CONTROL POSITION
Frequency As required by procedure
Amplitude 1.00 V
Offset 0.00 V
Sweep Stop 2.0 MHz
Sweep Time 1 S
Sweep Marker 10 MHz
Operating Mode Normal (all lights off)
Trigger Mode Continuous (all lights off)
Output Squarewave
7-3. ADJUSTMENT PROCEDURE
7-3-1. Power Supply Adjustment
Equipment: DMM
1. Set DMM to DC measurements. Measure and record the
-15 V supply voltage with 10 mV resolution.
2. Adjust R4 so that the +15 V supply would be the same as
the voltage level recorded in step 1.
7-3-2. Distortion Adjustment
Equipment: Distortion Analyzer, Oscilloscope
1. Change 8020 Output setting to Sine.
2. Change 8020 Frequency setting to 2.000 KHz.
3. Set the oscilloscope to 1V/Div. and DC coupling and adjust
the trace line vertically to be exactly at the center of the screen
(0 V).
4. Connect the OUTPUT terminal to the oscilloscope and ad-
just R172 to get a symmetrical waveform, about the 0V line,
on the screen.
5. Disconnect the OUTPUT from the oscilloscope and con-
nect the OUTPUT to the distortion analyzer.
6. Adjust R115 and R129, repeatedly, until the distortion
reading on the analyzer is less than 0.2%. Note that each one
of these resistors contribute a small amount to the distortion
correction. It is up to the service technician to find the most
effective sequence to perform this step.
7. Disconnect the OUTPUT from the analyzer and repeat
steps 3 and 4.
7-3-3. Frequency Adjustment
Equipment: Counter, Oscilloscope, 50 ohms feedthrough
termination
1. Change 8020 operating mode setting to VCO.
2. Change 8020 Frequency setting to 1.990 KHz.
3. Connect the OUTPUT terminal to the universal counter
input. Terminate counter input with 50 ohms feedthrough
termination.
4. Set counter to frequency measurements and adjust R29 for
a reading of 1.990 KHz +/-10 Hz on the counter display.
5. Change 8020 Frequency setting to 19.90 KHz and check
that the reading on the counter is 19.90 KHz +/-30 Hz. If read -
ing is not within the specified value readjust R29 so that the
error in 1.990 KHz and 19.90 KHz is the same.
6. Change 8020 Frequency setting to 2.00 MHz.
7. Set counter and adjust C38 to give a reading of 2.00 MHz
+/-30 KHz on the counter display.
8. Set the oscilloscope to 20 mV/Div. and DC coupling and
adjust the vertical trace line to be exactly at the center of the
screen (0 V). Connect a 10:1 high frequency probe,with a
very short ground lead, to the junction to TP7. Adjust the ver-
tical gain of the oscilloscope so that the peak to peak ampli-
tude on the screen will be exactly 6 divisions. Change 8020
frequency setting to 15.00 MHz. Select C56 and adjust C60
until peak to peak trace is 6 divisions +/-1 small division.
Note that the trace should be vertically symmetrical about the
0 V line.
9. Readjust C60 to give a reading of 15.00 MHz +/-300 KHz
on the counter display.
10. Change 8020 Frequency setting to 2.00 MHz.
11. Check with counter if reading is 2.00 MHz +/-30 KHz. If
reading is not within the specified value readjust C38.
12. Repeat steps 9 through 11 until best accuracy is achieved.
13. Change 8020 Frequency setting to 199.0 KHz.
14. Set counter and select C44 (approximately 330PF) to give
a reading of 199.0 KHz +/-3 KHz on the counter display.
15. change 8020 Frequency setting to 1.990 MHz.
16. Select C41 (approximately 47PF) to give a reading of 1.990
MHz +/-30 KHz on the counter display.
7-3-4. Low Frequency Adjustment
Equipment: Counter
1. Change 8020 Frequency setting to 10.00 Hz.
2. Connect the 8020 OUTPUT terminal to the counter.
3. Adjust R59 to 10.00 Hz +/-.1 Hz.
7-3-5. Low Frequency Distortion Adjustment
Equipment: Distortion analyzer, Counter
1. Change 8020 Frequency setting to 10.00 Hz.
2. Change 8020 Output setting to sine.
3. Connect 8020 OUTPUT terminal to the distortion analyzer
input.
4. Adjust R44 for minimum distortion.
Adjustments Model 8020
Page 7-2
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