Adjustement and Tuning.

Before making any adjustements, allow for a 30 minutes warmup period.
All references to keys implies that C0 is 0v for a 1 volt/octave CV source.

Make sure JP10 has a jumper on the Analog Board (Step 112).

Make sure JP19 has a jumper on the Control Board (Step 3).

1. Voltages adjustements.

1.1 Main voltage

  • Connect DC voltmeter to test point TP1 and TPGND. Adjust -10V trimpot (R54) for -10.00v
  • Connect DC voltmeter to test point TP2 and TPGND. Adjust +10V trimpot (R114) for +10.00v

1.2 Oscillator 1 voltage

  • Connect DC voltmeter to test point TP3 and TPGND. Adjust -10V trimpot (R375) for -10.00v
  • Connect DC voltmeter to test point TP4 and TPGND. Adjust +10V trimpot (R119) for +10.00v

1.3 Oscillator 2 voltage

  • Connect DC voltmeter to test point TP5 and TPGND. Adjust -10V trimpot (R373) for -10.00v
  • Connect DC voltmeter to test point TP6 and TPGND. Adjust +10V trimpot (R374) for +10.00v

1.4 Oscillator 3 voltage

  • Connect DC voltmeter to test point TP7 and TPGND. Adjust -10V trimpot (R376) for -10.00v
  • Connect DC voltmeter to test point TP8 and TPGND. Adjust +10V trimpot (R377) for +10.00v

1.5 Envelops voltage

  • Connect DC voltmeter to test point TP9 and TPGND. Adjust +9.3V trimpot (R387) for +9.3v

1.6 Analog Board voltage check points

2. Tuning oscillators.

  • Connect a 1 volt per octave CV/Gate keyboard to the Cv and Gate input jack.
  • Connect a frequency counter to the High Main output jack.
  • Set Tune control to 0.
  • Set Glide Control to 0.
  • Set Noise Level control to 0.
  • Ascertain that all modulation switches are 'off'.
  • Set all range switches to 2'.
  • Set oscillator 2 & 3 Frequency controls to mid-position ('centered').
  • Set all waveform switches to 'sawtooth'.

2.1 Oscillator 1 tuning

  1. Set oscillator 1 Level control to 10.
  2. Set oscillator 2 & 3 Level control to 0.
  3. While holding A2 key, adjust oscillator 1 Range trimpot (R64) for 1760Hz.
  4. While holding A0 key, adjust oscillator 1 Scale trimpot (R66) for 440Hz.
  5. Repeat steps 3 and 4 until no further improvement is attainable.

2.2 Oscillator 2 tuning

  1. Set oscillator 2 Level control to 10.
  2. Set oscillator 1 & 3 Level control to 0.
  3. While holding A2 key, adjust oscillator 2 Range trimpot (R131) for 1760Hz.
  4. While holding A0 key, adjust oscillator 2 Scale trimpot (R133) for 440Hz.
  5. Repeat steps 3 and 4 until no further improvement is attainable.

2.3 Oscillator 3 tuning

  1. Make sure toggle switch "OSC3 CRTL" is in "OSC3 CRTL/Upper" position
  2. Set oscillator 3 Level control to 10.
  3. Set oscillator 1 & 2 Level control to 0.
  4. While holding A2 key, adjust oscillator 3 Range trimpot (R201) for 1760Hz.
  5. While holding A0 key, adjust oscillator 3 Scale trimpot (R197) for 440Hz.
  6. Repeat steps 3 and 4 until no further improvement is attainable.

2.4 Octave range adjustement

  1. Set oscillator 1 Level control to 10.
  2. Set oscillator 2 & 3 Level control to 0.
  3. Depress A2 key.
  4. Set oscillator 1 Range control to 2' : 1760Hz.
  5. Set oscillator 1 Range control to 32'. Adjust Octave trimpot R7 for 110Hz.
  6. Repeat steps 3 and 4 until no further improvement is attainable.

3. Audio Voltage Control Amplifier adjustements.

  1. Monitor the High Main output jack.
  2. Set oscillator 1, 2 & 3 Level control to 0.
  3. Connect a wire from TP12 and one of oscillator 1 outputs (JP11).
  4. Adjust trimpot VCA-2 (R263) for the minimum audio signal.
  5. Depress and hold a key.
  6. Adjust trimpot VCA-1 (R262) for the minimum audio signal.
  7. Remove wire from TP12 and JP11.

4. Filter adjustements.

4.1 Emphasis adjustement

  1. Set oscillator 1, 2 & 3 Level control to 0.
  2. Monitor the High Main output jack.
  3. Set filter Cutoff frequency to -1.
  4. Set filter Emphasis control to 0.
  5. Depress and hold a key.
  6. Emphasis should start when Emphasis contol is between 7 and 8. If not continue to step 7.
  7. Set Emphasis contol to 7.5.
  8. Adjust trimpot REGEN (R389) until regeneration starts.

4.2 Range adjustement.

  1. Connect a frequency counter to the High Main output jack.
  2. Turn toggle switches KB1/2 and KB2/2 off.
  3. Set Cutoff Frequency control at -1.
  4. Set filter Emphasis control at 10.
  5. Adjust trimpot Range (R390) for 440Hz.

4.3 Scale adjustement.

  1. Connect a frequency counter to the High Main output jack.
  2. Set Cutoff Frequency control at -1.
  3. Set filter Emphasis control at 10.
  4. Set amount of contour at 0.
  5. Turn toggle switches KB1/2 and KB2/2 on.
  6. Depress and hold A2.
  7. Adjust Cutoff Frequency control for 1760Hz.
  8. Depress and hold A0.
  9. Adjust trimpot Scale (R391) for 440Hz.
  10. Repeat steps 5, 6, 7 and 8 until the filter tracks 3 octaves.

5. Modulation mix Voltage Control Amplifier adjustements.

  1. Set oscillator 3 waveform switch to Triangle.
  2. Turn Mod-Mix full clockwise - This set oscillator 3 as modulation source.
  3. Set Mod-LEVEL control to 10 - This fully 'open' the VCA.
  4. Connect oscilloscope channel 1 to TP10 - VCA input. You should observe oscillator 3 waveform.
  5. Connect oscilloscope channel 2 to TP11 - VCA output.
  6. Adjust Offset trimpot (R384) to null any offset.
  7. Adjust Balance trimpot (R367) so that signal on oscilloscope channel 1 et 2 are identicals. (If necessary, adujst Initial lvl control (R368) to reduce gain)
  8. Set Mod-LEVEL control to 0.
  9. Adjust Initial lvl control (R368) for a 0v output on oscilloscope channel 2.
  10. Depress and hold a key.
  11. While switching OSC-MOD control on and off, adjust Offset trimpot (R384) for no pitch change.