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About This Manual and Servicing The Prophet
The Prophet Is asophisticated instrument and SCI issues its technical manual for use by qualified
technicians only. Of course the manual will be read by Prophet owners and others Interested in
synthesizer design. And we realize it will also be used by some to develop modifications for the
instrument. While we support this innovative attitude in spirit, we cannot support it financially:
Modifications or unauthorized service void the Prophet's warranty. They also invariably extend service
time (thus, cost) if factory repair is required. Familiarize yourself thoroughly with this manual before
attempting any work on the Prophet. This will at least help you judge whether you should be working
on it at all. If in doubt, please contact our Service Department.
This edition of the Technical Manual (TM1000D) documents Prophet-5s with serial numbers 1301 and
above. Although great care was taken to ensure the changes would be transparent to players,
technicians will find "Rev 3" quite adifferent instrument from its predecessors. Rev 2(S/N 184-1299, see
TM1000C) was amere refinement of Rev 1(S/N 1-182). Rev 3, however, uses new voltage-controlled ICs
in the analog synthesizer and, in the microcomputer, avastly different ADC, DAC and control voltage
distribution scheme. Although the main purpose of the revision was to remove production limitations
caused by inconsistent supply and quality of the previous synth "chip set," the hardware redesign
encouraged the implementation of more sophisticated editing, tuning and maintenance software while
improving servicability; the number of voice trimmers being reduced from 80 to 45.
The manual is organized as follows:
SECTION 1, MECHANICAL provides aphysical introduction and directions for
disassembling/assembling the Prophet.
SECTION 2, THEORY explains general function and circuit operation, referring to block diagrams and to
the schematics for hardware details.
SECTION 3, DOCUMENTS contains schematics and pictorials identifying all components.
SECTION 4, SERVICE contains procedures for routine tests and trims.
SECTION 5, PARTS cross-references component designators to SCI stock numbers.
SECTION 6, GLOSSARY decodes abbreviations appearing on SCI documentation.
SECTION 7, APPENDIX contains selected data sheets.
Your response to the questionnaire on the next page will help us monitor our publication's usefulness
About The Second Edition
In addition, to the original revision 3.0 data (with afew corrections), the following
material covering later refinements of the instrument has been added. The revisions
occured chiefly in the microcomputer's memory configuration, added PITCH and MOD
CV inputs, and in the addition of aserial interface for communication with the Model
1005 Polyphonic Sequencer or Model 1001 Remote Keyboard.
SECTION 8, THEORY discusses the hardware changes comprising revisions 3.1 and 3.2.
SECTION 9, PROGRAMMING covers use of the serial interface.
SECTION 10, DOCUMENTS contains schematics and pictorials for revisions 3.1 and 3.2.
SECTION 11, SERVICE includes instructions for updating a3.0 or 3.1 instrument to
level 3.2, for using the diagnostic memory tests, and for an added adjustment on
PCB 3.
SECTION 12, PARTS lists SCI stock numbers for 3.1 and 3.2-level assemblies. D.2
