HP (Hewlett-Packard) HP 8568B TV Converter Box User Manual


 
2. High-Voltage Adjustment (SN 3004A and Above)
11. Remove the protective cover from the
AlA
High-Voltage
Regulator Assembly. A label should be visible on the
AlA3Al
High Voltage Assembly.
(AlASAl
is mounted on the
non-component side of the High-Voltage Regulator Assembly as
shown in Figure 3-14.) Record the voltage listed on the label for
use in step 15. In cases where more than one voltage is listed on
this label, record the value which is closest to -2400 Vdc.
V dc
Warning
With power supplied to the instrument,
AlA3TP2A
is at a voltage
level of approximately -2400 V dc. Be extremely careful.
12. Connect the high-voltage probe to AlA3TP2A. See Figure 3-14 for
the location of the test point.
AlA3Al
LABEL
AlA3TPZP
AlA3TP2A
Figure 3-14. Location of
AlA
Label and Test Point
13. Reconnect ac line cords to both instrument sections. Set the LINE
switch to ON.
14. Wait approximately 30 seconds for the
de
regulator circuits to
stabilize.
15. Adjust AlA6R103 HV ADJ for a DVM indication equal to the
calibration factor (calculated in step 8) times the voltage labeled
on the top of the
AlA3Al
High-Voltage Assembly (noted in step
11). See Figure 3-13 for the location of the adjustment.
V dc
EXAMPLE:
If the calibration factor calculated in step 8 is 0.00099, and
AlASAl
is labeled for -2400 V, then adjust AlA6R103 HV ADJ
for a DVM indication of:
0.00099 x (-2400 V) = -2.376 V dc
3-42 Adjustments