Casio_DH-500_Digital_Horn_Service_Manual电路图.pdf

《Casio_DH-500_Digital_Horn_Service_Manual电路图.pdf》由会员分享，可在线阅读，更多相关《Casio_DH-500_Digital_Horn_Service_Manual电路图.pdf（42页珍藏版）》请在收音机爱好者资料库上搜索。

1、J )I I I SERvrcE MANuAL | .t,r l. r I tit- 1 r i i i I I l i li I t t fI I 2 t t z ctat r-rF-t l-l s+ris$f 1 f I r l t I =i +F rtl rG?rF I F Ftrd I Elr rrrrY I l . i l . # n iiu I L: F I ! I tCt ,c T I I tn E u TI ; l I . J e B RAM _ i, F crot r-r l + c ? FO D6 rt? rt 16MHz Oscillator c r T d rH or

2、l.ol r f n 4 9 o : tc! ttro.ctar lc3 n l rh 6 EEaisEs$iE!ii; IC3 t,1866il31 TOP V IE|/ I DSP lm tvrl rrt TE rva lrt 6 G - ttt ; l ! | t t a r !c - !a ng $r tt0 :E o. ot # o l l l l*s cry l -11-; ra (c i, (tt-,3 I - /l* j H J rrrrr-orI 3iF fn r=j- ,., ll | ,*,.- | u l | | t t l | -r- -1 fn t It Ll EL

3、-Vr0ot(R-l L2 EF 05t30t-56FZt03I F8 q-02Ri?-R6? -t- F bi QA 1tl 5t oae ffiE=-f i I I I : i nt fyioesnJ l-?+- I + tIItl l l tatS-raol lft, Ifi, fl5 rxf l i n8 - latt purfos pelqoo m !( c-taB iatufst-ltt t tgAlll I 3 a1 aa rF I tL, , i, tz) f r 5 punos Fulopo qDssrr.rr I It ; :.: v,t;,:V ut - (E E s L

4、rl . ./ I /El I Jl .-l t, PcfF:t-1-crtr-l I I I tjEfrcE:nftiJ I I i nFrl_JJ llF:T:KjF:i-l-ttfl I i EE:IGil | | frF-j-1TF-:TTtEl I i uF:i-l.lEtr.r-T.Ei_1, I Dri-KfF:g-lEFt tfF.T-rfr:6-reEr-l rt I f,l BE EI E f vrgnrro I l-or-l f-orl-_l 11xrrsq mcsal Frnrtr.nol f-!ejs-l fcaRui-l fTur-. -:nlJ-rfi i.Tr1

5、lf:rrrir11.1;9.: 5. i;al r.lr-?;:.:;.; PCB VIEW . l t ,:.: : l.:- i.dfr ,:r= Itl-: -_- 1L ,.ri: i , . ,i c s iI 1., ! si a-. s . rF xr; ! 1 t l Il-l I nr! cHl .2v trL Pitch sQnat PC6 lC13 pin 17 Tone: Saxophone, No key press Sampling Clrcuit Input lC7 pin 1 Tone: Saxoptibne, No key press Sampling Cl

6、rcuit output lC7 pin 7 Tone: Saxophone, No keypress t tt I I d $ ffitln :L,:!. Tnfiar Oboe; No key press plfol.e/To6 ciibuit oiiipil , , lC9 pin t , olcz output ICB pin 1 Tone: Saxophone, Nci key piuss i A il L*.irrrc/ |A,*fl|cr*,4 n,.*,*l V Clt|eO.9ort r- I cxl20rv o220-v F*,nr r ti U .t tJl v IAG

7、I t 2ro cHt . ? 0rt MAJOR WAVEFORM o o o Reset stgnal lCl4 pln 6 Al Power ON Pilch slgnal PC6 1c13, pin t7 Tone: Obo, Nokeyprsss A 5pa rAC ; cxr . aVorl Rpverb Mute sQnaf lC 13 pln 15 AT Power ON vcF ouqrr l0l1 pin I Tone: Saxophone, No key press I i cxr i I I I : I t I I o iL- , I cHl cl tu cxr . a

8、V 8t- l-,I|* lrr lL Clll ZOIY 8A orr . a? cH? . ev (D BLOCK DIAGRAM Main Volume o o o Orlginal sound Sample/ Hold Circuit PF4,PF6,PF7 o BSHH Dlgilal Snal Processor M8661131 i I . . t I I . . I .: Breath Sensor block outputs voltage whlch conesponds to the strength of breath. Uslng a built-ln ADC (An

9、alog lo DigitalConverter), the CPU digitizes the voltage levellrom Breath Sensor and outputs the digitized data P0-P7 lo DAC (Digital to Analog Converter) 1. On the other hand, CPU detects pressed keys and provides conesponding sound slgnal PC6. The sound signal is amplified and liltered in VCA (Vol

10、tage Controlled Amplifier) and VCF (Voltage Controlled Fllter) whose anplitude and cutoff frequency depend upon control voltage from DAC1. DAC1 converts the digitlzed data P0-P7 into a voltage levelwhich becomes control.vg$ggflf VCA and VCF. Thus, the gound ouput PC-6s volume and cutotf frequeLcJt_g

11、19_-vadeilln accoiital Signal Processor) and stored in the HAM. Changing the reading speed ol RAM dala, the sound data is delayed, DACd,llllered, ard mixed with the orlginal sound in Mlxer. CPU pPD78C1lG DISASSEMBLY : ri. ., 45-48PF4 - PF7OutPF4, PF6, PF7 - Tone control signal in VCA (Voltage Contro

12、lled Amplifier) filter. ln accordance with set tone, the voltage level of these terminals change the cutoff frequency of the sound. PF5 - Resonance control signal in VCF (Voltage Controlled Filter). When the terminal is Low, resonance effect is given to the sound. TonePF4PF5PF6PF7 SaxophoneLowLowHis

13、hHigh TrumpetHighLowHighLow Synth. ReedLowHighHighLow OboeLowLowLowLow ClarinetLowHighLowLow FluteLowHighLowLow 49-55PDO - PD6 OutLED drive signals 56PD7OutAPO (Auto Power Off) signal. When the horn is not played for six minutes, the voltage of the terminal drops to Low level causing the voltage VCC

14、 (+9 V) to shut off. 57STOPNot used. Connected to VDD 58VDDln+5 V source 59-2PAO - PA7 OutDigitized breath strength data ;sa 4 2 6 LC Oscillator VAD (+5V) r-1 cPU ., , pPD78c11 ANO Reference Voltage Generator o BREATH SENSOR BLOCK Weak breath - -;,-. I = lll9ll ; v=low Rectifier : A . i - , . . . 8)

15、,Relerence Vottage i Generator comparator VAD (+5V) ,1 Q5t le5 . . An oscillator which is composed of a coil and capacltors. As the core in the coil moves by the breath, inductance of the coil varies by the blowing strength. Variation of the induclance changes the frequency and peak to peak voltage

16、of the oscillation signal. Namety, when the breath is weak, osoillation trcque.hcy is high and peak to peak voltage is low. ,i On the contrary, strong blow lowers the frequenry dnd heighten the voitage. Strong breath f =low ., v; nbfr, Atterthe oscillation signalinto a DC voltage.*Strongerthe breath

17、, higherthe output voltage. . . . Compares the Rectifier and Rbftlience Voltage Generator outputs. i When thb instrument is not blown, the output vbltrage-olOlixparatorls,zAro volt. The output voltage riscs in accordance with the breath strength. ,4 *t- -13 - i i ji ffr; ffi ffi iiil:i ri.,ji I_ ,r-

18、,.- Refernce Vohage Generator x; ll lr,/ lr./ lr,/ ty .r1., No Soft Strong Breath DAC 1 CPU digitizes the input voltage level from the Comparator. Since the variation range of Breath Sensor Block is too small, the CPU amplifies the breat strength data digitafly. Digital breath strength data PAO - PA

19、7 is conveded in a voltage level by DACl which is made up by resistive ladder network. The output voltage of DAC1 is provided to VCA and VCF. Breath Strength Strong PC6 DACl i sorc PA2 ; VCA (Voltage Controlled Ampllfler) In accordance with breath strength, the VCA changes the sound volume. VAD (+5V

20、) To VCF HighPass Filter To VCF Ip-:- - In accordance with pressed keys, CPU generates pitch signal PC6 which enters transistorT6. As the collector of T6 is connected to T5 emitter, amplitude of T6 depends on T5 base voltage. Thus, DAC1 output voltage (i.e. breath strength) determines the volume of

21、pitch signal. VCA atso consists of high pass and tow pass filters. According to the set tone, CPU provides signal PF4, PF6, or PF7 which SEtect the fitters cutoff frequency. The following shows an equivalent block diagram of VCA Circuit. Equivalent Circuit 52, S3 :.:,:, i,:,.r,. i;l;i;i: l : ;|. . l

22、: i: i: i t:-t !. il;c iiii, l:;. :, -. i. l., i ; PA7-PAO tt TL Low Pas Pitch signal +5V - 15- The left figure is one-stage low pass filter whose cutoff fre- quency fc depends on lhe capacitance C and the resitance R. 1 lc= 2rCR using a variable resistor changes the cutolf frequency fc randomely. F

23、ETs (Field Effect Transistor) have a characteristics that the resistance belween source and drain varies in accordance with gate voltage. Vg=high. Rsd=small Vg=|ow. Rsd=large VCF (Voltage Controlleo rllfffl Outffiln cR h Flg. A out*rn iR Flg. B Vg T Gate Source T-JT- Drain Rsd Flg. G Therefore, putl

24、ing a FETinstead ol avariable resistormakes the same circuit as figure B. Ftg. R Since the FETs gate voltage is provided lrom DAC1, the cutoff frequency varies by the strength ol breath. Namely, stronger the breath, higher the cutoff frequency. Weak breath T T Strong breath The actual VCF Circuit is

25、 a four-stage low pass filter which makes sharp drop of cutoff frequency response. T5 25C24r2t(R - I f t 6 sE x (t G AC AC vAo tA4558Fx n/2, from DAC1 ln from VCA 8A4558F-OX lt/21 r ! l oi- O + ( J l I I l , t t I A G Out T3 2SKL2S ID c! (J IL 2SKL25 B gis ! ,0,n RLL cr0 tJ IF c30 t0r R6? -+ ct0aF -

26、F J3l I rt CE I I I - -N -J feed back The switch S tums on orotf by. signal PF5 from CPU and controls the resonance effectwhich is given by leeding the ouput sound s4fnat of tbF back t6ine iriput. Whgn signal PF5 lqm CFU is Low, th-b- swifch S turns off causing the VCF ouput fed-back to the input. l

27、f PFs is High; the swilch furns on sendi.ng the VCF output sound to tne last stage of the filter which minimize the resonanceeffect. lF I R(9 I Llf ! lct2 ) 8U40668F ll/al PFS from CPU i :ts 5+E l i*E H r m m A c v A o l Ao c | - Minimum resonance $iii;:*a$;*qir# Address Bus REVERB EFFECT CIRCUIT Mi

28、xer , Delayed y sound /t n- -J V -n-3125 kHz Sample ruLflftfln_ : M 11,.:.-; t , : Mute CircuitSarnple/Hold Circuit VCF output sound signal is digitized in built-in ADC in the DSP with sampling lrequency of 31 .25 KHz. The digital sound data lrom built-in ADC is temporary stored in the RAM. The stor

29、ed datain RAM is read by DSP (Digital Signal Processo0 and re-formed in a waveform in DAC2. At this lime, DSR changes the reiding sieed by viring address signals frequency in order to delay the sound signal. Since DAC2 output isstepped waveform containing glitch noise, Sample/Hold Circuit removes th

30、e glitch and Filter smoothes the stepped waveform. . When the horn is not blown, CPU turns the FET off by signal PC4 to cut the sound off. .:. Reverb effect is given by adding VCF output and delayed sound. PC4 trom CPU n n | ,t vv r-|/ t- = jcc -,:.o i , . F i I , DIGITIZATION SAMPLftE CIRCUIT Sound

31、 waveform lrom VCF enters the DSP with 31 .25 KHz sampling frequency. DSP (M8661131) coMPr y RV15 - RV4 To DAC2 DO-D7 32trs i S Sampling Circuit .,ffi. DSP (Dlgltal Slgnal Processor: M8661131) PIN FUNCTION Pin No.Terminallr/OutFunction 1,2, 4-9DT7 - DTOlrVOutData bus between exlernal RAM M865256 3VD

32、Dln+5V source 10MMODlnExtemal RAM selection terminal. High. StaticRAM Low.DynamicRAM Connecled to High level 11. 12CLKO, CLK1lrVOut16 MHz clock pulse inpuVoutput 13RESETlnPower ON reset signal input. Low action 28VDDln+5V source 40VSSlnGround (0V) source 48-52 54-60 RV4 - RV8 RVg - RV15 OutDigital s

33、ound data output. Sound waveform from pin 66 is digitized in the built-in ADC and output lrom these terminals. 65VSSlnGround (0V) source 66CMP IInSound wavelorm input 67BSHHOutKHz pulse for Sample/Hold Circuit 68BINHOutKHz sampling pulse for built-in ADC 70CLKPOutI MHz (16 MHZJ2) clock pulse output.

34、 As direct touch of oscilloscope probe on oscillator may stop the oscillation, this terminal is used for clock pulse checking. 72-75RVTO - RVT3 InReverb time determination terminals. Reverb time is determined by the vollage levels of these terminals. 78VDD2ln+5V source 91, 82 85-89 91- 94 96-98 100

35、AD14, AD12 AD7 - ADs : ADgrr ADg ADz - AD1 ADO OutAddress bus for the extemal RAM. Stored data in RAM are read in various delay tirheby vditngH6l6fe$s signals ti,-; ,1: ri.;1,.,: ,.,. : 84WRITOutwrra aiur ii sid i%i ; ,r/hdif f bffi , Bifi iiidso u nd data are written in RAM. 90VSSlnGround (0V sourc

36、e) 95EOUTOutOutput enable signal. When Low, the RAM outbuts stored data. I R4q:l=rr-j: SAMPLE/HOLD CIRCUIT ?AC output waveform is a stepped waveform and contains a thin noise called glitch in each step. Sample/Hold circuit eliminates lhe glitch noise. BSHH trom DSP / i Enlarged VADl (+3V) DSP output

37、s a sampling signal BSHH in each step of the DAC2 output. while signal BSHH is High revel, the switch s lurns on causing the signal to pass through. At the same time, voltage of the signal is charged in the capacitor C, At the end of one step where the gtirch appears, signal BSHH falls to Low level.

38、 The switch s turns otf shutting td glitch out. ryryF swilch turns otf , capacitor c discharges so tnat tne output of-lhe switch keeps the same voltage tevet. Thus, the glitch noise is eliminated from the DAC2 output. FILTER, POWER ON MUTE, MTXER CIRCUITS The stepped waveform is smoothed by,the Filt

39、er. At Power ON, cPU ri99s the signal MUTE turning FET T7 off. The power on reverb noise is etiminated. Delayed,sound:sighal from DAC2 is then mixed iitn tf,e VCF outpui by Mixer. :.: _-.t- dl Mute fbm CPU , ?,xr From Sample/Hold Circuit ,arr*-or ! avlt u itr ? I iJ3 U Serg5att.gt trrrl I t t Fifter

40、 -21 - Delayed sound t/L $/ DAC2 DAC2 consists of inverters and resistive ladder network and reforms the digitized data lrom DSP in sound waveform. The followings explain the digitalto analog conversion method EXK-F1922064 +5 In the left figure, if the current I from the battery is 1.5 Al, it =0.8 I

41、Al, i2 =0.4 A, R =0.2 Al, and i4=0.1 Al as they passthrough lK, 2K, 4K, and 8K ohm resistors respec- tively. When all the switches are OFF, the output cunent /o is 0 A but, if switches 51 and 53 are ON, the output current will be; lo=iI+ig=1Al lf all the switches are ON; lo=il +i2 +i3 +i4= 0.1+0.2+0

42、.4+0.8 = 1.5 Al Thus, digital action of switch ON/OFF is converted into analog amount of the current. Actually, the DAC in DH-500 is made up by inverters and R-2R ladder network. Instead of switches, being High or Low of DSPs digital sound signal determines cur- rent flow. For instance, when signal

43、RV15 is Low, the inverleroutput becomes High caus- ing the current il tobeflowed. lf RV15 is High, the current does not flow. Since the DSP output current is too smallto drive the DAC, lhe inverters amplify the current. R-2R networked resistors halve the cunent in each ju rrction. For example, suppo

44、se current 7 is 10 mAl, i2 is 5 mAI, i3 is 2.5 mAJ. Therefore, each bit of DSP oulput has significance. Namely since lhe circuit is 1 2 bit DAC, cunent f fow from terminal RV15 is 2048 times larger than the current from RV4. The output cunent /o from ladder network is transformed in voltage level by

45、 the op amp lC8. l-l | *ir I R Fl =25Ktl Fl zR=soKe 8Ko ga 6-oN DSP M8661131 RV15 t/ | 2R RV14 r/ I 2R RV12 L/ x lzR RVl1 t/ l2R l-l I nl I nl I Rl I R. .i I nl *l J : . . j l:i -22- ,/ ; KEY AND SWITCH MATRIX PORTAMENTO B D$ K _=_L (Octave up) (Octave down) F H J ii PBOPB1 PB2P83 P84PB5 P86P87 PC1

46、GH1# JOBOE CI.ARINET FLUTE PC2 FEb D#CSAXG. PHONE TRUMPETSYNTH. REED PC3PORTA- MENT OCTAVE UP OCTAVE DOWN AB VIBRAT ON THAMS. UP TRAMS. DOWN A c Eb G -23 - ADJUSTMENTS 1. 2. Insert a silicon rubbertube (code No. 69147972,into the mouthpiece as shown on page 10. Tum VR51 on PCB MA3M as shown on the f

47、igure below. t+- vR51 N l_-/ | 45 3. Connect a digilal vollmeter between testpins TP1 and TPZ. 4. Blowing air strongly from the tube, adjust VR52 so that meler reading is 2.6V t 0.05V. 5. While it is not blown, adjust VR-51 for the meter reading; 1.00V + 0.05V. 6. Repeat the above procedures 4 and 5

48、. : _ i . r:r :. -24- TROUBLESHOOTING TABLE TroubleFaulty BlockCheckpoint No Powr ON (TUNING lamp does not light at all) Power CircuitT1 collector voltage (+9V) T4 emitter voltage (+5V) T5 emitter vottage (+5V) Power switchSwitch contact Power jack CPU (pPD78C1 1 G-18)Pin 56 (Should be High) No soun

49、d at allReset CircuitRefer to wavelorm O 12 MHz Oscillator cPU (rc13)Pins 59-2 should output pulses when the horn is blown. Pin 17 should output pulses When rtA blown (Refer to waveforms (4) and (5) ) VCA Circuit VCF CircuitWaveforms ano . DAClT5 emitter voltage should rise when the horn is blown. Power Amp (LA4182)Pins 2 and 11 should output waveforms when