Sequential PROPHET-600 - 2-5 SAVE TO TAPE

22. H old a chord. Switch UNISON TRACK up. Chord will now track lowest note played.
Switch off (down).
23. Vary the GLIDE knob and verify function. Leave set to 0 or select low-glide
program.
24. Check that the FILTER CV IN input operates on all six voices.
25. Connect the free end of the MIDI cable to MIDI IN. (It is not necessary to switch
power off.) Playing one key should produce two voices (which may actually be difficult
to discern). Hold a key and while holding, disconnect the MIDI cable. Release the key.
One voice should drone on. To clear this drone play six keys simultaneously.
1-2 VOICE TESTING
To test the six individual voices, throughout the following tests you must play six.keys,
or use the sequencer (not arpeggiator) to play them. The following keyboard fingering
is recommended as a habitual way of always covering six notes: 2-1-2-3-4-5. All .tests
are performed by ear, the object generally being smooth knob functions, clean switch
functions, and consistency between the voices. Note that it is normal for the knob$ to
achieve their full range at only 7 or 8 on the dial. There will always be -subtle
differences between the voices. If not excessive, these non-uniformities help "warm"
the Prophet's sound.
To help identify an errant voice, you may be able to use the fact that following TUNE,
the voices are initially assigned in order, 1 through 6. After these initial assignments it
is difficult to predict the voice assignment. After functional testing, when the cabinet
is opened, it will be easy to probe around PCB 4 to find the bad voice. Actually the
easiest way to identify the voice is to simply touch the ICs with your finger, while
holding the key to which the bad voice is assigned.
Note that since the Prophet always presets to program 00 on power up, it will be
necessary to switch PRESET off each time manual control is desired.
All tests begin with controls positoned as shown in Figure 1-1. The essential features
of this patch are that no oscillator waveforms are switched on, the filter and amplifier
are fully "open," and there is no modulation.
1-6
TM600A 7/83