Fender KXR-60-SM Service Manual

CONTENTS:

Notices

Specifications

Circuit Description

Parts lists:

PCB assembly

Chassis assembly

Cabinet assembly

Miscellaneous

Schematics/diagrams

KXR 60

KEYBOARD EXTENDED RANGE

SERVICE MANUAL

Fender Musical Instruments Corp. 7975 North Hayden Road Scottsdale, AZ 85258

KXR 60

KEYBOARD EXTENDED RANGE

(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 (
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 Electrolytic BLX = Black Oxide
CAP CA = Ceramic Axial CR = Chrome Plated
CAP CD = Ceramic Disk HWH = Hex Washer Head
CAP MPF = Metalized Polyester Film M = Machine Screw
CAP MY = Mylar NI = Nickel Plated
CAP PFF = Polyester Film/Foil OHP = Oval Head Phillips

RESISTOR CODES

RES CC = Carbon Comp SMA = Sheet Metal "A" Point
RES CF = Carbon Film SMB = Sheet Metal "B" Point
RES FP = Flame Proof SS = Stainless Steel
RES MF = Metal Film TF = Thread Forming
RES WW = Wire Wound ZI = Zinc Plated

*

) indicate the required use of that specific part. This is necessary for RELIABILITY

PB = Particle Board
PHP = Pan Head Phillips
PHPS = Pan Head Phillips Sems

KXR 60

SPECIFICATIONS

Product Release No.: PR 299 (This is not a model number)

POWER AMPLIFIER SECTION:

Power output: 50 Watts RMS
Distortion at 50 Watts: Less than .1% @ 1kHz, before compression

Less than 1% @ 1kHz, maximum compression

Rated load impedance: 8 Ω

Sensitivity: 370 mV RMS

Input impedance: 33K Ω

DELTACOMP Range: 20dB

PREAMP SECTION:

Input Impedance: 36k Ω

Sensitivity for 50 watts: 28 mV
CHANNEL and MASTER VOLUME
at maximum all tone controls at “0”

Equalizer: Low +/- 12dB at 100Hz (shelving)

Low Mid +/- 12dB at 338Hz
High Mid +/- 12dB at 1188Hz
High +/- 12dB at 4 kHz (shelving)

DIMENSIONS: Height:22" (55.9 cm)

Width: 18" (45.7 cm)
Depth: 12" (30.5 cm)

Weight: 46 lbs. (21 kg)

Product specifications are subject to change without notice

KXR 60

CIRCUIT DESCRIPTION

Preamp

The Channel One input will accept a Balanced or Unbalanced signal via a ¼” Phone plug. U1B provides a
gain of 1, and rolls off high frequencies at about 128kHz. The signal then couples to the second half of the
input stage.

Located within the negative feedback loop of U1A is the Channel One Volume control. It provides a
minimum gain of 1, and a maximum gain of 15. At maximum gain, Capacitor C6 rolls off the high
frequencies at about 47kHz.

The input stage also features a function that shorts across the Volume control via a switch contact in the
¼” input jack. This causes U1A to remain locked into a Unity gain mode, disabling the Volume control, until
a plug is inserted into the jack. This reduces noise in the input circuitry. Channel Two is identical to
Channel One.

The two channels sum together to feed the Reverb Drive stage U3A, and the Summing Amp U4B. U3B
senses the return signal from the Reverb Pan . R24 and C19 provide a slight boost in the high frequencies
. R23 and C18 roll off low frequencies. This produces a fairly bright reverb sound. To eliminate noise,
C17 limits the high frequency response to about 5kHz. All ground connections in the Reverb circuitry are
routed through a dedicated Reverb Ground trace to the Star Ground point on the circuit board. This
eliminates any bleed through of noise into other audio ground paths.

U4B sums the dry signal with the Reverb return signal and then drives the Equalizer circuit. Gyrators U5B,
U6B, and U6A are used for the Low (100Hz), Low Mid (338Hz), and High Mid (1588Hz) bands. The High
band uses a single pole shelving filter (R40,C31) at 4kHz. U5A performs the Boost/Cut function, and also
drives the Effects Loop.

The Tape in jacks are buffered by U7A and sum with the main signal just prior to the Effects Loop. The
Effects Loop Send is capable of providing a pseudo balanced signal if desired. This helps to reduce noise
and hum. The Effects Loop Return will accept an Unbalanced or Balanced input.

U7B buffers the signal from the Effects Loop, and drives the Master Volume control. R55 and C39 boost
the low frequencies at 220Hz. Between the output of U7B and the Master Volume control, C40 and R56
boost high frequencies. The boost in Low and High frequencies provide a slight “Smile Curve” response.

DELTACOMP™

U8B is a unity gain amplifier that drives the power amp stage. U9 (CA3080A) is an Operational
Transconductance Amplifier (OTA). In conjunction with U8B, it acts as the gain reduction circuit for the
Deltacomp™. The attack/release circuit for the DeltaComp™ contains the Diode, Resistor, and Capacitor
network that drives the base of Q8 (MPSA63). Comparator U4A senses the output of the power amplifier.
As the amplifier approaches clipping, the output of U4A toggles negative. The negative voltage through
Diodes CR14-17 charges Capacitors C54-C57 all at once in parallel as a one-pole filter through a single
time constant made up with R84. R84X (C54+C55+C56+C57) = 2.2K x 8.8uF = 19.4mSec.

KXR 60

DELTACOMP™ (CONT)

As the capacitors charge, the negative voltage at the base of transistor Q8 turns on this Darlington device.
Current flows from the Collector of Q8 to pin 5 of U9. This current controls the output amplitude of U9.
The inverted output from U9 mixes with the signal at the input of U8B (pin 5) causing 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 Comparator toggles positive, removing the negative control voltage from
the attack/release circuit. The blocking action of Diodes CR14-CR17 force Capacitors C54-C57 to
discharge(Release) through a 4-pole filter with different time constants, through Resistor R85.

Turn-on delay

JFET Q7 and associated components provide a 2 - 3 second turn-on delay for the audio input to the power
amplifier. Upon power-up, the negative16 volts charges Capacitor C45 through Resistor R64. The
negative gate voltage pinches off the JFET, removing the ground from the input of the amplifier. When
switching the power off, C45 immediately discharges through Diode CR1, grounding the input of the
amplifier.

TROUBLE SHOOTING TIP: Check for proper operation of this circuit when experiencing excessive turn­on 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 fo the +/- power
supplies. Usually a mismatch in the Filter Capacitors will cause this problem. It’s easy to look at both
supplies on an oscilloscope. Invert one scope input and check for even discharge to zero volts.

Power Amplifier

U10 is a high voltage op-amp (MC1436) that provides voltage gain for the power amplifier. Bootstrap
Capacitors C47 and C48 sense the output through R104. This provides more voltage swing for the opamp
with respect to the amplifier output.

Diodes CR2 - CR5 (BYV26D) make up the Fixed Bias circuit for the output transistors. The bodies of the
Diodes mount 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. Pin 6 of U10 is at 0 Vdc. Therefore the Bias Diodes provide 2 voltage drops (1.2 volts) to the
base of Darlington output Transisitors Q5 and Q6.

Diodes CR6 - CR9 make up a voltage clamp protection circuit. If the bases of the output transistors reach

4.5 volts with respect to the output, the diodes will turn on, clamping the voltage.

The output signal feeds through the Headphone Jack before driving the 15” speaker and dual piezo horn.
Inserting a ¼” plug into the Headphone Jack will mute the speaker and horn.

PARTS LIST

PRINTED CIRCUIT BOARD ASSEMBLY

QTY PART # DESCRIPTION REFERENCE DESIGNATION

4 038690001 CAP AE AX 1.0uF 100V C18,25,43,46
5 026517001 CAP AE AX 2.2uF 100V C45,54,55,56,57
1 038692001 CAP AE AX 10uF 35V C51

19 009512001 CAP AE AX 22uF 25V 20% C1,2,5,7,8,11,13-15,20,23,24,33-36,49,50,64

4 049521000 CAP AE AX 47uF 50V C47,48,62,63

KXR 60

PRINTED CIRCUIT BOARD ASSEMBLY (CONT)

QTY PART # DESCRIPTION REFERENCE DESIGNATION

2 031756 CAP AE 4700uF 50V C60,61

11 039256001 CAP CA 68PF 100V LL C3,4,6,9,10,12,21,22,32,37,38

2 039262001 CAP CA 680PF 50V C17,30
1 039266001 CAP CA 3300PF 100V LL C16
1 038702001 CAP CA 6800PF 100V LL C28
1 03927001 CAP CA 10000PF 50V 5% LL C31
3 038703001 CAP CA 1uF 50V LL C27,52,53
1 033578003 CAP PFF RDL .001uF 100V 10% C44
1 033581003 CAP PFF RDL .0033uF 100V 10% C41
1 036234003 CAP PFF RDL .015uF 100V 10% C26
3 033591003 CAP PFF RDL .033uF 100V 10% C39,40,42
1 033592003 CAP PFF RDL .047uF 100V 10% C19
1 033594003 CAP PFF RDL .056uF 100V 10% C29
1 024854000 CAP MPF RDL .1uF 400V 10% C59
1 041501 CAP MPF AX 2.2uF 100V 10% C58
1 038656000 CONTROL 10KB R25 (REVERB)
4 038655000 CONTROL 50KB W/CD R30-33 (EQUALIZER)
1 038716000 CONTROL 2K B SNAP IN R58 (MASTER)
2 037323000 CONTROL SNAPIN 50K 15A R7,15 (VOLUME)
9 00626001 DIODE 1N4448 75PRV SIGNAL LL CR1,6,9,12-17
2 064089001 DIODE 1N4003 CR10,11
4 029045000 DIODE 6A 400V 6A4 LEAD FORMED CR18-21
4 028776000 DIODE BIAS BYV26D LEAD FORMED CR2-5
2 027329001 DIODE ZEN 1N5228B 3.9V 5% LL CR7,8
2 028119000 DIODE ZEN 1N5353B 16V 5W 5% CR22,23

13 025802000 FSTN TAB MALE .250X.032 PCB MT CP1-4,6-9,11-15

2 026000001 FSTN TAB MALE PCB MT .187X.032 CP5,10
2 025996000 FUSE CLIP PCB .250 & 5MM FUSE XF1
1 048827000 FUSE QA 1-1/4X1/4 250V 2A F1 (100/120V ONLY)
1 020789 FUSE QA 20mmX5mm 250V 1AMP V1 (EXPORT 220/230/240V ONLY)
1 027404000 IC CA3080AE OTA U9
8 016795000 IC DUAL OP AMP TL072 U1-8
1 028047000 IC OP AMP MC1436/SG1436Y U10
2 040903 INSULATOR MICA TO-218 @Q5,6
5 031570000 JACK PHONE PCB STEREO PREMIUM J1,2,4,5,6
1 025933000 JACK PHONO DUAL PC MTG J3 (TAPE IN)
2 048466 JACK RCA SINGLE PCB MOUNT J7,8 (REVERB PAN CONNECT)

22 020888001 JUMPER WIRE 22GA

1 028039000 LED RED 5X5MM SBL-55VR3 LD1
1 049248003 PCB ASSY KXR 60 STUFFED
5 024937001
2 024952001
1 0296060001
8 024965001 RES CF 1/4W 5% 1K LL R23,42,46,62,65,72,73,78
4 024971001 RES CF 1/4W 5% 2.2 K LL R19,56,57,84
3 024972001 RES CF 1/4W 5% 2.7K LL R35,37,39
1 029610001 RES CF 1/4W 5% 3K LL R40
4 024973001 RES CF 1/4W 5% 3.3K LL R6,8,14,16
2 024977001 RES CF 1/4W 5% 4.7K LL R89,90
1 024979001 RES CF 1/4W 5% 6.8K LL R92
2 025942001 RES CF 1/4W 5% 7.5K LL R71,74

11 024981001 RES CF 1/4W 5% 10K LL R43,44,45,60,79,81,82,85-88

2 024986001 RES CF 1/4W 5% 18K LL R29,41

12 031818001 RES MF 1/4W 1% 18.2K LL R1,2,3,5,9,10,11,13,51-54

2 024987001 RES CF 1/4W 5% 22K LL R27,55
3 024989001 RES CF 1/4W 5% 33K LL R59,80,83
5 024993001 RES CF 1/4W 5% 47K LL R21,22,28,66
1 024994001 RES CF 1/4W 5% 56K LL R77
7 024997001 RES CF 1/4W 5% 100K LL R4,12,26,34,36,38,47
1 024998001 RES CF 1/4W 5% 120K LL R91
2 025069001 RES CF 1/4W 5% 1M LL R63,64

RES CF 1/4W 5% 110 Ω LL
RES CF 1/4W 5% 100Ω LL
RES CF 1/4W 5% 510 Ω LL

R17,18,20,49,50
R24,61
R48

KXR 60

PRINTED CIRCUIT BOARD ASSEMBLY (CONT)

QTY PART # DESCRIPTION REFERENCE DESIGNATION

1 028861001 RES CF 1/2W 5% 3.3K LL R103
3 028045001
2 028030001
4 029722001 RES FILM 1W 5% 1K LL R95-98
2 028029001 RES FILM 1W 5% 1.5K LL R68,69
2 028028000
1 048467
2 029047000
1 048468
2 027638000 SCREW TF 4-40X3/8 HWHS ZI .1” HD @Q5,6
2 038900000 SCREW TF 6-32X1/4 PHP ZI PCB TO HEATSINK MOUNT
2 028169000 WSHR SHLDR NYL 5/32/1/4 @Q5,6
1 014689003 XSTR N-CH JFET J111 TO-92 Q7
1 028114000 XSTR NPN TIP 142 TO-218AC Q5
1 014408003 XSTR PNP DARLNGTON MPA 63 TO 92 Q8
1 028115000 XSTR PNP TIP 147 TO-218AC Q6

RES FILM 1W 5% 220 Ω LL
RES FILM 1W 5% 680Ω LL

RES WW BT 5W 10% .47Ω
RES WW BT 5W 10% 39Ω
RES WW BT 7W 10% 270Ω
RES WW BT 10W 10% 47Ω

CHASSIS ASSEMBLY

QTY PART # DESCRIPTION REFERENCE DESIGNATION

1 007565 BUSHING SR .625X.125X37/64 BLK @ POWER CABLE 100/120V ONLY
1 010401 BUSHING SR .625X.125X37/64 WHT @PWR CABLE 230/240V ONLY
1 026527 CABLE ASSY PWR 120V .187 TABS 100/120V ONLY
1 026528 CABLE ASSY PWR 230V .187 TABS 230V ONLY
1 036479 CABLE ASSY PWR AUST .187 TABS 240V AUSTRALIA ONLY
1 040992 CABLE ASSY PWR 5A UK .187 TABS 240V UNITED KINGDOM ONLY
1 028560 END BELL XFMR 85W TRANSFORMER MOUNT
1 049977 HEATSINK BAR KXR 60 COUPLER TO CHASSIS
8 048357
4 028591 NUT ACORN 8-32 TRANSFORMER MOUNT
5 031647 NUT HEX 12MMX1MM NI @PHONE JACKS
1 0492520 PANEL FRONT KXR 60
1 049253 PANEL REAR KXR 60
1 041595 SCREW 6-32X3/16 PHP STL ZI SEMS
6 017433 SCREW M 6-32X3/8 PHP BLX PCB MOUNT
1 031868 SCREW PLASTITE 4X1/4 PHP BLX @RCA JACKS
3 037988 SCREW TF 8-32X1: HWH BLX
1 025935 SWITCH DPST .187 TAB (DOM) POWER SWITCH
4 030007 WSHR LCK INTL 8X.330X.02 ZI TRANSFORMER MOUNT
1 027668 XFMR PWR 120V 85W 120V ONLY
1 039357 XFMR PWR EXP DELUXE 112 100V/115V/230V

KNOB CUSTOM BLK/OFF WHT 180°

R93,94,104
R67,70

R76,76
R100
R101,102
R99

CABINET ASSEMBLY

QTY PART # DESCRIPTION REFERENCE DESIGNATION

1 049251 CAB ASSY KXR 60 COMPLETE CABINET
1 025722 CABLE REVERB 1100MM REVERB CABLE
1 022491 CLAMP CABLE NYL SCRW MNT 5/16

.377 026317 CLOTH GRILLE BLACK PVC

6 031867 CORNER 2 HOLE W/ NOTCH BLK PWDRD
2 031840 CORNER 3 HOLE BLK PWDRD
4 029821 EYELET RFLNGD .15OD X.315 L REVERB PAN MOUNT
4 027849 GLIDE CAB 1.24X335 BLX WAX STEEL ONLY , NO INSERT
1 049251010 GRILLE ASSY KXR 60 COMPLETE GRILLE
1 027846 HANDLE 9.25” NO LOGO RUBBER ONLY, NO INSERT
2 031845 HANDLE CAP 2 HOLE BLK PWDRD
1 049260 HORN CERAMIC PIEZO KXR 60
4 019275 INSERT GLIDE CUSHION 1.27 DIA RUBBER ONLY
1 032524 INSERT HANDLE SPRING STEEL

1 029906 NAMEPLATE FENDER GENERIC SMALL LOGO

4 021972 NUT T 10-32X3/4 STR 3 PRNG BLX SPEAKER MOUNT

KXR 60

CABINET ASSEMBLY (CONT)

QTY PART # DESCRIPTION REFERENCE DESIGNATION

1 028055
4 017441 SCREW M 10-32X1-1/2 OHP STL BLX SPEAKER MOUNT
4 036199 SCREW M 8-32X1-1/16 OHP BLX CP CHASSIS MOUNT
5 029828 SCREW PB 8X3/4 PHP ZI REVERB PAN MOUNT
4 9904101110 SCREW PB 8X5/8 THP BLACK
2 018113 SCREW SMA 4X1/2 OHP BLX LOGO MOUNT

14 026576 SCREW SMA 8X5/8 THP BLACK CORNER MOUNT

4 017942 SCREW WOOD 8X1 FHP BLX GLIDE MOUNT
4 026577 SCRW M 10-32X1 PHP BLX
1 047539

REF 026570 TOLEX BLACK LT WEIGHT

4 029527 WSHR FNSH 8-5/8 FLNGD BLX WX CHASSIS MOUNT

REVERB UNIT 800 Ω 8EB2C1B DN

SPEAKER 12” 8 Ω 75W BXR 60

MISCELLANEOUS

QTY PART # DESCRIPTION REFERENCE DESIGNATION

1 049254 MANUAL OWNERS KXR 60
1 049245 SCHEM REDUCED KXR 60

REVERB PAN