Figure 14: The Position Of The Attenuation Compensation Capacitance - Owon SDS Series Service Manual

2.
Calibrate the attenuation compensation capacitance of the CH1:
Set the Vertical scale of CH1 to 10V; adjust the C25 adjustable capacitance until the
Correctly Compensated waveform is achieved. Set the Vertical scale of CH1 to 20V; adjust
the C24 adjustable capacitance until the Correctly Compensated waveform is achieved.
Figure 14 indicates the position of the adjustable capacitance on the main board.
C25

Figure 14: The position of the attenuation compensation capacitance

3.
Calibrate the probe in the CH2:
Replace the CH1 with CH2 in the step 1, redo it.
4.
Calibrate the attenuation compensation capacitance of the CH2:
Set the Vertical scale of CH2 to 10V; adjust the C23 adjustable capacitance until the
Correctly Compensated waveform is achieved. Set the Vertical scale of CH2 to 20V; adjust
the C22 adjustable capacitance until the Correctly Compensated waveform is achieved.
Figure 14 indicates the position of the adjustable capacitance on the main board.
5.
Calibrate the attenuation compensation resistance of the CH1:
Input an external 6V/1KHz sine signal to CH1, observe the actual value of Vpp. Then change
the frequency of the external signal to 10Hz, observe the actual value of Vpp. If it is different
from the previous one, adjust the R66 adjustable resistance to make it equal the previous one.
Figure 15 indicates the position of the adjustable resistance on the main board.
6.
Calibrate the attenuation compensation resistance of the CH2:
Input an external 6V/1KHz sine signal to CH2, observe the actual value of Vpp. Then change
the frequency of the external signal to 10Hz, observe the actual value of Vpp. If it is different
from the previous one, adjust the R66 adjustable resistance to make it equal the previous one.
Figure 15 indicates the position of the adjustable resistance on the main board.
Section 4: Debugging and Calibration
C22
C24
20
C23