Korg Poly-800II Service Manual page 28

14. Master oscillator check and adjustment (KLM-1032)|
Set tune knob to center and bend intensity to maximum. Con
nect AT-12 to line out jack.
1) Select program no. 12.
2) Play C3 key and set to HOLD.
3) Confirm AT-12 indication of — 1 OCT. C, 0 cent. If
necessary, abjust coil KL-O03.
4) Next, move joystick to maximum upward pitch bend position
and confirm AT-12 reading of — 1 OCT, G, +35 cents. Ad
just KLM-601 VR2 if necessary.
5) At maximum joystick downward pitch bend, AT-12 indica
tion should be -2 OCT. -35 cents. Adjust KLM-601 VR1 if
necessary.
• VR3 is a semi-fixed resistor to fix range of tune VR on front
panel.
Confirm +40 - + 70 cents when tune VR is at # max posi
tion.
• Confirm -40 - -70 cents when tune VR is at b max posi
tion.
If necessary, Adjust VR3.
15. Cutoff check and adjustment (KLM-10327
1) Select program no. 13.
2) Play C3 and set to HOLD.
3) Connect on oscilloscope to CN6A pin 3 and observe
waveform as in figure 1.
4) Adjust VR2 to obtain maximum waveform amplitude.
6. Resonance check and adjustment: (KUVM032) |
1) Select program no. 14.
2) Play C3 and set to HOLD.
3) Confirm to oscillation and confirm that waveform is as shown
in figure 2.
4) Abjust VR5 if necessary to prevent oscillation or to correct
waveform deviation from figure 2 example.
200-
600Vp-
17. S/H CLOCK check and adjustment
1. S/H CLOCK Verification, Adjustment
1) Connect a frequency counter to TEST POINT 3 (TP3).
2) Check that the frequency counter displays 20kHz ± 0.5kHz.
3) Abjust VR3 if necessary.
NOTE:
Waveforms on the oscilloscope are as follows; (Hg-1)
+ 4V
OV
50/isec
DC,2V/div, 10/zsec/div
Flo-1
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