Section V
@
DC Gain Adjustment (R403).
@
OHMS Gain Adjustment (R119).
@
AC Gain Adjustment (R123).
@
20 V ac Range, 20 kHz Adjustment (R102).
@
2 V ac Range 20 kHz Adjustment (RI 10).
@
20 V ac Range 100
kHz
Adjustment (C109).
5-13.
1
A
+7
V
Power Supply Adjustment
(R417
9
a. Place dc 1)VM probe tip on the
+
7 V test pad or
+
end of C407.
b. Adjust K417 lor a dc DVM rrading of
+
7
k
0.01
volts (6.99 to 7.01 bolts).
c. Check the power supply voltages listed in Table 5-2
to verify the tolerances indicated.
Table
5-2.
Power
Supply
Voltage Checks.
-69to-71 V
2
V (V
SUB)
-1
9t021 V
I
ti
5
(V
DISP)
618to683V
r
9
V (V
D)
8
55
to
9
45
V
5-14.
1
B
U725 Back Gate Bias Adjustment
(R603
9
a.
Connect a dc Digital Voltlnctcr (UVM) to JMVH
(A3
I'C assembly).
b.
,ldju$t 1<603 l'or a dc I>VM rending equal to the
loltage \tamped
on
A311725.
NOTE
Model 3438A
5-15.
@
Clock Frequency Adjustment (R9).
a. Connect
a
10 Mi1 (I0:I divider) oscilloscope probe
from the 5300A 5302A l'requrncy counter input to JM2
on
the Multirneter A
l
1'C assembly.
b. Adjust K9
l'or-
a
frequency counter reading of 9980
II/
to 10020
H/
(I0
kH/
-t
.2(i).
5-16.
@
AC Zero Adjustment (R203).
a.
Set the Multirnetrr to ac V, 20 V range.
b.
Connect a short across the V 11 to COM terminals.
c. Adjust K203 l'or a
Multimcter display reading of
00.0
V.
5-17.
@)
20 Ohms Zero Adjustment (R111).
a. Set the Multirneter to
ac
V 200 V range.
b. Connect
;I
short acro$s thc V 11 to COM terminals.
NOTE
[
'.\ll
(1
/Oil'
rl'\i.\/~/li'l'.\/l~J~/
~~O/ll/~~~\l~l/iJ//ll~~l~l~
CO/J/)C~
11.ir1,
.\o/c/oro(/
(~c,ro.~.i
(I
(/OLI/I/P
/~ut~uri(i
c
oriric'i'~or.
c. Adjust RI
I I
lor a Multinieter dijplay rrndinp of
0.00
ohms.
5-18.
@
DC Gain Adjustment (R403).
a. Set the Multimetcr to dc V, 20 V rangc.
b. Set thc 740H dc standard as
folio\\\:
I-
~~nct~on Std
I<,~~lge
100
\'
Output \olt;lgc lC~.O0O
(\')
c.
Connect the 740H output to the Multimctcr input a\
\ho\r
n
in Figure 5- 1.
d. Adjust R403 lor
a
Multi~nctcr dlhplay reading
ot
19.00 V.
DC STANDARD
MULTIMETER
hp
3438A
OOOOOC
00000000
OUTPUT
CABLE
C3
@
hp110558
-
3435
B
4617
Figure
5-1.
DC Gain Adjustment.
5-2
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