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2. High-Voltage Adjustment (SN 3001A and Below)
39. Slowly adjust the front-panel INTENSITY control through its
entire range while monitoring the peak-to-peak voltage at
AlA3TP5.
As the INTENSITY control is turned clockwise, the
peak-to-peak voltage at
AlA3TP5
will drop. To prevent long-term
CRT damage, this voltage should not drop below (V,,
-
5O)V,.,
or
12
VP-,,,
whichever is greater. See Figure 3-10. (The value of
V,,
was recorded in step 34.)
If the front-panel INTENSITY control cannot be set fully
clockwise without dropping below this minimum peak-to-peak
voltage, then perform the following:
a. Set the INTENSITY control fully counter clockwise.
b. Set the LINE switch to STANDBY.
c. Increase the value of AlA2R9.
d. Return to step 34.
Note
Maximum CRT life expectancy is obtained when the peak-to-peak
voltage at
AlA3TP5
is as large as possible with the INTENSITY
control set fully clockwise. The display illumination must fully
disappear with the INTENSITY control set fully counter clockwise.
50.0
uS/dlv
1
f
85.00 v
Figure 3-10. Waveform at
AlA3TP5
40. Replace the cover on the
AlA
High-Voltage Regulator Assembly.
41. The High-Voltage Adjustment is completed. If an
AlA2,
AlA4,
or
AlA
assembly has been repaired or replaced, perform
adjustment procedure 3, “Preliminary Display Adjustment (SN
3001A
and Below)“, and then adjustment procedure 4, “Final
Display Adjustments (SN
3001A
and Below)“. If the
AlA2,
3-36 Adjustments