Sequential prophet 5 - Sd211 Control Panel-Pots

Interconnection has been minimized in the Prophet by implementing the microcomputer system
and analog circuitry on only two PCBs. PCB3 contains the CPU, MEMORY, MEM DCOD, I/O DCOD,
ADC. DAC. COMMON ANALOG circuits and the parts of the CV DMUX which distribute the 26
common CVs.
PCB 4 contains the CV DMUX for the five KEY and ten BIAS CVs. TUNE MUX. VOICES 1-5. and AUD
OUT circuit. So signal inputs through W703 60-wire ribbon include: 1) COMMON CVs. including
W-MOD. 2) All voice switch (S) commands, 3) VDAC. for the INDIVIDUAL CV DMUX, 4) INDIVIDUAL
CV DMUX ADDRESSES. 5) GATES. 6) VOLUME CV. from PCB1. PCB4 sends the -TUNE MUX signal
back to PCB3 over W703. and AUDIO OUT over coax to the BACK PANEL.
2-18 SD211 CONTROL PANEL — POTS
There are two non-programmable and 24 programmable pots divided between PCBs 1 and 2.
RIOS, VOLUME, is not programmable.-(Its knob is silver-colored). U381 originates the 5-V analog
source to R105 through P301/J710-13 to shorting jack J707. If external dynamic control such as a foot
pedal is used, it — instead of U381 — supplies CV through R105. But, normally, ♦ SV(A) reaches R105
through J710/P301 -15, J301/P201-3 and TB201/101-34. The CV set by R105 crosses PCBs 1, 2, and 3
before buffering by U498-7. which drives U497-15 VOL VCA.
Neither is R104, MASTER TUNE (MTUN) programmable. (Also a silver-colored knob.) It offsets the
OSC A and B MASTER SUMMERS (MSUMs), allowing over a semitone of flat or sharp correction. The
MTUN signal is summed with other pitch-changing signals by U365-7.
The remainder of the pots are wired to the POT MUX; those on PCB1 through TB101, W701, and
TB201. TABLE 2-0 shows the data latched by U210 to select each pot. The bits Ql. Q2. and Q3 have a
decimal value of 0 - 7. Applied to the A, B. C control of U201/02/03. they select 1 of the eight corres-
TABLE 2-0
MUX
CHIP
EN
DESIG NAME
Q6/
/DB5
QS/
/DB4
Q4/
DB3
Q3/
DB2
Q2/
DB1
QV
DBO (HEX)
U201 R213
GLD 0
1
1 0 0
0
18
U201 R210
OSC B FINE
0 1 1
0 0
1
19
U201 R203
OSC A FREQ 0
1 1
0
1
0 1A
U201
R209
OSC B FREQ
0
1 1
0
1 . 1
IB
U201 ' R208
LFO FREQ 0
1 1 * 1
0 0 1C
U201
R212 W-MOD SRC MIXO
1 1 1
0
1
ID
U201 R202
P-MOD OSC B 0 1 1 1 1 0 IE
U201
R201 P-MOD FILT ENV 0
1 1 1 1 1
IF
U202 R101 FILT CTF
1
0 1
0
0
0 28
U202
R103 FILT ENV
1 0 1
0 0
1
29
U202
R206 MIX OSC B
1 0 1
0
1
0 2A
U202
R211 OSC B PW
1
0 1 0 1 1 2B
U202
R205 MIX OSC A
1 0 1 1
0 0 2C
U202 R204
OSC A PW
1
0
1
1 0 1 2D
U202 R207 MIX NSE
1
0
1 1 1 0
2E
U202
R102 FILT RES 1 0
1
1 1
1
2F
U203
R106 FILT ATK
1 1 0
0 0 0 30
U203 R107
FILT DEC 1
1
0
0 0
1 31
U203
R108 FILT SUS
1 1
0 0 1 0 32
U203
R109 FILT REL
1 1
0 0
1 1 33
U203 R110
AMP ATK
1
1 0 1 0 0 34
U203 Rill
AMP DEC
1 1
0
1
0
1 35
U203
R112 AMP SUS
1 1
0
1 1
0
36
U203
R113 AMP REL
1 1
0 1 1 1 37
2-21