HP 3456A Operating And Service Manual page 113

Model 3456A
'' c
"
R,I.
•
A40C3 0 1 60·2202
A40C 1 1 0 1 60·3502 3
A40C 1 2 0 1 60·4807 5
0 1 6 0·0302
A40C22 5
A40R21 0698·4470 5
A40R24 0757,0279 0
A40R60 0757·3486 2
7·17. Chang. #6
7-18. For serial numbers 2015A0216O and below.
a. Page 8-65/8-66, Figure 8-61 (Schematic I , Input
Switching Schematic). Change A20CI I I from l00pF to
150pF. Do not change the capacitor if UI06 has been
replaced by an op amp with part number 1820-0478.
b . Page 6-8/6-12, Table 6-4 (Replaceable Parts).
When replacing A20U 106, replace with the part number
( 1 820-0478) shown in Table 6-4. The old part number is
1820-0477. If UI06 has been replaced, replace C I I I
with the part number (0160-3336) shown i n Table 6-4.
The old part number is 0160-4814.
c. Page 6-8, Table 6-4 (Replaceable Parts). When
replacing A20C70I, replace with the part number
(01 80-0269) shown in Table 6-4. The old part number is
01 80-0230.
7·'9. Ch.nga #7
7-20. For serial numbers between 2015A01866 and
20ISA0290S.
a. Page 8-79/8-80, Figure 8-68 (Schematic 7, AC
Converter Schematic. Change A40R21 from 6.98K ohm
to 9.09K ohm.
b. Page 6-16, Table 6-4 (Replaceable Parts). Change
A40R21 to 9.09K ohms (Part Number 0757-0288). If the
Oae·lfllion
CAPACITOR·FXO 75pF 300V
CAPACITOR·FXO .3pF 500VOC
CAPACITOR·FXO 33pF 300VOC
CAPACITOR·FXO .01S"F 200VDC
RESISTOR 6.98K 1 % . 1 2 S W
RESISTOR 3 . 1 6 K 1 % .1 2SW
RESISTOR 301 1 % .125W
f1' J"
Figure 7·5. Change #8 on Schematic 7
resistor is to be replaced, use the value and part number
shown in Table 6-4 (6.98K ohms, Part Number
0689-4470).
7·21. Chang. #8
7-22. For serial numbers 201 5A02970 and below.
a. Page 8-79/8-80, Figure 8-68 (Schematic 7, AC
Converter Schematic). Change the Input Atlenuator
Circuitry of the AC Converter as shown in Figure 7-5.
Note that in the change, the value of R3 is 5 1 ohms in­
stead of I K ohms.
b . Page 6-15, Table 6-4 (Replaceable Parts). Change
the following:
A,t. P,n
On.. Ih.,bt,
A40R3 0683·S10S
7·23. Chang. #9
7-24. For serial numbers 2015A03070 and below. The
following is a ROM change and requires some changes
of the signatures listed in Service Group A of the
manual. I f a ROM (A4V5, V7, or V8) is to be replaced
in the 3456A because of a failure, make sure the new
ROMs used as replacements are the ones listed in Table
6-4 (Pan Number of U5 is 1 8 1 8-1 629, V7 is 1818-1630,
and U8 is 1818-1631). In addition, all ROMs (U5, U7,
and U8) need to be replaced, even though only one
ROM may be defective. If the ROMs presently in the in­
strument are the new ROMs, then only the defective
ROM need to be replaced. The old ROMs listed in step a
(which follows this paragraph), are no longer available.
Backdating
C
0
Daeription
4 RESISTOR 51 5% .25W
:
I 5�
Rev B 7-5