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Model 3476A
ADJUSTMENT PROCEDURES
Section V
b. Connect an electronic counter to test point D. If the
Multimeter is to be operated from a 60 Hz line frequency,
adjust R43 for an indication of 954 Hz on the counter. For
50 Hz line operation, adjust R43 for 795 Hz.
5-30. Ohms Adjustment.
a.
Connect a jumper wire across the fuse that protects
the V/S2 terminal (F2).
b.
Set the Multimeter FUNCTION to krz and connect a
1 megohm ± 0.1% resistor to the input.
c.
Adjust R15 for a display of 999 to 1001.
d. Change the input resistor to 10 kilohm, ± 0.1%.
e.
Adjust R16 for a display of 10.03 to 10.04.
f.
Remove the jumper from the fuse.
NOTE
The resistance of the fuse is a part of the instru-
ment calibration. This is why the display is
adjusted high in Step e, with the fuse shorted.
5-31. AC Converter Gain and Zero Adjustment.
a.
Disconnect the previous setup and set the Multimeter
FUNCTION to ACV.
NOTE
To go to the 1.1 V range aild HOLD, set the
Multimeter FUNCTION to V AC, and apply
0.3 V to the input. When on the 1.1 V range,
push the HOLD pushbutton in.
b.
Apply a 1.0 V ac signal at 100 Hz to the input.
c. Adjust R48 for a display between .995 and .997.
d. Change the input level to 0.100 V ac at 100 Hz.
Adjust R9 for a display between .099 and . 100.
e.
Change the input back to 1.00 V ac at 100 Hz.
Adjust R48 for a display between .995 and .997.
f.
Change the input back to 0.100 V ac at 100 Hz.
Adjust R9 for a display between .099 and . 100.
5-32. AC High Frequency Adjustment (. 11 V range).
a.
Set the Multimeter FUNCTION to AC V.
b.
Apply a 0.1 V ac signal at 5 kHz to the input. Re-
lease the HOLD function and allow the Multimeter to auto-
range to the . 1 V range.
c.
Adjust C4 for a display between . 1000 and . 1010.
5-33. Changing the Power Line Options.
5-34. The Multnneter is capable of operating at any of the
line voltages and frequencies listed in Table 1-3, depending
upon how the instrument is wired internally. The instru-
ment contains a label identifying the line voltage and fre-
quency for which it is wired. If the instrument is to be
operated at a line voltage and frequency other than the one
for which it is wired, it is necessary to change the posi-
tion
of
jumper
wires
in
the
power
transformer
primary circuit. The clock frequency will have to be read-
justed if a different line frequency is used.
NOTE
If the jumper wires are changed, be sure to at-
tach a new label to the instrument, identifying
the new configuration.
5-35. Figure 7-2 shows the position of all jumper wires for
each line voltage. The component locator drawing of the as-
sembly identifies the position of each numbered jumper.
WARNING
Before changing the power supply jumpers dis-
connect ac power from the instrument. Power
supply jumpers should be changed by qualified
service personnel only.
5-7
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