HP 3456A Operating And Service Manual page 112

Backdating
7·15. Changa #5
7-16. For serial numbers 2015AOl 865 and below. All
changes pertain to the A40 Assembly.
a. Page 8-79/8-80, Figure 8-68 (Schematic 7, AC
Converter Schematic). Do the following:
I . Add C I I (a 0.3pF capacitor) to the schematic,
as shown in Figure 7-4. Do not add the capacitor if
missing from the A40 assembly or hybrid U3 has
been replaced.
2. Change C3 from 62pF to 75pF. Do not change
the capacitor if C I l is missing from the A40
assembly or hybrid U3 has been replaced.
3 . Change C22 from .01 5�F to .018p.F. Do not
change the capacitor if C 1 I is missing from the
A40 assembly or hybrid U3 has been replaced.
..
"
Rev B
7-4
b. Page 6-14/6-1516-16, Table 6-4 (Replaceable
Parts). Do not make the following changes or additions
i f capacitor Cl I is missing from the A40 assembly or
hybrid U3 has been replaced .
m
�3pf
g: , , " :,.J
�/o U�
no
n,
.
:
. :
'
"
.
,,
�/O Ul
Figure 7·4. ChanllB #5 on Schematic 7
4. Change R21 from 9.09K ohms to 6.98K ohms.
Do not change the resistor if Cl I is missing from
the A40 assembly or hybrid U3 has been replaced.
5. Change R24 from 4.99K ohms to 3.16K ohms.
Do not change the resistor if C I I is missing from
the A40 assembly or hybrid U3 has been replaced.
6. Change R60 from 232 ohms to 301 ohms. Do
not change the resistor if C I I is missing from the
A40 assembly or hybrid U3 has been replaced.
Model 3456A
.
.
)