HP 8568B, Performance Tests And Adjustments Manual, Page: 151 / 313

2. High-Voltage Adjustment (SN and Below)
and assemblies function properly and do not require
compensation, proceed directly to adjustment procedure 4, “Final
Display Adjustments (SN
and Below)“.
Discharge Procedure
The adjustment procedures in this manual do not require the removal
for High Voltage and
or discharge of the High-Voltage Regulator or CRT assemblies.
CRT However, if for any reason the High Voltage Regulator Assembly
or the post-accelerator cable must be removed, the following
procedure ensures the proper safety.
Warning
This procedure should be performed by qualified personnel only.
Voltages are present which, if contacted, could cause serious
personal injury. Approximately -4000 V dc is present on the
High-Voltage Regulator assembly even when the ac line
cord is disconnected. The CRT can hold a + 18 dc charge
for several days if the post-accelerator cable is improperly
disconnected.
Warning
Do not handle the High-Voltage Regulator Assembly or
High-Voltage Multiplier until the following high-voltage
discharge procedure has been performed.
1. Set the spectrum analyzer’s LINE switch to STANDBY, remove the
ac line cords, and remove the High Voltage Regulator safety
cover.
Warning
With the ac power cord disconnected, voltages are still present
which, if contacted, could cause serious personal injury.
Warning
In the following step, a large arc of high voltage should be drawn.
Be careful.
2. Locate the snap connector on the CRT post-accelerator cable.
It is shown in Figure 3-11 as item 1. Using a long flat-bladed
screwdriver with an insulated handle, carefully pry the connector
loose but do not disconnect the cable.
a. Using one hand, remove the end of the cable labeled item 2
in Figure As the end of the cable becomes free, touch
the end of the cable to the CRT’s metal cover. A large arc of
high voltage should ground to the CRT cover. The CRT is not
discharged yet!
b. Reconnect the CRT post-accelerator cable, and repeat the above
step until high-voltage arcs no longer appear.
3. Leave the CRT post-accelerator cable disconnected, and remove
the cover
on
the High Voltage Regulator.
4. Connect a jumper wire (insulated wire and two alligator clips)
between the shaft of a small screwdriver and the chassis ground
lug on the inside of the high-voltage shield.
Adjustments 3-37