Cover Removal And Replacement; Meter Mechanical Zeroadiustment; Input Impedance Check Setup - HP 400F Operating And Service Manual

Section V
paragraphs 5-21 to 5-29 and Figures 5-3 to 5-4
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specifications. The following procedures specify the
use ol an -hp- 736BR Voltmeter Calibrator and an -hp-
652A Test Oscillator. However, an -hp- K02-736BR
VTVM Calibration System may be substituted by fol­
lowing the same general procedures.
ment cannot be properly adjusted, refer to Para­
graph 5-39. Troubleshooting Procedures. Refer to
Figure 5-4 for the location of internal adjustments.

5-21. COVER REMOVAL AND REPLACEMENT.

5-22. Removal of the top cover exposes circuit areas
for routine checks and adjustments. Removal
bottom and side covers exposes circuit areas for opera­
tions such as soldering and component replacement.
5-23. TOP OR BOTTOM COVERS.
a. Remove screw at rear
about 1 inch to rear, and lift it off.
b. To replace cover. reverse the removal pro­
cedure.
AICZ
UOOKHz
IV CALl (400Hz IV CALl
5-4
TEST OSCILLATOR
hp 652A
0
Figure 5-3. Input Impedance Check Setup
If
the instru­
of
the
of
cover. Slide cover
A2R6
AIR7
(AZQI BIAS AOJI
A2R�9
(20HI 3OMV CAL)
Figure 5-4. Loc?tion of Internal Adjustments
P
400F/FL
AC VOLTMETE
5-24. SIDE COVER.
5-25. Remove the lour screws from side cover,
it
and lift off.
5-26. METER MECHANlCAL ZERO ADJUSTMENT.
5-27. Refer to Paragraph 3-5 for the meter mechanical
zero adjustment procedures.
5-26. METER CALIBRATiON.
5-29. The following procedures are used to adjust the
gain of the meter amplifier on two voltage ranges at
five different frequencies. Proper gain adjustments
will assure accurate meter indications over the entire
voltage and frequency range of the instrument. Use
the test setup shown in Figure 5-1 for the meter cali­
bration.
AZR6Z
AZR�B M (400HZ
.
(lOHI O I V CAll
A2ClB
(4101Hz
lOhlV CAL)
ModeI 400F/FL
R
AZR68
lOMV CALl
1400Hz O.lhlV CAL)
01795-1