Korg EX-8000 - Voice Circuit Adjustments

3. VGA Level Check and Adjustment (KLM-662)
Turn off power and then on pressing number keys f7] and
[8] and T«t Mode becomes 2.
Oscillating voice is displayed on LED Display with any
single key being played under this mode.
Note: It must be Test Mode 2 though voice displaying is
not required.
1) Select Program number 11.
2) Connect an Oscilloscope to [TP-SG] (GND side -
[TP-AG]) and observe amplitude of output waveform.
3) Press C5 key and observe waveform described in Fig. 1.
4) Adjust Semi Fixed VRs (VR101 - VR801) of oscillating
voice (refer to Voice Display) to obtain waveform of
amplitude being 0.7VP-P.
Remarks: Allowance of deviation of each voice is under
40mV.
4. OSC 2 Level Check and Adjustment (KLM-662)
1) Select Program number 12.
2) Make same adjustment as VCA Level one.
3) Necessary Semi Fixed VRs for adjustment are among
VR105 - VR805 of oscillating voice, (refer to Voice
Display)
5. VCF Resonance Check and Adjustment (KLM-662)
1. Level
1) Select Program number 13.
2) Connect an Oscilloscope to [TP-SG]. (GND side to
[TP-AG])
3) Press any single key and confirm amplitude of output
waveform of each voice is 0.9VP-P. Unless, adjust Semi
Fixed VRs among VR 103-VR803 of oscillating voice.
Remarks: Allowance of deviation of each voice is under
40mVP-P.
2. fo
1) Select Program number 13.
2) Connect Chromatic Tuner AT-12 to Output Jack of
EX-8000.
3) Press any single key and confirm oscillation frequency of
each voice on AT-12 Display is C (523Hz), 1 octave, 0 cent.
4) Unless, adjust Semi Fixed VRs among VR102 - VR802
of osctilating voice.
Remarks: Allowance of deviation of each voice is 0 cent ±
10 cent.
3. fc
1) Select Program number 14.
2) Connect Chromatic Tuner AT-12 to Output Jack of
EX-8000.
3) Press any single key and confirm oscillation frequency
of each voice on AT-12 Display is C (2093Hz), 3 octave, 0
6. Noise Level Check and Adjustment (KLM-662)
1) Select Program number 15.
2) Connect a Noise Meter to [TP-SG] (GND side - [TP-
AG] ).
3) Press any single key and confirm value of the meter is
-15dbm.
4) Unless, adjust VR1 to obtain correct value.
7. DWGS Clock Check and Adjustment (KLM-771)
1) Connect a Frequency Counter to [TP-CLK] (GND side
to[TP-DG]).
2) Confirm the counter value is in range of 6.395MHz -
6.405MHz.
3) Unless, adjust VR2 to obtain correct value.
8. Digital Delay MG-CLK Check and Adjustment
(KLM-775)
1) Select Program number 16.
2) Connect a Frequency Counter to [TP-CLK] (GND side
to [TP-AG]).
3) Confirm the counter value is 20.0kHz. (Effective with
3 figures only.)
4) Unless, adjust VR3 to correct value.
5) After 3) is confirmed, select Program number 17.
6) Confirm the counter value is in range of 36.0kHz -
43.0kHz.
9. Digital Delay Output Waveform Center Position Check
and Adjustment {KLM-775)
1) Select Program number 17.
2) Connect an Oscilloscope to [TP-EXP] (GND side to
[TP-AG]). Adjust lit line of the Oscilloscope to 0 volt
line of the screen.
3) Press C5 key and confirm center of amplitude of output
waveform is on 0 volt line of the sdreen.
4) Unless, adjust VR2 to obtain correct position.
10. Digital Delay Feed Back Check and Adjustment
(KLM-775)
1) Select Program number 18.
2) Press C5 key and confirm if delayed sound lasts 2
seconds without no ringing.
3) Unless, adjust VR1. (Start to ring when turn to the right.
Turn to the left and adjustment point is where ringing
stops.)
4) After 2) is confirmed, select Program number 21.
5) Press C5 key and confirm if there is no ringing with
delayed sound.
4) Unless, adjust Semi Fixed VRs among VR 104 - VR804
of oscillating voice.
Remarks: Allowance of deviation of each voice is under
Ocent± 10 cent. : .
| POLY-800 \
\ AT-12 |
MIDI OUT
MIDUN a
OUTPUT
EX-8000
OUTPUT I
1
-41-
Scan by Manual Manor
http://www.markglinsky.com/ManualManor.html