HP 3400A Operating And Service Manual page 59

Appendix C
CHANGE
#4 (Cont'd)
Model 3400A
CHANGE
#5
CHANGE
#6
Manual Backdating
Changes Model 3400A Page
2
Table 7-1 Replaceable
Parts:
Change R701 and R702
to
-hp- Part No. 0693-4731, 47
kft.
Delete
C711
(0160-0167), C712 (0180-0282),
R712
(0687-2241),
R713 (0686-2225),
Q706
(1854-0022),
and
CR718
(1902-0046).
Change
A7 Board Assembly
-
Power
Supply
to
-hp-
Part No. 03400-66505.
NOTE:
-hp- Part No.
03400-66507
is directly
interchangeable with
03400-66505.
Figure
C-l and Table C-l:
Change
capacitor C602
to
35 /iF (-hp-
Part No. 0180-0064).
Change
resistor
R630
to
100
kft
(-hp-
Part No. 0683-1045). Also, change
transistors
Q601
to
-hp- Part No. 1850-0060, Q602
and
Q603
to
-hp- Part
No. 1850-0062.
NOTE-
To
reduce
meter
jitter
replace
all of
the
above components with
components
listed in
Table 7-1.
It
is
also re-
commended
to
change resistor
R606
to
a
3300ft resistor described
in
Table
7-1.
Some
instruments
(Serial
Prefixed
714-)
may
have a
1
/iF capacitor for
C602
(Figure C-l).
If
C602
fails
or
if
low frequency
oscillations
(±5%) occur on
meter change C602
to 10 juF
described
in
Table 7-1.
Instruments with serial
number between 714-06226 and 714-07525 have a
4700ft
resistor for R606.
If
R606
fails
or
if
meter
jitter
occurs
replace
R606
with
3300ft resistor
described
in
Table 7-1.
NOTE
#1
NOTE-
CHANGE
#7
Some
instruments with serial
number
between 714-06526 and 714-06925
in-
clusive
have a
different
second
atten-
uator
assembly than
the
one described
in this
manual.
Check
the value of
resistor
R301 on
the
second attenuator
assembly.
If
resistor
R301
is 150ft
disregard
manual
changes described
below.
If
the
value
of
R301
is
other
than
150ft,
and
the Serial No. is
within
the
range
shown
above,
make
the follow-
ing
manual changes: (Change
#7)
Figure
6-1,
Second
Attenuator Schematic and Table
7-1,
Replaceable Parts:
Change
value
of
R301 thru
R311 as
follows:
R301
to 180ft
R302, R304, R306,
R308 and R310
to
410.27ft
R303,
R305 to 277.0ft
R307,
R309 to 277.7ft
R311 to 189.3ft
Add
the
following note
to
Schematic and Replaceable Parts
List:
NOTE
Resistors
R302 thru R311 are a
matched
set.
A
replacement
set
may
be
ordered
under
-hp- Part No. 03400-69502.
See
Service Note P-03400-69502 for additional
information.
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