Korg Trident MK1 User Manual

(3) Bias level check and adjustment
1) Set scale to 8', bowing to on, level to 10, tone to
10, and KBD filter balance to 10, then check the
following, playing eight or more notes together
in the lower part of the keyboard.
2) Vibrato bias
Connect oscilloscope to Q11 (2SC945) emitter
and check to see that the waveform is not distor¬
ted. Adjust VR-3 as necessary to eliminate
distortion.
3) Ensemble 1 bias
Check for waveform distortion with oscilloscope
connected to Q2 (2SC945) emitter. Adjust VR-1
if necessary to remove distortion.
4) For ensemble 2 and ensemble 3, check Q13 and
Q6 and adjust VR-4 and VR-2, respectively, in
the same way.
7. Signal Generator (KLM-301)
(1) Antilog amp adjustment
1) Measure anti log output with a digital multi¬
meter, connecting the GND side to -1IV and the
positive side to the exposed lead of R57 (47
ohms, connected to 1C 4558 no.2 pin).
2) Play C3 eight times and adjust total tune to ob¬
tain 6.00mV (±0.1 mV) antilog output. The total
tune knob should be within ±1 scale marking of
center.
3) Set VCO 1 scale to 4'.
1. Play C6 eight times and adjust VR-6 to obtain
4.800V (±0.003V).
2. Play C3 eight times and adjust VR-7 to obtain
600.0mV (±0.3mV).
3. Play Cl eight times and adjust VR-5 to obtain
150.00mV (±1 mV).
4. Repeat steps 1 through 3 as many times as neces¬
sary to meet tolerances.
(2) VCO 1 tuning
1) Set assign mode to 2 and test with tuner.
2) Start with unit 0.
1. Play C6 and adjust VR-2 to obtain a 0 cent (±1
cent) reading.
2. Play Cl and adjust VR-1 to obtain a 0 cent (±3
cent) reading.
3. Repeat steps 1 and 2 above as many times as
necessary to bring C2, C3, C4, and C5 with ±3
cents.
3) Repeat the above adjustments (1—3) for units
1-7.
(3) VCO 2 tuning
1) Set assign mode to 2 and test with tuner.
2) Set PW/PWM to 10 to eliminate the sound of
VCO 1. Set VCO 2 scale to 4' and tune in the
same was as for VCO 1.
(4) Stretch tuning
To be performed as follows after completing VCO 1
and VCO 2 tuning.
1) Play C6 and adjust VR-6 to obtain a +10 cent
(±2.5 cent) reading for units 0—7.
2) Play C3 and adjust VR-7 to obtain a 0 cent (±2.5
cent) reading for units 0—7.
3) Play Cl and adjust VR-5 to obtain a -7.5 cent
(±2.5 cent) reading for units 0—7.
4) Repeat steps 1 through 3 several times. It is not
necessary to check other keys.
8. Flanger (KLM-291)
(1) Clock frequency check
1) Set intensity to 0 and use a frequency counter to
measure the flanger's clock frequency (KLM-291
TP6 or 7).
2) Ascertain that frequency is 90—110kHz when
manual is at 0, and 0.9—1.1kHz when manual is
at 10. If not within tolerances, adjust V-3 (center
frequency) and V-4 (fluctuation range) as neces¬
sary.
(2) Mix level check
1) Set VCO 1 waveform to n_, apply flanger to
synthe, and check synthe out with an oscillo¬
scope (1 msec/cm, 0.1 V/cm).
2) Play C4, set flanger intensity to 0, and turn
manual from 0 to 10, confirming that the wave¬
form just about disappears at about 4 (3—5).
3) If you don't get the kind of pattern shown in the
above illustration and the n_ waveform still re¬
mains, turn manual, stopping at the point of
minimum amplitude, then adjust VR-2 to further
reduce amplitude to minimum.
(3) Feedback adjustment
1) Apply flanger to synthe, set both intensity and
manual to 0, and check synthe out.
2) Turn feedback from 0 to 10 and ascertain that
the flanger begins self-oscillation at or above 7 on
the knob scale (without playing a key).
3) Adjust VR-1 if self-oscillation occurs at the
wrong point.
21

Korg Trident MK1 Specifications

General

Brand	Korg
Model	Trident MK1
Category	Electronic Keyboard
Language	English