave shelving filter above 4.2kHz. The boost/cut function is handled by U3A. The signal couples to the Volume control stage U1B. The Volume control (R17) varies the gain from less than 1 to about 23. The signal is then routed through a ribbon cable to the Channel Insert Jack J2. This 3 conductor Phone jack sends the signal out on the “Tip” contact, and accepts the return signal on the “Ring” contact. The signal then couples through C14 to the FX SEND bus, REVERB SEND bus, and MAIN bus. Although similar to channels 1 thru 3, Input channel 4 features the addition of an XLR jack which will accept a balanced low impedance microphone input. Channel 4 also features a 4-band equalizer circuit. Gyrator U11A is tuned to 125Hz (LOW), gyrator U11B is tuned to 320 Hz (LOW MID), and gyrator U12A to 1kHz (HIGH MID). The HIGH control uses C56 and R92 to provide a 6dB per octave shelving filter above 3.2 kHz. The signals from the FX SEND controls are summed at U13A, which provides a gain of 2 and drives the FX SEND jack (J10). To minimize noise, the FX RETURN jack (J11) contains a switch contact that grounds the signal line when the return jack is not being used. U13B provides a gain of less than 1 to a maximum gain of 5. The FX return signal sums with the main signal at U14A. The signals from the REVERB SEND controls are summed at U6A, which provides a gain of 2 and feeds the reverb pan drive circuit at U6B. U15A makes up the reverb recovery circuit. U15b provides variable gain and drive U14A. U14A is the summing amplifier for the Main, Effects Return, and Reverb return signals. It provides a maximum gain of about 2, feeds U14B, and drives the Line Output jacks. The Line Ouputs provide a pseudo-balanced signal. U14B feeds signal to the power amplifier. The signal form the preamp feeds from P1B pin 4, through a ribbon cable, to P1A on the power amplifier PCB. The signal couples (via C1) to the unity gain amplifier U1B. U1B contains a closed loop (gain of 1) negative feedback path, along with positive feedback through the inverting Operational Transconductance Amplifier(OTA) U2. U1B and U2 make up the gain reduction circuit for the DeltaComp clip protection feature. The attack and release circuit for the DeltaComp is made up by the Diode, Resistor, and Capacitor network which drives the Base of Q19. Comparator U1A senses the voltage from the Collectors of Q20 & Q21. When the power amplifier approaches clipping on a positive swing, the collector of Q5 pulls up R56, which turns on Q20, transferring 16vdc to the collector, pulling down R60. This causes the output (pin 1) of U1A to switch from +15vdc to 15vdc, lighting the DeltaComp/Clip LEd. Note when the DeltaComp is disabled, the Led indicates clipping of the output stage. With the DeltaComp enabled, the Led indicates an active DeltaComp circuit. The negative control voltage from R60 also feeds through P1A to P1B on the preamp PCB. The voltage is routed to the DeltaComp switch (S5A), located on the front panel. With the switch engaged, the control voltage is sent back through the ribbon cable (via P1 pin 6) to the attack/release circuit. The negative voltage drives through Diodes CR31-CR34, and charges Capacitors C16-C19 all at once in parallel as a one pole filter through a single time constant of R60 x (c16+17+18+19) or 2.2k x 8.8Uf=19.4mSec. As they charge, Q19 turns on and provides current to pin 5 of the QTA (U2). The KXR 200 DELTACOMP (CONT) current controls the output amplitude of U2. The inverted signal from U2 mixes with the input to U1B providing cancellation which reduces the input to the power amplifier. This prevents the amplifier from clipping. When the output of the power amplifier is reduced, the output of U1A toggles back to +15dvc. Due to the blocking action of Diodes CR31-CR34, Capacitors C16-C19 are forced to discharge as a 4-pole filter with different time constants through R55. R51 prevents Parasitic oscillation white Zener CR30 provides 2 slopes which results in smoother limiting. When the power amplifier approaches clipping on a negative swing, R62 is pulled low, turning on Q22 which pulls up the Base of Q21 transferring 16vdc to the collector. POWER AMPLIFIER JFET Q1 and associated components provide a 4-5 second turn-on delay for the audio input to the power amplifier. When the power is switched on, Capacitor C5 charges through Resistor R7. The negative Gate voltage pinches off the JFET, removing the ground from the input of the amplifier. When the power is switched off, C5 immediately discharges through Diode CR1, grounding the input of the amplifier. (TROUBLESHOOTING TIP) Check for proper operation of this circuit when experiencing excessive turn- on or turn off “Pops”, or no output when signal applied to the input. Many times the JFET itself can be the culprit. NOTE: Excessive turn-off “Pops” can also be caused by uneven discharge of the +/- power supplies. Usually a mismatch in the Filter Capacitors will cause this problem. Its easy to look at both supplies on an oscilloscope. Invert one scope input and check for even discharge to zero volts. Q4 is the current source for the Differential Amplifier (Q2,Q3). For the Diff amp to work properly, one half of the current from the current source must flow through each of the Diff amp legs. If the same amount of current flows through each leg of the Diff amp, the voltage drop across resistors R14 & R15 must be the same. If not, there will be a DC offset at the output of the amplifier. The overall gain of the amplifier is set up around the Diff amp. R16 (27K) is the feedback resistor and R17 (1K) is the pull down resistor. Rfb +Rpd Rpd = Av. Therefore 27K + 1K 1K = 25K 1K = 28Av. Q9 & Q10 make up a voltage amplification stage. Again, to operate properly, the same amount of current must flow through these transistors. Thus the voltage drop across R20 & R21 must be the same. Diodes CR16-CR19 (BYV26D) make up the Fixed Bias circuit for the output transistors. The body of the Diodes is mounted through the heatsink to properly track the temperature of the transistors. These Diodes were selected because they exhibit a 2mV decrease in Knee Voltage for every 1 degree (Celsius) increase in temperature. The Collectors of Q9 & Q10 are at 0 volts. Therefore the Bias Diodes provide 2 voltage drops (1.2 volts) to the Base of Driver Transistors Q13 & Q14. One Diode drop (0.6 volts) Biases on the Driver Transistors. The remaining 0.6 volts drops across the output transistors (Q15-Q18) in parallel, Biasing them on. Transistors Q11, Q12 and associated components comprise the Current Limiting or Short Proof protection circuit. There are usually two conditions which demand excessive output current from the amplifier. A shorted speaker cable, or a load impedance which is below the minimum rating of the amplifier. If these condition occur, the voltage drop across the Emitter Resistors (.33 5 Watt) will dramatically increase. On the positive side of the amplifier, C11 charges through R29 & R34. On the negative side C12 charges through R30 & R35. This will cause Q11 & Q12 to turn on. This limits the amount of signal which is available to the Base of the Driver Transistors (Q13 & Q14). CR20-CR23 make up a latching circuit that senses the signal through R22. This ensures that Q11 & Q12 turn on hard in conduction. When the fault condition is removed from the output, the current limiting will remain latched up until the input signal is removed. Q12 & Q14 are the Driver Transistors for the output section. Q15-Q18 are the output transistors. Notice on the schematic that the Base resistors carry the “Fp” designation. This indicates a Flame Proof/Fuse- KXR 200 POWER AMPLIFIER (CONT) Type resistor. They wont burn and they wont act like a fuse when exposed to an over-current condition. This prevents catastrophic damage to the output section. If an output transistor shorts Base to Collector or Base to Emitter, the resistor will simply open. In many cases the amplifier will continue to operate, but at a reduced power level. An increase in distortion may also become apparent. When replacing these resistors, ALWAYS use the Fuse-Type OEM part. PARTS LIST PREAMP PRINTED CIRCUIT BOARD ASSEMBLY QTY PART # DESCRIPTION REFERENCE DESIGNATION 1048497001PCB ASSY KXR 200 PREAMPSTUFFED 1048914000CABLE RIBBON 8 CKT 7 IN 1048836000CABLE RIBBON 12 CKT 23 IN 1037943000CAP AE RDL .33uF 50VC69 303869001CAP AE AX 1.0uF 100VC6,20,34 4026517001CAP AE AX 2.2uF 50VC14,28,42,60 3028459000CAP AE RDL 2.2uF 50V 20%C61,66,72 2038691001CAP AE AX 4.7uF 50VC64,70 4028463000CAP AE RDL 10uF 50V 20%C12,26,40,58 10025960001CAP AE AX 22uF 16VC1,2,15,16,29,30,43,44,45,46 5036954000CAP AE RDL 22uF 63V 20%C13,27,41,59,78 1028471000CAP AE RDL 47uF 50V 20%C63 5020909000CAP CD 47PF 1000V 10%C62,65,67,71,73 8025979000CAP CD 50PF 1000V 10%C5,11,19,25,.33,39,49,57 8038699001CAP CA 100PF 100VC3,4,17,18,31,32,47,48 1039262001CAP CA 680PF 50VC76 1039270001CAP CA 10000PF 50V 5% LLC51 4027256000CAP MPF .0015uF 100VC9,23,37,55 1027259000CAP MPF .0033uF 100VC68 1027261000CAP MPF .0047uF 100VC53 3027263000CAP MPF .0082uF 100VC7,21,35 1027265000CAP MPF .015uF 100VC74 1027267000CAP MPF .022uF 100VC75 4027275000CAP MPF .068uF 100VC10,24,38,56 9027278000CAP MPF .1uF 63V 10%C54, 79-86 4027281000CAP MPF .22uF 63VC8,22,36,52 1033477000CAP MPF .68uF 63V 10%C50 11031266000CONTROL RTRY 50K B TAPERR20,22,44,46,68,70,98,99,110,116,118 (FX SENDS, REVERB SEND, RETURNS, MASTER VOLUME) 40249287000CONTROL RTRY 50K 15A TAPERR17,41,65,95 (VOLUME CONTROLS) 13033002000CONTROL RTRY 50K CNTR DET BR7,10,13,31,34,37,55,58,61,82,85,88,91 (TONE CONTROLS) 15016795000IC DUAL OP AMP TL072U1-15 2030771000JACK PCB 2/CD SCCJ10,11 (FX SEND AND RETURN) 4016917JACK PCB 3/CD DCCJ2,4,6,9 (CHANNEL INSERTS) 5030987000JACK PCB 3/CD DOCJ1,3,5,8,12 (CHANNEL INPUTS, LINE OUT) 2048466000JACK RCA SINGLE PCB MOUNTJ14,15 1030762JACK XLR FM PC VERT MT (A/D)J7 (CHANNEL 4 IC INPUT) 1037249JACK XLR MALE PC VERT MTJ13 (LINE OUT) 73020888001JUMPER WIRE 22GAW1-73 1028841KNOB PUSH BUTTON MX/PXS1 1028097000LED 5X5MM YLLOW SLB-55YY3LD1 1028039LED RED 5X5 MM SLB-55VR3LD2 1048495PCB FAB KXR 200RAW PCB 3024937RES CF 1/4W 5% 10OHM LLR130,131,132 1024942001RES CF 1/4W 5% 22OHM LLR104 2024947001RES CF 1/4W 5% 47OHMR128,129 6024965001RES CF 1/4W 5% 1K LLR19,43,67,97,107,114 1024967001RES CF 1/4W 5% 1.2K LLR126 KXR 200 PREAMP PRINTED CIRCUIT BOARD ASSEMBLY (CONT) QTY PART # DESCRIPTION REFERENCE DESIGNATION 1024969001RES CF 1/4W 5% 1.5K LLR92 302497001RES CF 1/4W 5% 1.8K LLR14,38,62 2031819001RES MF 1/4W 5% 1.82K LLR73,74 1029005001RES CF 1/4W 5% 2K LLR105 8024971001RES CF 1/4W 5% 2.2K LLR8,16,32,40,56,64,94,124 3029455001RES CF 1/4W 5% 2.4K LLR83,86,89 3024972001RES CF 1/4W 5% 2.7K LLR11,35,59 1024973001RES CF 1/4W 5% 3.3K LLR120 1024978000RES CF 1/4W 5% 5.5K LLR108 4024981001RES CF 1/4W 5% 10K LLR109,115,133,134 3024983001RES CF 1/4W 5% 12K LLR119,121,122 8024986001RES CF 1/4W 5% 18K LLR6,15,30,39,54,63,81,93 16031818001RES MF 1/4W 1% 18.2K LLR1,2,4,5,25,26,28,29,49,50,52,53,76,77,79,80 15024987001RES CF 1/4W 5% 22K LL R21,23,24,45,47,48,69,71,72,100-102,111,117,125 3024993001RES CF 1/4W 5% 47K LLR103,106,112 6024996001RES CF 1/4W 5% 82K LLR9,12,33,36,57,60 9024997001RES CF 1/4W 5% 100K LLR18,42,66,84,87,90,96,113,123 1028861001RES CF 1/2W 5% 3.3K LLR127 2036375SPACER RND NYL .147X.250X.720LD1-2 1022904SWITCH PB PC MTS1 POWER AMPLIFIER PRINTED CIRCUI