Check/Adjust Attenuator Compensa ­ Tion; Check/Adjust Vertical Gain - Tektronix 221 Instruction Manual

Calibration — 221 Service
13. Check/Adjust Attenuation Compensation
a. Set the VOLTS/DIV switch to .2 and, set the
SEC/DIV switch to .1 m. See Fig. 5-6 for location of atten ­
uator adjustments.
b. Adjust the output of the square-wave generator for a
display of 4 divisions in amplitude.
c. Check for a square wave that is flat (flat top).
d. Adjust C122 for a square wave that is flat (flat top).
e. Set the square-wave generator for 50 kHz.
f. Set the SEC/DIV switch to 10 µs.
g. Check for a square wave that is flat.
h. Adjust C120 for a square wave that is flat.
i. Set the VOLTS/DIV switch to 2.
j. Set the SEC/DIV switch to .1 m.
k. Set the square-wave generator to 5 kHz and adjust
the output for a four-division display.
l. Check display for a flat square wave.
m. Adjust C125 for a flat square wave.
n. Set the square-wave generator for a 50-kHz signal.
o. Set the SEC/DIV switch to 10 µs.
p. Check the display for a flat square wave.
q. Adjust C1 23 for a flat square wave.
r. Set the VOLTS/DIV switch to 20 and remove the
50 ohm termination.
s. Set the output of the square-wave generator for a
five kHz, four-division signal.
t. Set the SEC/DIV switch to .1 m.
Fig. 5-6. Location of attenuator compensation and Vertical Gain
adjustments.
5-8
Vert Gain
R417
1573-16
u. Check for a flat square wave.
v. Adjust C1 28 for a flat square wave.
w. Set the square-wave generator for a 50-kHz signal.
x. Set the SEC/DIV switch to 10 µs.
y. Check for a flat square wave.
z. Adjust C126 for a square wave that is flat.

14. Check/Adjust Vertical Gain

a. Set the VOLTS/DIV switch to 50 m.
b. Set the SEC/DIV switch to .2 m.
c. Set INPUT COUPLING to DC.
d. Connect the standard amplitude calibrator to the 221
oscilloscope. Use a probe tip to BNC adapter.
e. Set the standard amplitude calibrator for a 0.2 volt
signal.
f Check for a display of four divisions.
g. Adjust R417 for a display of four divisions within
2%. See Fig. 5-6.
h. Check all the VOLTS/DIV switch settings (see
Table 5-2).
Table 5-2
Standard Amplitude
VOLTS/DIV
Calibration Setting
Setting
20 m Volts
5 m
50 m Volts
10 m
.1 Volt
20 m
.2 Volt
50 m
.1 .5 Volt
.2 1 Volt
2 Volts
.5
5 Volts
1
10 Volts
2
20 Volts
5
50 Volts
10
100 Volts
20
100 Volts
50
100 Volts
100
Number of
Divisions
4
5
5
4
5
5
4
5
5
4
5
5
2
1
REV. D, SEPT. 1977