Tektronix DCM300, Техническое описание

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TAS 200 Series Adjustment Procedures
30
Handheld and Benchtop Instruments Basic Service
Use the following procedure to adjust the DC balance.
1. Set up the oscilloscope as follows:
VERTICAL MODE CH1 (CH2)
CH 1 (CH 2) VERTICAL VARIABLE CAL
CH 1 (CH 2) GND
In
2. On the oscilloscope Main board, adjust VR101 (VR201) for a minimal trace
shift when switching the front panel CH 1 (CH 2) VOLTS/DIV control
between 5 mV and 10 mV. See Figure 10 for the adjustment locations.
3. Verify that the trace shift is less than
±
0.5 divisions for each CH 1 (CH 2)
VOLTS/DIV step between 5 mV and 5 V.
4. On the Main board, adjust VR104 (VR204) for minimal trace shift when
switching the CH 1 (CH 2) VOLTS/DIV control between 2 mV and 10 mV.
See Figure 8 for the adjustment locations.
5. Verify that the trace shift is less than two divisions when switching the
VOLTS/DIV control between 1 mV and 2 mV.
6. Set the VERTICAL MODE to CH2 and repeat steps 2 through 5 for CH 2.
Use the following procedure to adjust the variable DC balance.
1. Set up the oscilloscope as follows:
VERTICAL MODE CH1 (CH2)
CH 1 (CH 2) VOLTS/DIV 10 mV
CH 1 (CH 2) VARIABLE CAL
CH 1 (CH 2) GND In
2. On the Main board, adjust VR106 (VR206) for a minimal trace shift while
rotating the front panel CH 1 (CH 2) VARIABLE control between the
fully clockwise and the fully counterclockwise positions. See Figure 8 for
the adjustment locations.
3. Set the VERTICAL MODE to CH2 and repeat step 2 for CH 2.
Use the following procedure to adjust the channel 2 inverted balance and
position center.
1. Set up the oscilloscope as follows:
VERTICAL MODE CH2
CH 2 GND In
2. Position the trace on the center horizontal graticule line using the CH 2
VERTICAL POSITION control.
DC Balance
Variable DC Balance
Channel 2 Inverted
Balance and Position
Center