BLUES JUNIOR SERVICE MANUAL - Tube Amp Information,

BLUES JUNIORSERVICE MANUALCONTENTS:NoticesSpecificationsTheory ofoperationParts lists:PCB assemblyChassis assemblyCabinet assemblyMiscellaneousSchematics/Service diagramFender Musical Instruments Corp., 8860 E. Chaparral Road Suite 100 Scottsdale, AZ 85250

BLUES JUNIORSERVICE MANUALNOVEMBER 1995IMPORTANT NOTICE:The information contained herein is CONFIDENTIAL and PROPRIETARY to Fender Musical Instruments Corp. Itis disclosed solely for use by qualified technicians for purposes of equipment maintenance and service. It is not tobe disclosed to others without the expressed permission of Fender Musical Instruments Co. All specificationssubject to change without notice.For warranty repair service, only Fender specified part numbers are to be used. It is recommended they also beused for post-warranty maintenance and repair.Parts marked with an asterick (*) indicate the required use of that specific part. This is necessary forRELIABILITY 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 asfollows:CAPACITOR CODESHARDWARE CODESCAP AECAP CACAP CDCAP MPFCAP MYCAP PFFBLXCRHWHMNIOHPPBPHPPHPSSMASMBSSTFZI Aluminum ElectrolyticCeramic AxialCeramic DiskMetalized Polyester FilmMylarPolyester Film/FoilRESISTOR CODESRES CCRES CFRES FPRES MFRES WW Carbon CompCarbon FilmFlame ProofMetal FilmWire Wound Black OxideChrome PlatedHex Washer HeadMachine ScrewNickel PlatedOval Head PhillipsParticle BoardPan Head PhillipsPan Head Phillips SemsSheet Metal "A" PointSheet Metal "B" PointStainless SteelThread FormingZinc Plated

BLUES JUNIORSPECIFICATIONSTypePR 295Input impedance:1M ohmPower output:15 Watts R.M.S. @ 5% T.H.DRated load impedance:8 OhmsSpeaker complimentOne 8 ohm 12" Eminence,replica of Jenson 41 cm)18inches(46 cm)9-13/16 inches(25 cm)31 lbs.(14 kg)THEORY OF OPERATIONJ1 is a high-sensitivity input with an input impedance of about 1MΩ. V1B is the first gain stagewhich also contains the "FAT" switch. The FAT feature is activated by grounding the nodebetween bypass capacitor C3 and R9. Via the FAT switch (S1) or the optional footswitch, thejunction of R52 and R54 can be grounded. With zero volts applied to the gate of Q1, the JFETwill essentially ground C3, activating the FAT feature.The output of V1B couples to the VOLUME control (R7). The VOLUME control is actually apreamp overdrive control that adjusts the level of distortion. C2 attenuates high frequenciesand C1 attenuates low frequencies at high distortion settings. This takes the edge off thedistortion and prevents the speaker from flapping. V1A provides a gain of about 40, and drivesthe tone control circuitry. After the tone controls, the signal is fed to V2B, which drives theMASTER volume control (R41). From the MASTER volume, the signal splits to feed the poweramplifier and the Reverb.U1A makes up a typical solid-state reverb drive circuit. U1B is the reverb recovery or sensecircuit, which drives the REVERB control (R51). The reverb signal is summed with the drysignal at C6, which couples to the input of the Phase Inverter (V3).The output tubes (6BQ5/EL84) are arranged in a push-pull configuration that will producefifteen (15 ) watts R.M.S. into eight (8) ohms @ 5% THD, 1kHz.The output bias is derived from the -15Vdc supply. The voltage divider at R31 & R37determines the bias voltage (-10.7 Vdc). C14 filters the ripple to 1mV or less.

BLUES JUNIORPARTS LISTQTYPART #PRINTED CIRCUIT BOARD ASSEMBLYDESCRIPTIONREFERENCE 01024964001024969001029005001PCB ASSY BLUES JUNIOR ALL VBUTTON PUSH SWITCH BLACKCABLE 6 CKT 3.2"CABLE JMPR 22GA 4 CKT 3.2"CABLE REVERB 30"CAP AE AX.47µF100VCAP AE AX22µF25V20%CAP AE AX22µF500VCAP AE AX47µF500V20%CAP AE RDL100µF25V20%CAP AE RDL220µF25V20%CAP AE RDL470µF50V20%CAP CA10PF100VLLCAP CD47PF1000V10%CAP CD100PF1000V10% C&FCAP CD250PF1000V10%CAP CD330PF1000V10%CAP CD1500PF1000V10%CAP CA2200PF100VLLCAP PFF.0022µF600VCAP PFF RDL .0033µF100V10%CAP PFF RDL.01µF100V10%CAP MPF RDL .01µF400V10%CAP PFF RDL .015µF100V10%CAP MPF RDL .022µF400V10%CAP MPF.033µF400VCAP MPF RDL.1µF250V10%CAP MPF RDL.1µF630V10%CONTROL 25K B SNAPINCONTROL 50KB SNAP INCONTROL SNAPIN 250K 10ACONTROL SNAPIN 250K BCONTROL 1M 10ADIODE 1N4003 LLDIODE 1N4006 800V LLDIODE 1N4448 SIGNAL LLDIODE HV 3KV 200MA LLDIODE ZEN 1N4744A 15V 1W 5%FSTN TAB MALE .250X.032 PCB MTFSTN TAB ML RTANG PCB .25X.032FUSE CLIP PCB .250 & 5MM FUSEFUSE QA 1-1/4X1/4 250V 2AFUSE QA 20mmX5mm 250V 1 AMPIC DUAL OP AMP TLO72JACK 1/4 PCB 2/CD SCCJACK 1/4 PCB 2/CD SCC INSLJACK PHONE PCB MONO CA PREMIUMJUMPER WIRE 22GA .5"LED RED PNL MT 7"PCB FAB BLUES JUNIORRES CF 1/4W5%47ΩLLRES CF 1/4W5%280ΩLLRES CF 1/4W5%1.5KLLRES CF 1/4W5%2KLL(STUFFED)(@ S1)CJ1,3CJ2,4,5(@ 8,9CP1-13,16-18CP14,15XF1F1(100V/120V ONLY)F1(230/240V EXPORT ONLY)U1J2(SPEAKER JACK)J3(FOOTSWITCH JACK)J1(INPUT JACK)W1-26LD1(RAW BOARD)R45R15R4,11,20,23,38R49

BLUES JUNIORQTYPART #PRINTED CIRCUIT BOARD ASSEMBLY (CONT)DESCRIPTIONREFERENCE 8028091029167014689RES CF 1/4W5%4.7KLLRES CF 1/4W5%7.5KLLRES CF 1/4W5%9.1KLLRES CF 1/4W5%10KLLRES CF 1/4W5%22KLLRES CF 1/4W5%33KLLRES CF 1/4W5%75KLLRES CF 1/4W5%100KLLRES CF 1/4W5%120KLLRES CF 1/4W5%130KLLRES CF 1/4W5%220KLLRES CF 1/4W5%330KLLRES CF 1/4W5%430KLLRES CF 1/4W5%470KLLRES CF 1/4W5%910KLLRES CF 1/4W5%1MLLRES MOX FP 1/2W 5%47ΩRES MOX FP 1/2W 5%100ΩRES CF 1/2W5%150ΩLLRES CF 1/2W5%91KLLRES CF 1/2W5%100KLLRES FILM 1W5%750ΩLLRES FILM 1W5%10KLLRES CF 2W5%2.2KSWITCH PUSH SLFLK SHORT STROKETUBE SOCKET 9 PIN PCB MOUNTXSTR N-CH JFET J111 34R17R3,10,19,39R57,58R33,55R32S1XV1-5Q1CHASSIS ASSEMBLYQTY1121111111116129411947297PART 0DESCRIPTIONREFERENCE DESIGNATIONCHS ASSY BLUES JUNIOR 120VBRACKET TUBE RETAINER PRO. JR.BUSHING SNAP 5/16X17/32 BLKBUSHING SR .500X.063X7/16 BLKBUSHING SR. .625X.062X37/64BLKBUSHING SR .625X.125X37/64 WHTCABLE ASSY PWR W/.250 TAB 120VCABLE ASSY PWR .250 TAB 100VCABLE ASSY PWR 220/240VCABLE ASSY PWR AUST .250 TABCABLE ASSY PWR 5A U.K.250 TABCHS BLUES JUNIORKNOB POINTED PUSH ON BLKLENS LED REDNUT HEX 3/8-32X3/32 TK NINUT HEX 4-40 EX LOCKNUT KEPS #8-32 ZINCPANEL FRONT BLUES JUNIORPANEL REAR BLUES JUNIORSCRW M 4-40X1/4 PHPS ZI W/WSHRSCRW TF 6-32X1/4 PHP ZISCRW TF 6-32X3/4 PHP ZISPRING, EXTENSION 1.81X.15"STANDOFF M/F 4-40 X 1/4LSTANDOFF NYLON PCB SNAPIN 1/2"(COMLETE CHASSIS)(@ V4,5)(@ OUTPUT TRANSFORMER)(@ REVERB CABLE)(@ POWER CABLE)(@ 230V & U.K. POWER CABLE)(POWER CABLE 120V ONLY)(POWER CABLE 100V ONLY)(POWER CABLE 230V ONLY)(PWR CABLE AUSTRALIA 240V)(P CABLE UNITED KINGDOM 240V)(RAW CHASSIS)(@ LD1)(@ SPEAKER & FOOTSWITCH JACK)(TUBE PCB MOUNT)(POWER TRANSFORMER MOUNT)(CHROME PANEL UNDER KNOBS)(@ BACK OF CABINET)(TUBE PCB TO CHASSIS MOUNT)(GND LUG & OUTPUT XFMR MOUNT)MAIN PCB TO CHASSIS MOUNT)(@ V4,5)(TUBE PCB TO CHASSIS MOUNT)(PCB MOUNT)

BLUES JUNIORQTYPART #CHASSIS ASSEMBLY (CONT)DESCRIPTIONREFERENCE 30010049969049967049968SWITCH TOGGLE DPST W/NUTSTUBE 7025/12AX7WA RUSSIAN MADETUBE 6BQ5/EL84WASHER FLAT .482X.709 NIWASHER LCK INTL 3/8X.681X.032XFMR OUTPUT 15WXFMR PWR BLUES JUNIOR 120VXFMR PWR BLUES JUNIOR EXPORTS1 (POWER SWITCH)V1,2,3V4,5(@ INPUT JACK & POWER SWITCH)(@ SPEAKER & FOOTSWITCH JACK)T1T2(120V ONLY)T2(100V,115V,230V,240V)CABINET ASSEMBLYQTYPART #DESCRIPTIONREFERENCE 22327CAB ASSY BLUES JR TWEEDBACK ASSY BLUES JR TWEEDCABLE ASSY SPKR RT ANG 13-1/2CLAMP CABLE NYL SCREW MNT 5/16CLOTH GRILLE VINTAGE TYPEEYELET RFLNGD .215 OD X.315 LGLIDE PRESS-IN .75 DIAGRILLE BAFFLE ASSY BLUES JRHANDLE 8 3/4" LEATHER BROWNHANDLE CAP NINAMEPLATE FENDER TWEED AMPSNUT 6-32 HEX EXT LOCKNUT T 10-32X3/4 STR 3 PRNG BLXNUT T 8-32X1/2 STR 3 PRNG BLXPIN ESCUTCHEON #18X3/8 NIREVERB UNIT 800 OHM 8EB2C1B DNSCREW M 10-32X1 PHP BLXSCREW M 10-32X1-1/2 THP NISCREW M 10-32X3/4 THP NISCREW M 6-32X1-1/2 OHP BRONZSCREW M 8-32X1 PHP STL NISCREW PB 8X3/4 PHP ZISPEAKER 12" 8 OHM 50 WATTSTOLEX TWEEDWASHER FLAT 8X7/16 NI(COMPLETE CABINET)(BACKBOARD)(SPEAKER CABLE)(REVERB PAN MOUNT)(COMPLETE GRILLE)(GRILLE MOUNT)(SPEAKER MOUNT)(HANDLE MOUNT)(NAMEPLATE MOUNT)(PAN)(SPEAKER MOUNT)(CHASSIS MOUNT)(BACKBOARD MOUNT)(GRILLE MOUNT)(HANDLE MOUNT)(REVERB PAN & CABLE CLAMP MNT)MISCELLANEOUSQTYPART #11049312049302DESCRIPTIONMANUAL OWNERS BLUES JUNIORSCHEM REDU W/SCV DIA BLS JRREFERENCE DESIGNATION

SUPPLEMENT TO:BLUES JUNIORp/n 021-3105-000 (120V)SERVICE MANUALReason for supplement: Reverb improvements and improved manufacturability require changes to the PCB and tothe BOM. This supplement contains parts lists and schematics of the new circuitry. Please file it with your originalservice manual.CONTENTS:Parts lists:PCB assemblySchematics/diagramsFender Musical Instruments Corp. 7975 North Hayden Road Scottsdale, AZ 85258

SUPPLEMENT TO: BLUES JUNIORPARTS LISTNOTE: SHADED ITEMS ARE FOR REFERENCE ONLYPRINTED CIRCUIT BOARD ASSEMBLYQTYPART #DESCRIPTIONREFERENCE DESIGNATION3200295330000050687000CABLE JMPR 22GA 4 CKT 3.2"CABLE JMPR 6 CKT .156 ROUNDPW2 PW4 PW5PW1 PW310028577000CABLE REVERB 30"@ 0051719000CAP AE AX .47uF 100V 20%CAP AE AX 22uF 25V 20%CAP AE AX 22uF 450V 20%CAP AE AX 47uF 16V 20%CAP AE AX 47uF 450V 20%C20C4 C18C26-28C1C25122002847400300284790030028489000CAP AE RDL 100uF 25V 20%CAP AE RDL 220uF 25V 20%CAP AE RDL 470uF 50V 20%C33C31 C34C30 C321100386980010039265001CAP CA 47pF 100VCAP CA 2200pF 170000017620000CAP CD 100pF 500V 5%CAP CD 470pF 500V 10%CAP CD 47pF 1000V 10%CAP CD 250pF 1000V 10%CAP CD 1500PF 1000V 00248530000024855000CAP MPF RDL .01uF 400V 10%CAP MPF RDL .022uF 400V 10%CAP MPF RDL .033uF 400V 10%CAP MPF RDL .1uF 250V 10%CAP MPF RDL .1uF 630V 10%C11 C29C6-7 030036234003CAP PFF .0022uF 400V 10%CAP PFF RDL .0033uF 100V 10%CAP PFF RDL .01uF 100V 10%CAP PFF RDL .015uF 100V 10%C2 9850000049401000CONTROL SNAPIN 25k BCONTROL SNAPIN 50k BCONTROL SNAPIN 250k 10ACONTROL SNAPIN 250k BCONTROL SNAPIN 1M 10AR14 MiddleR19 R45 Master, ReverbR13 BassR12 TrebleR5 10009165001DIODE 1N4003DIODE 1N4006 800V 1ADIODE 1N4448 SIGNALDIODE HV 3kV 200mADIODE ZEN 1N4744A 15V 1W 5%D5-6D1-4D9 FSTN TAB MALE .250x.032 PCB MTFSTN TAB ML RTANG PCB .25x.032FUSE CLIP PCB 1/4" & 5mm DUALP1-16P17-18F110031611000IC OP-AMP DUAL PC4560U1111003077100000276740000037036000JACK 1/4 PCB 2/CD SCCJACK 1/4 PCB 2/CD SCC INSLJACK PHONE PCB MONO PREMJ3 SpeakerJ2 FootswitchJ1 Input

SUPPLEMENT TO: BLUES JUNIORPRINTED CIRCUIT BOARD ASSEMBLY (CONT)QTYPART #DESCRIPTIONREFERENCE DESIGNATION10056975000LED RED PNL MT 010028955001002505900100258280010025069001RES CF 1/4W 5% 47ohm LLRES CF 1/4W 5% 820ohm LLRES CF 1/4W 5% 1.5k LLRES CF 1/4W 5% 2k LLRES CF 1/4W 5% 4.7k LLRES CF 1/4W 5% 7.5k LLRES CF 1/4W 5% 9.1k LLRES CF 1/4W 5% 10k LLRES CF 1/4W 5% 22k LLRES CF 1/4W 5% 33k LLRES CF 1/4W 5% 68k LLRES CF 1/4W 5% 75k LLRES CF 1/4W 5% 100k LLRES CF 1/4W 5% 130k LLRES CF 1/4W 5% 220k LLRES CF 1/4W 5% 430k LLRES CF 1/4W 5% 1M LLR39R24R4 R10 R17 R33-34R43R26 R40R25R29R2 R7 R15 R42R52 R57-58R21 R51R38R27R9 R11 R46R6R20 R31-32 R41 R44R18R1 R22-23 R37 28580001RES CF 1/2W 5% 150ohm LLRES CF 1/2W 5% 91k LLRES CF 1/2W 5% 100k LLRES MOX FP 1/2W 5% 47ohm LLRES MOX FP 1/2W 5% 100ohm LLR56R28R3 R8 R16 R30R54-55R35-362200310670010027349001RES FILM 1W 5% 750ohm LLRES FILM 1W 5% 10k LLR50 R53R48-4910041258001RES MOX 2W 5% 2.2k LLR471100280910000028104000SWITCH PUSH SLFLKBUTTON PUSH SWITCH BLACKS1AT S150029167000TUBE SOCKET 9 PIN PCB ANDOFF M/F 4-40 x 1/4LNUT HEX 4-40 EX LOCKSTANDOFF NYL PCB SNAP 1/2" BLK10014689003XSTR N-CH JFET J111 TO-921REF00572760000057275000PCB FAB BLUES JUNIORSERVICE DIAGRAMQ1

1 048827 fuse qa 1-1/4x1/4 250v 2a f1 (100v/120v only) 1 020789 fuse qa 20mmx5mm 250v 1 amp f1 (230/240v export only) 1 016795 ic dual op amp tlo72 u1 1 030771 jack 1/4 pcb 2/cd scc j2 (speaker jack) 1 027674 jack 1/4 pcb 2/cd scc insl j3 (footswitch jack) 1 037036 jack phone pcb mono ca premium j1 (input jack) 26 020888001 jumper wire 22ga .5 .