Roland TR-77 Service Notes
Contents
1. Q Pig 23 1 decay lime Connect amp trigger pulse with terminal SD on PCB Measure voltage of output at terminal O on PCB Check the frequency within regular cycles And then turn semifixed resistor VR312 so that the level of Noise may reach 2 0V And amp lso check decay time within regular time Adjustment of Tambourine Connect a trigger pulse with terminal TB turn semifixed sistor VR311 so as to get the output voltage as O 4V And check decay time within standard time 22 f Adjustment of Guiro The square wave is only used for Guiro Connect trigger No 6 on the Logic PCB in oase of Guiro and connect trigger No 12 with terminal Gu on the voice generator board To begin with check the wave form on the collector of 6410 by the oscilloscope and adjust semifixed resistor VR309 so as to make the period of negative pulse as 13 5 Check the period of the pulse to be no more than 8 mS in adding positive square wave to the terminal No 5 on the voice generator board The output of No 12 on the Logic PCB is conveniently used for EXT trigger of the oscilloscope Fig 24 FA f LL EE Ew 8 mS Adjust the semifixed resistor VR310 so that the voltage of White Noise may reach O 5V Figs 25 In case that Noise section is zero The period of ringing is 3500 5000Hz Fig 26 ie 23 C Adjustment of the Drum section BD LC LB HB RS2. gt cc o lt e es e lt 2 9 2 I gt I cc 2 lt c THE 7th EDITION Printed in Japan 76 Nov GENERAL BLOCK DIAGRAM SMOTION 1 SECTION 2 SECTION 3 SECTION 4 SECTION 5 SECTION 6 SECTION 7 SECTION 8 SECTION 9 SECTION 10 CONTENTS SPECIFICATIONS THEORY OF OPERATION GENERAL NOTICE DISASSEMBLING 2 LOGIC CIRCUIT RHYTHM SWITCH ASSEMBLY 12 VOICE GENERATOR CIRCUIT 16 CONTROL CIRCUIT 2 18 ALIGNMENT PROCEDURE 20 PARTS LIST 28 on nA WwW 2 VOICE GEM BOARD vG 2 CIRCUIT DIA 403 006 VR608 ee VOLUME 12 LOGIC BOARD 61 3 CIRCUIT DIA 402 011 247771777 Memes SD VOLUME x 3 34 37 3B 4 2 MEE GU VOLUME PULSE LBC d M 8D VOLUME 100 3 9 4 5 20 2 VR601 39 20 42 y m m LATIN B i RHYTHM A s ue lt RS 4 4 1 MIO I J PILOT LAMP a
3. OEE TTT aa s Tes enr Aue lel llli 167 c58 8 MTE 53 il v2 24 S S _______ IN C EE _ l _ hie x TEREN pa ez E kis a HX lI 8 25 SIEHT Ri26 E 2 54 H 2 55 A e amp 2 50 bred 47 RID2 s RAG 47 3 UNLESS OTHERWISE SPECIFIED ALL RESISTOR ARE IN OHMS 270K RHYTHM 77 ALL CAPACITOR ARE IN 50 039 ALL DIODE ARE TYPE 151555 MATRIX CIRCUIT 73 Fig 6 Losic Output Timing Chart Be 26 28 30 32 48 20 22 24 gt 6 4 12 bd Y ini _ u Vw N i 1 MEME i 1 i MEME i MEE v 3x m ejus mS lt n 4 2 i gt mV T ind i i 3 E M 3 i 3 T gt Xi Y gt ri EE IN _ 3 lt 4 1423 loo ile TT 271 gt qo Ni r eij t the gt rep tert t zm 2 lt 9 3 gt s X 3 221 gt 3 3 3 gt gt
4. Up Tempo Switch works remarkably when you want to double the tempo suddenly and enjoy performance Press the switch ON and the tempo will be doubled instantly With OFF switch pressed the tempo is restored to the former state Up Tempo Switch adds interest and pleasure to your performance 2 2 2 3 Rhythm Selector Tae selection of rhythm patterns is made up by push button switch di vided into two stages on the control panel and a rotary switch Push buttons at the two stage are separated beat buttons for the vari ation section and a JAZZ section and LATIN section The gate circuit provides for working on the push of LATINS to select the signal from pulse pattern generator lest two trains of buttons should inter fere with each other When this button is turned off the output signal of the diode matrix is biassed by positive voltage and the voice generator will not work Therefore when the push button LATIN is not pushed even if the button of LATIN section is pushed the rhythms of LATIN will not come out On adjusting the push button to LATIN you are listning to rhythm of LATIN While you push JAZZ section button the push button LATIN is automatically returned you will hear JAZZ section rhythm as soon as the LATIN rhythm gose out And yet rotary switch for variation works by pushing 2 BEAT or 4 BEAT button The neces sary pattern of the rhythm indicated by buttons i
5. gt gt gt I gt X gt gt io TE 3 L 2 P Vw T2 w meri sica m Va v X eda REL Y sn o 5 MR a w r 11 SECTION 6 RHYTHM SWITCH ASSEMBLY 6 1 Jazz Section Switch Assembly RS 3 Fig 7 m XXX X DX Xt Xt K MU 25 LE B 2154 So D NP e 6 2 Latin Section Switch Assembly RS 4 Fig 8 __ l L l Tm MEX XX 052 011 Pes 6 3 Rhythm Pattern Fig 10 B Latin 9 Fig Jasse 22 ou 99 m 9 L TIT adi sm IO LIII died 707771727 141711 urbe e H l 20 3 z w i 20 22 04 28 29 30 6 8 4 8 20 22 24 26 28 30 32 ib 02 6 8 BOSSANOVA 0 9 99 D c9 eod 2 24 0 2 wb ae ad 26 B 6 4 Variation Section A Relation Diegram of Beat Selector and Fig 11 Rotary Switch ROTARY SWITCH BASS BASS SNARE FOX TROT 1 FOX TROT 2 SWING 1 SWING 2 MARCH SWING 3 PARADE SHAFFLE ED 2 BEAT 4 BEAT 14 B Rhyth
6. CB C 2 Adjustment of Bass Drum Connect a trigger pulse with terminal BD on PCB and check the level of output voltage frequency and decay time within regular value To represent frequency time of a period at wave form of vibration decay time is measured and its reciprocal number is shown a unit of Hz 65Hz is nearly 15 4mS When the frequency of BD is over or under the regular value Adjust the capacitors C344 or 345 In case that amp capacitor or value is changed check frequency voltage and decay time again Fig 27 dp Output voltage of the Drum section is shown by max of plus side e voltage T decay time b Adjustment of Low Conga Connect a trigger pulse with terminal LC on PCB adjust semifix ed resistor VR307 so that the level of output voltage may reach 4 0V Check frequency and decay time within regular time When frequency of LC is over or under the reqular value adjust capacitors C337 or 338 In case that a capacitor or value is chang ed check frequency voltage and decay time again c Adjustment of Low Bongo Connect amp trigger pulse with terminal LB on PCB adjust semifix ed resistor VR306 so that the level of output voltage may reach 1 5V Cheek frequency and decay time within regular time 24 g When frequency of LB is over or under the regular value adjust cap amp citor 331 In case that capacitor or value is changed check frequ
7. check frequency voltage and decay time again Adjustment of Rim Shot Connect amp trigger pulse with terminal RS on PCB hon tie l re uency of 85 is im reference to CB 2r uncer rerular volue edgust Fir 28 c n C310 3 1 thet s crorei itomr or value is H PEE 1 0 w enoneed check fro uency tine 25 9 4 Adjustment of Control board A The start switch circuit of touching type Check of the oscillated frequency Connected the Oscilloscope to the collector of transistor Q901 check the oscillated frequency to be not less than 1700KHz 0 59 Sec If the frequency is no more than 1700KHz turn the core of coil 1901 094 465 counter clockwise to make the frequency within regu lar value b Check of the oscillated voltage Connected the Oscilloscope of which the frequency band is not less than 2 000KHz to the collector of transistor 9901 And check the oscillated voltage to be not less than 5 5V p p c Check of the oscillation stoped Connect the Oscilloscope to the collector of transistor Q901 touch the Badge Touch Plate with hand softly and then check the wave form of oscillated frequency disappear not less V ECL the B Sound source of metronome Fig 29 than S5V ge no more x 0 52 Sac Connect oscilloscope with the power terminal O on Voice Generator as in chapter
8. e 2 gt 5 6K IK EET x RT ge C933 47K d t as 100P n 957 00 Cor K Del 05 RW 5 2 15 0 K 10K G 3 ND 421 Re 52 1204H x ceo Mm 056 es PI R756 RII 2 47K 56K 0047 R9 995 056 N B i IK Ne 939 FS R93 040 47 M E 930 w R953 Rds ee 2 7K MS amp 952 7 Suo ous 947 7272 Na RHYTHM 77 15K 01 2 Res CONTROL BOARD CIRCUIT 56K C727 KOf R9 7 744 R454 955 220 5 6 K SEK SECTION 9 ALIGNMENT PROCEDURE 9 1 Logic Circuit A Adjustment of Tempo Speed B Rating For oscillation period of Master Oscillator Q1 92 37 5mS QUICK 300mS SLOW 10 Adjustment In case of measuring wave form of logic output terminal or by the oscilloscope a At the right end of tempo slide volume QUICK adjust semifixed resistor so as to make the period of measured negative pulse 37 5 5 b At the left end of tempo slide volume SLOW adjust semifixed re sistor VR2 to make the period of negative pulse 300m5 c Repeat above mentioned procedures and adjust semifixed resistor VR1 and VR satisfactorily 37395 300 S Logic output terminal T a b Fig 17 Connecting for oscilloscope D Checking the wave form of c
9. No 3 and press the button of metronome The trigger pulse shows No 5 Adjust the semifixed resistor VR903 so that the frequency may come to1480Hz 0 68mS And check the output voltage and decay time within standard time Adjustment of Reset time Connect the oscilloscope with reset terminal R on Logic board or on Control board The terminal R on the Control board is the col lector Q906 of oneshot multivibrator Touch the badge with hands or connect footswitch FS 1l with start jack ON OFF and adjust the semifixed resistor 901 so that the pulse width may come to 30mS 3 5 V Reset lime 0 30mS 20 30 5 io touch badge Logic board Master Oscillator Master Oscillator will run Master will run r Fig 30 will stop 26 D Check of 5 and Stop using Footswitch Connect the Footswitch FS 1 or the substitute with the start switch jack in the rear chassis and check if they work the same way as Item 4 3 E Adjustment of Pade Time Connect oscilloscope with the terminal O on Voice Generator set the rhythm on Bass Drum of 2 Beat and make the rhythm start Adjust the semifixed resistor VR603 soldered on the terminal strip so that the volume of Bass Drum will fall down to 90 in case the fade time volume is slide on the right end SHORT from the left end LONG 100 90 And set the rhythm on Rhumba or Mambo of Latin push the fade out button and adjust the semifixe
10. 304 Sok LS 39K 3 ud R316 22K 315 EE 1 305 vR305 D306 T 210 C332 093 S R319 022 pd 306 F yR306 056 DH 50 C339 01 340 056 Gi Ou 05 25 372 Qi Selected for Noise R 36 220K R23 EP 328 R329 SSK 0309 03 001 K C364 07 056 R330 5 R340 ZZK R341 K casg 470 91 C365 01 30 look B 358 131 U WOK 18 40 mH c373 9 C355 L C356 470 1304 45 mH 94 C35B C354 0022 4 NOS 305S 605 8 305 DIESA 2I MA CIE bey IEY 0001262 21 0 SECTION 8 CONTROL CIRCUIT 8 1 Control Board Assembly 0 1 Parts Layout Fig 15 ARE 22 cu ege ern a TER TA 15 rs 3 Dar 189 Ni ff p ae ie Eae J 904 A090 Se n gt TS 0401 0407 690 Ogi 25 828 or Q 2901 D912 151555 or 152473 75 78598 I 5 Circuit Diagrem OF 1 Fie 16 ze La a 4 aoa UNLESS OTHERWISE SPECIFIED 6 ALL RESISTOR ARE IN OHMS 4W 151850 74 ALL CAPACITOR ARE IN MFD zo aw 68 ww 84 ALL TRANSISTOR ARE TYPE 2SCB28 R 9 ALL DIODE ARE 151555 OR 152473 cus dZ cue a 3
11. d resistor VR902 so that the decay time will be 5 8 seconds at SHORT position Next check if the decay time at LONG position is about double of it at SHORT position Standard outputs of percussion instruments mS ea LAE 2 3 3 0 3 6 60 25 10 90 120 160 15 18 523 o Lt 5 I IP O OIO ON gt E oie j I no Oe ss T 0 85 B 0 48 0 426 0 38 EB 2100 2350 2600 n3 x NO O n ND tw Co e UJ s M2 io inm OQ O jn jm 40 100 2 300 400 220 290 P 13m ED e ble Re 3 3 O mi r O O Co C V n 4 C N no Qiu UJ NEN 22 is Metronome Standard trigger pulse No 3 d Lo 27 SECTION 10 PARTS LIST CABINET ASSEMBLY Complete Cabinet 11 Music Rack Noel Hinge CHASSIS ASSEMBLY Logic Loard Assembly Voice Generator Board Assembly Control Board Assembly Rhythm Switch Board Assembly Chassis No 8 Holder No 2 Panel No 18 Knob Noe2 No 3 Rotary Switch Paddle Switch Sli
12. de Potentiometer Light Emitting Diode Badge No 21 MODEL TR 77 PARTS LIST GL 3 VG 2 OP 1 RS 3 Jazz Section _ R8 4 Latin Section for Tempo Control ESR E246R25B PW 2022 Black PW 2022 White 10K A EVA QOAAOO for Volume Control 10K B EVA QOAAOO 100K B for Tempo Control TLR 103 Touch Start Bar Voltage Selector Switch XW 103 1 10 Jack SG 7615 No 5 Push Switch KW 006 for Metronome and Fade out Knob MSA 26TS for Rotary Switch Power Transformer PT 19B C 100 1207 or PT 19B D 230 250V Power Supply Cord 3m with Plug Bracket No 2 Lemp Bracket Long Nut No l 10mm No 2 16 4mm Terminal Strip eL4P 2L5P 0 5 FRINTLD Circuit BOARDS No 8 Logic No 9 Voice No 10 Rhythm Switch RS 3 No 11 Rhythm Switch RS 4 12 Control PUSH SWITCHES LOFS 50U 85 Jazz 2F5 14U 251 Variation 10FS 54U 86 Latin DUTTONS No 4 Ivory No 5 Maroon No 6 Green No 7 Yellow No 8 Gray 28 142 003 143 002 149 001 148 003 148 004 016 002 016 003 001 006 016 010 022 019BC 022 019BD 008 013 052 008 052 009 052 010 052 011 052 012 016 004 016 005 016 006 016 007 016 008 COILS SEMICONDUCTORS RESISTORS Choke Coil 45mH Coil 40mH O TH 3 8H n 10 16 Oscillation Coil Integrated Circuit Silicon Transistor 14 ue Silicon Diode Trimmer Potentiomet
13. e A Dimension Width 640mm Highth 95mm Depth 310mm B Weight T 5Kg C Finish Walnut Finish with Hard Resin D Accessory Connecting with Pin Plug Adapter Foot Switch E Controler Start Stop UP TEMPO NOME FADZ OUT Conzrol Voice Control Volume Control Tempo Control F Others Foot Switch Jack Output Jack Pilot Lamp 1 3 Electricity A Output Max 8 0V p p Low impedance out lOKohm High impedance out 200Kohm B Power Supply 100V 240V 50 60 Hz C Power Consumption 4 9VA WOO MMT A XY X X X XX EX UO Np exco SPLCIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE 2 SECTION 2 THEORY OF OPERATION ROLAND RHYTHM TR 77 consists of four elemental sections and a power supply The first elemental section is operation system for rhythm patterns includ ing a master oscillator amp reset circuit TOUCH START and amp TEMPO LAMP The second elemental one is rhythm selector system which selects pulse patterns coming out of the operation system The third is voice generat or system and the fourth is amp udio preamplifier The Following Figure 1 shows the abovementioned Operation System Rhythm Selector System Voice Generator System Audio Preamplifier Output to External Power Amplifier Fig 2 2 1 Operation System The operation sistem is divided into master oscillator divider matrix reset START circuit and TEMPO LAMP Master oscillator is multi vibrat or o
14. e period of a standard trigger pulse is generally 0 6 seconds at UP TEMPO OFF Measure voltage of output terminal on the voice generator PCB and connect jack output Low out with an ampli fier In case of listening to sound at the same time connecting an amplifier take down the volume position not to be due to output terminal Set the percussion level control knobs Cymbal High Hat Maracas Guiro Suare Drum Bass Drum to right end on the scale Set the Fade Time control knob to left end on the scale 21 Logic PCB Voice generator PCB 3 0 10 Fig 21 amplifier Volume B Adjustment of the noise section M Cy HH SD TB GU a Adjustment of Maracas b Pig 22 d Adjustment of Snare Drum Connect amp trigger pulse with terminal M on voice generator PCB and adjust semifixed resistor VR313 so that the level of output voltage may reach 2 0V Check decay time within regular value Adjustment of Cymbal Connect a trigger pulse with terminal Cy on the PCB and check decay time and output voltage within regular value output adjuster of Cymbal is same Maracas Adjustment of High Hat Conneot amp trigger pulse with terminal HH and see output volt amp ge within regular value Check decay time within regular value High Hat adjuster for output is to do the same semifixed resistor VR313 that Maracas s and Cymbal s outputs of M Cy HH E output voltage
15. ency voltage decay time again Adjustment of High Bongo Connect amp trigger pulse with terminal HB on PCB adjust semifix ed resistor VR305 so that the level of output voltage may reach 1 5V When frequency of HB is over or under the regular value adjust capacitor C327 In case that capacitor or value is changed check frequency valtage and decay time again Adjustment of Cow Bell Check frequency Connect amp trigger pulse with terminal CB on PCB turn semifixed resistor VR303 release the higher sound CB H and check frequency and decay time of the lower sound CB L within regular value On the other hand turn semifixed resistor VR304 release the lower sound CB L and check frequency and decay time of the higher sound CB H within regular value And adjust the semifixed resistor VR304 so that the voltage of the lower sound CB L may reach O 6V Next adjust the semifixed resistor VR303 so as to make the voltage synthesized of CB L and CB H as 1 3V When frequency of the lower sound CB L or the higher sound CB H is over under the regular value adjust capacitor C316 For the lower sound CB L adjust capacitor 321 In case that capacitor or value is changed check frequency and decay time again Adjustment of Claves Connect a trigger pulse with terminal C on When the frequency of C is over or under the regular value adjust capacitor C304 In case that capacitor or value is changed
16. er LL Metallic Oxide Film Resistor 3R 4R 5R 6R 1204H KODEL TR 77 FARTS LIST 094 465 2Sc828 R Q 25449 3 GR 151850 1518508 151555 152473 10K B EVL R4XAOO 50K B EVL R4XA00 100K B EVL R4XA00 Carbon Solid Resistor 29 20 ohm 3W 68 ohm 1 2 GF 4TOohm 560ohm 680 1 5Mohm 2 2Hohm 2 T onm 4 TMohm 33 ohm 1 4 56 ohm lOoOohm 150ohm 220ohm 680ohm 620ohm l Kohm ce Kohm 3 9Kohm 4 TKohm 5 6Kohm 10 Kohm 15 Kohm 18 22 Kohm 27 Kohm 33 Kohm 39 Kohm 47 Kohm 56 68 Kohm Oc LOOKohm 150Rohm 180Kohm ecOKohm MFC 6040 or SFC 6043 25C1000 GR 256372 022 030 TR 77 PARTS LIST Carbon Film Hesistor CAPACITORS Electrolytic Capacitor n Ceramic Capacitor LET Plastic Film Capacitor Tantalum Capacitor 270Kohm 1 4 330Kohm 4TO0Kohm 820K ohm 1 Mohm 1 4 1 10 33 41 100 100 100 1000 15 mfd mfd mfd mfd mfd mfd mfd mfa mfd pfd 50V 100 pf 50V 250 50V 410 50V 001 001 002 002 003 004 005 006 008 01 015 022 021 033 039 041 056 068 082 1 22 33 mfd omfd enfd 3mfd mfd mfd mfd mfd mid mfd mfd mfd mfd mfd mfd mfd mfd 037 002 031 006 037 007 035 001 35V or 25V 032 094
17. f two transistors Tempo is controled by adjusting bias voltage to the oscillator which is three potentiometers of series connection One is the slowest tempo and the other is the fastest tempo The an other one which is fixed on the control panel is used by a player for adjusting a very delicate tempo Divider is 5 stage transistor flip flop counter set for dividing a beat cycle into 1 32 cycle of the master oscillator As a 3 4 beat rhythm must be necessary the second and third stage divide a beat cycle as the unit of 3 instead of 4 with feed back between the output of the third and second stage of the dividers The output of the stage four divider is supplied to the base of the transistor for lighting up the TEMPO LAMP The TEMPO LAMP will light up to the first beat But only for SLOW ROCK and BALLAD rhythm light will come on the first and third beat The control of brightness is adjusted in advance on light up time For the TEMPO LAMP light emitting diode is used Output of divider are connected to the diode matrix which is taking pulse patterns Various pulse patterns are used as a trigger of voice generator Touch switch consists of radio frequency oscillator detector flip flop and part of oscillator connected to Touch plate on the control panel When this plate is touched with hand oscillation will stop and this voltage fluctuation is used for trigger of flip flop and so rhythm will either stop or start s Up Tempo Switch
18. ic circuit consists of radio frequency oscillator bufferamplifier flip flop and oneshot Radio frequency oscillator works regular oscillation The output of oscillator is added to the base of bufferamplifier after _ 5 2 6 2 1 2 8 it is rectified When you touch the touch plate mounted on the control panel the oscillator stops oscillation The voltage that was rectified minus comes up to O This rise up voltage moves the bias of buffer amplifier and let it turn on The collector voltage of bufferamplifier is used for trigger of flip flop and the output of flip flop is used for trigger of oneshot The output of transistor usually in the turn off state is connected with the reset terminal of Logic board While this transistor turns on time between 20 and 30mS master oscillator and divider are reset Because they are set immediately after turn off they count from the lst beat Start Switch Start switch jack mounted on tha rear side of rhythm unit is connected with the terminal RS of control board assembly Start switch is used substitute for time switch When the start is placed ON or OFF flip flop and oneshot can work ac cordingly Metronome The metronome is generated by amp phase shift oscillator which decays ex potentially Frequency is adjusted by potentiometer The metronome switch is used flip flop trigger Fade out When the fade out switch i
19. including Cymbal High Hat Snare Drum and Guiro The signal affects tuned amplifier after passing the required envelope circuit This time it is compounded with WHITE NOISE signal The output from the tuned amplifier moreover adds to the preamplifier Quiro is cscillated ty outputs for trigger matrix exclusively made from the diode matrix outputs different from other outputs The other different kind of signal comes into the base of the transistor works the multivibrator composed of two transistors and oscillates the diode matrix outputs more closely This multi vibrator makes out the eff icient percussion sounds of Guiro itself The frequency of the multi vibrator comes from the bias adjustment of amp semifixed resistor for providing beforehand The output of the multi vibrator feeds a tuned amplifier with WHITE NOISE signal And this tuned amplifier is the narrow band amplifier and the output passing this amplifier comes into the preamplifier Audio Output Both the signal of amp high frequency teritory and that of low frequency territory are added to the preamplifier The outputs feed to the volume control fixed on the control panel Moreover 1 feeds to obtain out puts of the full auto rhythm instrument through the buffer resistance Preamplifier consists of 3 parts of amplification the 2nd of which is IC of Electronic Attenuator for the fadeout Touch Switch Touch switch circuit to reset log
20. l I I TLR 103 5 56 Tar 4 7 Joo LO R60 J402 5 VOLUME gt R sI f Ben 3 10 10 4 24 36 x GNE E ye ae OSA FUSE L eya bo MOG2 RS 1 VARIATION Is CONTROL BOARD 1 M E601 RHYTHM SW Ari C RCUIT DIA 409 001 CIRCUIT DIA bod 324 0 _ 1 BD Fig 1 RHYTHM SW CRS 3 SHORT C60 5601 5402 2 Me a 2 24 v vreo 2 GENERAL BLOCK DIAGRAM FADE OUT TIME ncn AC 50 60 SECTION 1 SPECIFICATIONS 1 1 Summary Rhythm Jazz Section Rock n Roll 1 Rock n Roll 2 Slow Ballad Western 6 8 March Jazz Waltz Waltz CANCEL Latin Section Rhumba Beguine Cha Cha Mambo Samba 1 Samba 2 Baion Bossanova Bolero Tango 2 Beat Variation Bass Drum Bass amp Snare Drum Fox Trot 1 Swing 1 March Parade 4 Beat Variation Bass Drum Bass amp Snare Drum Fox Trot 2 Swing 2 Swing 3 Shuffle B Voices Bass Drum Low Conga Low Bongo High Bongo Cow Bell Rim Shot Claves Snare Drum Maracas Cymbal High Guiro Tambourine C Voice Control 1 Cymbal High Hat Maracas 2 Guiro 3 Snare Drum 4 Bass Drum D Tempo of Beat 12 130 Beats Min Number of Active Elements Silicon Transistors 41 pos Silicon Diodes 175 pcs Light Emitting Diode l pce IC l pce 1 2 Apperranc
21. m Ensemble Pattern Fig 12 4 T r w 0 2 4 b Q ww m 22 m m 39 9 I FOXTROT 1 creso us BD a us N 4 PARADE ma FOX TROT 2 8D ca ERE TIEN lt SWING 3 cr SHAFFLE 92 90 190 19 9 0 190 160 0 2 b B 1 12 14 16 20 22 24 25 28 30 32 15 CY BD LC LB 0 IN 10 8 7 6 Ue ma FC Board Assembly VG 2 Fig 13 RS G Layout Parts SECTION 7 VOICE GENERATOR CIRCUIT 1 1 Voice Bye e E ds a X die aput Em oh x R Y RE ee a LE Bv ace SIL TX mes EM d pus a Ne qur osse iet de ro est 9r s iz TB HM oo 99 9 0 4 G B LC 8 H8 R E BD S 555 132413 28C 372 Y 66 R 1555 2 C 10 CD ollector and 0352 soldered on rear side ef of Q3 9 the board between base b voice Gert Circuit Diagrem VG 2 Fig 14 302 C303 C305 D301 S 00 001S C304 30 947 orm 99471 i T00mH R305 0302 100K C312 C307 89942 3 7 C310 1302 001 47K oy 8307 C315 TomH D303 095 2317 001 R310 34K vR 303 50K B R309 D
22. ollector of Master oscillator Seeing the wave form on the collectors of 61 and G2 and check the wave forms whether they are as Fig B undesirable wave form includ ing unsaturated territory In this case it is necessary to use the oscilloscope of which input impedance is not less than 5000K Ohms _ 37 5 300 mS not saturated territory Fig 18 E For symmetrical the wave form of output of the Master oscillator The wave form on the collector becomes not to be symmetrical because of instability of the circuit constant of the Master oscil lator This circuit constant is set as following mention and adjust it by changing the capacitor Cl or Ce Tt T 20 C 1 L Te Fig 19 When the UP TEMPO switch is set ON check the tempo speed to be double despite the place of the tempo volume In case that oscillo scope is connected with logic output terminal T the period of pulse observed becomes to 1 2 9 2 Adjustment of Tempo lamp See wave form amp t the logic board terminal L by the oscilloscope and adjust semifixed resistor as to get the lighting time of the light emitting diode 60 5 T 20 Fig 20 5 9 3 Voice Generator A Adjustment by measuring wave form on the oscilloscope Logic output terminal 3 pulse track No 3 negative pulse is a standard trigerpulse adding input terminal of each voice generator except Guiro s Th
23. s connected with the voice generator Buttons of WALTZ JAZZ WALTZ SLOW ROCK BALLAD and BOLERO provides for the circuit to feed back on the divider for making 3 4 beat The diode connected with the rhythm switch helps the diode matrix and keeps away from affecting JAZZ and LATIN rhythms to each other Voice Generator ROLAND RHYTHM TR 77 has 13 voice generators including Bass Drum Low Conga Low Bongo High Bongo Rim Shot Cow Bell Claves Snare Drum Cymbal High Hat Maracas Tambourine and Guiro Each of Bass Drum Low Conga Low Bongo High Bongo Rim Shot Cow Bell and Claves oscillates by electrical input pulses given to each L C resonantly circuits 97 necessary frequency and index decayed oscil lation Drum sound of Snare rum has a buffer amplifier by transistor in addition to L C resonantly circuits and likewise oscillates For 2 4 outputs potentiometers may be set in order to control the output level Cow Bell is combined with binary different frequency oscillators The outputs of these L C resonantly circuits are coupled to audio pre amplifier The transistor reversely biased provides the basic WHITE NOISE which is generated in Cymbal High Hat Maracas Snare Drum and Guiro The output of noise generator is given to the first amplifier and three semifixed resistors are parallelly connected with the col lector load of the amplifier They used for adjusting the output level of treble sound
24. s pushed condenser of CR Time Contrast is earthed At this time the resistor of CR Time Contrast is connected with the base of PNP transistor The emitter of this transistor is conneoted with the control input of electronic attenuator mounted on the voice generator board assembly SECTION 3 GENERAL NOTICE 3 1 Avoid playing near the fluorescent light neon light transformers etc amp 8 they will create undesirable noises 3 2 It is absolutely free from sound distortion but it should be played Within the capacity rating of the amplifier It is always advisable to connect to amplifiers having ample output power 3 3 Since it covers very wide range of tones the quality of tones may very according to the types of amplifiers used Use any amplifiers having high selective qualities 3 4 Avoide using RHYTHM ROLAND in high temperature and humid places also remember that accumulated dust will take damp SECTION 4 DISASSEMBLING When disassembling the cabinet remove wood screw on three point of rear Side and six point of the bottom with amp screw driver Loit Circuit Diagram 61 3 Pig 4 gt iy 5604 GaP LIGHT EMITTING LAMP m TLR 103 TOSHIBA RE 470 2 Jim 47 151555 ALL RESISTOR ARE IN OHMS 1 4 ALL CAPACITOR ARE UNLESS OTHERWISE SPECIFIED ALL TRANSISTOR ARE TYPE 25 828 or R ALL DIODE ARE TYPE Tantal
25. um Capacitor NOTE 37 5 300 mS ADJ Siow ADJ 470 Yow a Fi e Q O Q 2 Maske OS C 92 5 1 Logio Matrix Board assembly GL 3 SECTION 5 LOGIC CIRCUIT 3 Layout Fig Parts Goo C 09855209 Ge d MN 4 v MN 0880089 gong 0009000 000000 DR 00000 0 0 0 00 0 02000 00000 0000000 00080 01 Wood 060000 00000 96027 UNU 05090 OCO O o 8000 525 S e e NEEDS imo Roa AW MT OOO O O t Tantalum Capacitor 25020 46 137555 039 00 84 D UNLESS OTHERWISE SPECIFIED 270K lt lt lt lt 8 9 1 ll 72 D 4 5 ib 02021 232425 2627 26 31 33343530 37 38 4 40 40 42 5 2 Metrix Circuit 0 0090000000090 A Circuit Diagram Fig 5 u m na LEUTE 55 vr ZT xw eem v wl oN pe 01001 gt LH 257 per paz pu LI dL DTE s s ese sss ese per je el TE 01051 77 T
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