A +7 V Power Supply Adjustment (R417); B U725 Back Gate Bias Adjustment (R603); Clock Frequency Adjustment (R9); Ac Zero Adjustment (R203) - HP 3438A Operating And Service Manual

Section V
@
D C Gain Adjustment (R403).
@
O H M S Gain Adjustment (R119).
@
A C Gain Adjustment (R123).
@
20 V a c Range, 20 k H z Adjustment (R102).
@
2 V a c Range 20 k H z Adjustment ( R I 10).
@
20 V a c Range 100 k H z Adjustment (C109).
5-13.
1 A
+ 7
V
Power Supply Adjustment
(R417
9
a. Place d c 1)VM probe tip on the
+
7 V test pad o r
+
end of C407.
b. Adjust K417 lor a d c D V M rrading of
+
7
k
0.01
volts (6.99 t o 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.
- 6 9 t o - 7 1 V
2 V (V
SUB)
- 1 9 t 0 2 1 V
I
ti
5 (V
DISP)
6 1 8 t o 6 8 3 V
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 d c Digital Voltlnctcr ( U V M ) to J M V H
( A 3 I' C assembly).
b. ,ldju$t 1<603 l'or a d c I>VM rending equal to the
loltage \tamped o n A311725.
NOTE
Model 3438A
5-15.
@
Clock Frequency Adjustment (R9).
a . Connect a 10 Mi1 ( I 0 : I divider) oscilloscope probe
from the 5300A 5302A l'requrncy counter input t o J M 2
on the Multirneter A l 1'C assembly.
b. Adjust K9 l'or-
a
frequency counter reading of 9980
I I / to 10020 H / ( I 0 k H / -t . 2 ( i ) .
5-16.
@
AC Zero Adjustment (R203).
a. Set the Multirnetrr to a c V, 20 V range.
b. Connect a short across the V 11 to C O M terminals.
c. Adjust K203 l'or a Multimcter display reading of
00.0 V.
5-17.
@)
20 Ohms Zero Adjustment (R111).
a. Set the Multirneter t o ac V 200 V range.
b. Connect
;I
short acro$s thc V 11 to C O M terminals.
NOTE
[
'.\ll (1
/Oil'
r l ' \ i . \ / ~ / l i ' l ' . \ / l ~ J ~ / ~ ~ O / l l / ~ ~ ~ \ l ~ l / i J / / l l ~ ~ l ~ l ~
C O / J / ) C ~
11.ir1, .\o/c/oro(/ (~c,ro.~.i
( I ( / O L I / I / P / ~ u t ~ u r i ( i
c
oriric'i'~or.
c. Adjust R I I I lor a Multinieter dijplay rrndinp of
0.00 ohms.
5-18.
@
D C Gain Adjustment (R403).
a. Set the Multimetcr to d c V, 20 V rangc.
b. Set thc 740H d c standard as
folio\\\:
I- ~ ~ n c t ~ o n Std
I < , ~ ~ l g e
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.
D C STANDARD MULTIMETER
h p 3438A
O O O O O C 00000000
OUTPUT CABLE
C 3
@
h p 1 1 0 5 5 8
-
3 4 3 5 B 4 6 1 7
Figure
5-1.
DC Gain Adjustment.
5-2