Bandmaster 电路图 维修原理图.pdf

VOL 1M-A TREBLE 250K-A BASS 250K-A INTENSITY 250K-L 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 1N4007 + + 10F 100V 50K OT CT Choke 500p StandbyPower 2 Amp Slo-Blo + + 10F 100V A BC D B TREMOLO PEDAL + + 25F 25V + + 25F 25V 250p 250p + + 25F 25V LO T S G HIT S G LO T S G HIT S G VOL 1M-A TREBLE 250K-A BASS 250K-A VIBRATONORMAL BRIGHT SPEED 3M-RA 120p 120p BRIGHT .1F 630v 0.1F 100v .1F 630v .022F 630v .01F 630v .047F 630v .047F 630v .1F 630v .01F 630v .022F 630v .022F 630v + + 22F 500V + + 22F 500V + + 22F 500V Board dimensions 14.5 x 3.125 1N4007 1N40071N4007 1N4007 50F50F To all tube filaments OT Plates PWR GND D + + 25F 25V Board designed and installed by dbishopbliss, Oct, 2013 Redrawn and slightly modified by sluckey, Mar, 2019 1 1 470 470 1K4.7K 470 22K 15K 220K 220K 220K 220K 220K 100K 100K 100K 100K 100K 470K 1M 1M 1.5K 1.5K 1.5K 1.5K 1M 1M 470 22K 100820 T S G T S G SPEAKEREXT SPKR OT 15K15K 100K6.8K6.8K 10K - + LED .01F 630v T S G Vactrol VTL5C1 LN G 收音机爱好者资料库 Ra d i o Fa n s .CN C C 500pF .1 22K 470 1M 1M 100 100K.1 1500 220K .1 220K 82K 1500 820 1 1 470/3W 470/3W SPEAKERS (4 OHMS) 1 2 3 8 7 6 5 8 3 4 8 5 3 4 V4-A V4-B V5 6L6 V6 6L6 BA V4 12AT7 PHASE INVERTER POWER AMPLIFIER -44 -44 48Mv 48Mv 430 432 430 432 434436 424 424 235 97 61 65 97 220 Voltages measured with Fluke 87V on 03/11/2019. Line voltage set to 120VAC and Tremolo footswitch off. All controls set max CCW. 67 FENDER BAND-MASTER AMP AB763 .022 68K 68K 1M1500 100K 22 HI LO 100K 150022 1 2 3 6 7 8 V I B R A T O V2 12AX7 VIBRATO PREAMP DD TREBLE 250KA 250pF .1 .047 100K 6.8K VOLUME 1MA BASS 250KA 120pF BRIGHT 398398 259 265 0 22 0 TREBLE 250KA 250pF *.02 *.02 100K 68K 68K 1M1500 100K 22 HI LO 6.8K VOLUME 1MA BASS 250KA 100K 150022 1 2 3 6 7 8 N O R M A L V1 12AX7 NORMAL PREAMP DD .047 120pF BRIGHT * 5F6A Tone Stack capacitor values 398398 258258 22 00 220K 220K 50VAC NEUTRALLINE GROUND 3 AMP SLO BLO POWER 6.3 VAC to all filaments 222222 1K / 3W4.7K / 3W A 436V B 434V C 424 D 398V 50 330VAC 330VAC Connect here for tremolo on both channels BIAS 50K-L 22K + 10 15K 10 -49VDC 1N4007 BIAS RANGE 470 / 1W -60VDC Improved Bias Supply B SPEED 3M-RA 3 2 1 470K 1M 10K1M .01.022 .022 100K TREM FOOT SWITCH TREM-O-NATOR by sluckey/2deaf 434 Varies 148-345 0 Vactrol VTL5C1 INTENSITY 50K V3 12AX7 110VRMS5Hz 收音机爱好者资料库 Ra d i o Fa n s .CN Original project by dbishopbliss, Oct, 2013 Revised by sluckey, Mar, 2019 As found issues: Black wire on B+ diode terminal strip never soldered. Bad solder connection/broken lead on top 100F/450V reservoir cap. Second bias cap positive end never soldered. 47K resistor in bias circuit never soldered to ground turret. 220K grid bias resistor for V6 never soldered. CHNL 1 250pF treble cap never soldered. 50K INT pot should be 250K. Changes Removed reservoir cap/terminal strip assembly. Removed diode/terminal strip assembly. Added cap can for reservoir cap. Installed diodes on board. Replaced INT pot with correct pot. Replaced 47K bias resistor with 22K for proper 6L6 bias range. Replaced 4.7K/25F tremolo oscillator cathode components with red LED. Modified tremolo circuit to Trem-O-Nator circuit. (shown below) 收音机爱好者资料库 Ra d i o Fa n s .CN