Korg DSS-1 - TG Board A;D Check; Test Procedures (VCF;Resonance)

11. CHECK AND ADJUSTMENT PROCEDURE
■CAUTION
1. This product has been throughly adjusted at the fac
tory before shipment. Therefore never turn any Semi-
Fixed VRs other than those required for repair. When
adjust Semi Fixed VRs, please refer to Semi-Fixed
VR Location Diagram.
2. After turning on Power, wait at least 15 minutes
before beginning test and adjustment.
Necessary equipments for the procedure are as
follows.
© Oscilloscope ® Digital Volt Meter (DVM) (3) Fre
quency Counter ® Noise Meter
• Power Supply Voltage Check and Adjustment
(KLM-786)
1. Connect a Digital Voltmeter (DVM) to Connector CN4
1 pin (red wire) of KLM-786. (GND to GND on the
board)
2. Confirm if the DVM value is within +5V ±0.2V
3. Adjust VR1 if necessary.
Note:
As other Power Supplies ±5V, ± 12V are produced
by three terminal regulators, adjustment is not
necessary.
Deviation of the regulator is less than 20%.
• DAC Power Supply Check and Adjustment
(KLM-781)
1. Connect a DVM to IC18 1 pin of CPU2 board
KLM-781. (GND to GND of the board)
2. Confirm if the DVM value is within + 5V±0.2V.
3. Adjust VR1 if necessary.
• TG Board A/D Check and Adjustment (KLM-782)
1. Connect an oscilloscope (DC, 2V/div, 5/xsec/div) to
TP3. (GND to TP4)
Note:
Probe is 10 : 1.
2. Press Sample Key. LED is lit and Display shows as
Fig. 1.
Fig. 1
SAMPLE MODE
*•*
SELECT S.Frq = 32KHZ
3. Press Enter Key
Fig. 2
SELECT TOTAL TIME
4.0 or 8.0 (sec)
4. Press Enter Key
Fig. 3
F1 SMPL-NO. MEN DIV
01 01
5. Press No. 2 Key
Fig. 4
ATTN=00dB GAIN-OOdB
6. Confirm waveform of Fig. 5.
7. Adjust VR 1 if necessary.
Fig. 5
Fig. 6
Fig. 7
GOOD
Not synchronized with trig
ger of the oscilloscope.
NO GOOD
Synchronized with trigger of
the oscilloscope. Pulsewave-
form from "H" to "L" is
observed.
NO GOOD
Synchronized with trigger of
the oscilloscope. Pulsewave-
form from ML" to "H" is
observed.
Note:
Though it may be difficult, you can get it by ad
justing TIME/div value of the oscilloscope within
20sec. ~ 2/tsec.
43
Scan by Manual Manor
http://www.markglinsky.com/ManualManor.html