HP 8568B, Performance Tests And Adjustments Manual, Page: 155 / 313

2. High-Voltage Adjustment (SN and Above)
H I G H
V O L T A G E
R E G U L A T O R
Figure 3-13. Location of High Voltage Adjustments
4. Set the LINE switch to ON. Set the front-panel INTENSITY
control fully counterclockwise (CRT beam at cut-off) to prevent
possible damage to the CRT.
5. Note the DVM indication at
DVM Indication:
6. Connect
the
high-voltage probe to the DVM, and connect the
probe to
7. Note the DVM indication.
DVM Indication:
8. Divide the DVM indication in step 7 by the DVM indication in
step 5. This gives the calibration factor needed to compensate for
high-voltage probe error.
Calibration Factor:
9. Disconnect the high-voltage probe from Set the
LINE switch to STANDBY. Remove the ac line cord from both
instrument sections.
Warning
The MAINS power-on indicator (red LED) should
be completely off before proceeding with this procedure. See
Figure 3-13 The indicator will remain lit for several seconds after
the ac line cord has been removed, and will go out slowly (the
light becomes dimmer until it is completely out).
Warning
With the protective cover removed in the following step, do not
place hands near the High-Voltage assembly. High voltage
(approximately -2400 V dc) can present even when the ac line
cord is disconnected.
10. Wait at least one minute for capacitors to discharge to a safe
level.
Adjustments