2 1. Frequency Response Adjustments
177.
If the Preselector DAC value difference recorded in step 176
is greater than f0.5, remove the
A6A12
YTX Driver Assembly
from the RF Section and determine the current values of
factory-select components
A6A12C1,
A6A12C2,
A6A12Cl1,
and
A6A12C23.
Then, refer to
Table
3-16 to determine the
final
capacitor values to install for
A6A12C1,
A6A12C2,
A6A12Cl1,
and
A6A12C23.
Find the line in the table that corresponds
to the current
values
of the four factory-select capacitors
(A6A12Cl
and
A6A12C2
are in parallel, and
A6A12Cll
and
A6A12C23
are in parallel). Add the difference recorded in step
176 to the line number corresponding to the current values to
determine the line number of the
final
capacitor
values
to install
for
A6A12C1,
A6A12C2,
A6A12Cl1,
and
A6A12C23.
See
‘Ihble
3-4 for HP part numbers. See Figure 3-90 for the locations of
A6A12C1,
A6A12C2,
A6A12Cl1,
and
A6A12C23.
For example, if the average Preselector DAC value for [AUTO)
SWEEP TIME is 35.4 and the average
value
for [SWEEP TIME)
1s
is 32.0, the difference recorded in step 177 is
+3.4.
Assume
that the currently installed
value
of
A6A12Cl
is 0.33
pF,
the
value of A6A12Cll is 0.22
PF,
and that
A6A12C2,
A6A12C3,
and
A6A12C23
are not installed. These values correspond to
line 0 of
‘lkble
3-16. The final capacitor values are listed in line
3, determined by adding the difference of +3.4 to line number
0. The value of
A6A12Cl
is correct already, and
A6A12Cll
is
changed to a 0.1
,QF
capacitor.
Line
-8
-7
-6
-5
-4
-3
-2
-1
0
+l
+2
+3
+4
+5
+6
+7
+8
T
‘lhble
3-16.
A6A12 YTX Driver Assembly Fhctory-Select
Capacitor Values
A6A12Cl A6A12C2
A6A12Cll
0.33 0.22
0.22
0.33
0.22
0.22
0.33 0.22
0.22
0.33
open
0.22
0.33
open
0.22
0.33
open
0.22
0.33
open
0.22
0.33
open
0.22
0.33
open
0.22
0.33
open
0.22
0.33
open
0.15
0.33
open
0.10
0.15
open
0.22
0.33
open
open
open
open
0.22
open
open
0.22
open
open
0.15
Capacitor
Value
5
(PI
A6A12C23
0.33
0.22
0.22
0.33
0.33
0.22
0.15
0.10
open
open
open
open
open
open
open
open
open
1
A6A12C3
open
open
open
open
open
open
open
open
open
open
open
open
open
open
open
open
open
Adjustments
3-203
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