Calibration—221 Service
DISPLAY
Equipment Required
2. Three-inch screwdriver
1. Time mark generator
3. Adapter (probe tip to BNC)
Control Settings
Preset the controls as given in the Preliminary Control
Setting. See Fig. 5-3 and Fig. 5-4 for locations of adjust
ment controls.
6. Check/Adjust Astigmatism and FOCUS
a. Set the SEC/DIV switch to the 1 V position (x-y
mode)
b. Set the INTENSITY control fo r a small spot, near
center o f screen.
c. Check that the spot is round.
d. Adjust the FOCUS side panel screwdriver adjustment
and the Astig. adjustment for a round spot.
7. Check/Adjust Trace Rotation
a. Set the SEC/DIV switch to 1 m.
b. Position the trace to the graticule center line.
c. Check that the trace is parallel to the center
horizontal line.
d. Adjust Trace Rotation R751 (screwdriver adjustment
on sidepanel) fo r a trace that is parallel w ith the horizontal
graticule lines. See Fig. 5-4.
Astig Adjust
Rear View
R752
r
Fig. 5-3. Location of Astigmatism and CR T Unblanking adjust
ments.
8. Check/Adjust CRT Unblanking
a. Set the INTENSITY to maximum, and set the
SEC/DIV switch to 1 /i.
b. Adjust unblanking adjustment R753 (see Fig. 5-3)
so that retrace is just blanked out.
9. Check Geometry
a. Preset the instrument controls as given in Preliminary
Control Setting.
b. Set the SEC/DIV switch to the 1 millisecond position,
and INPUT COUPLING to DC.
c. Connect the time mark generator to the probe by an
adapter (probe to BNC). Set the markers fo r 1 millisecond.
d. Set the VO LTS /D IV switch setting fo r a full-screen
deflection.
e. Check that vertical and horizontal bowing is less than
0.1 division.
Step Atten Bal
Probe Comp
R135
C l 12
Fig. 5-4. Location of Step Attenuator Bal, Probe Compensation,
and Focus adjustments.
5-6
REV C, MAY 1978
http://manoman.sqhill.com
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