Adjustment Procedure; Test Point And Adjustment Locations; Power Supply Tests And Adjustments; Low Voltage Power Supply (A6) - HP 3580A Operating And Service Manual

Section V ADJUSTMENT PROCEDURES
Model 3580A
5-48. ADJUSTMENT PROCEDURE.
5-49. This portion of Section V contains complete Adjust-
ment Procedures for the Model 3580A Spectrum Analyzer:
POWER SUPPLY CHECKS AND ADJUST-
MENTS (Paragraph 5-53).
DISPLAY ADJUSTMENTS (Paragraph 5-68).
SWEEP ALIGNMENT AND DIAL CALIBRA-
TION (Paragraph 5-63).
LINE GENERATOR ADJUSTMENTS (Para-
graph 5-68).
I.F. FILTER ALIGNMENT (Paragraph 5-70).
AMPLITUDE CALIBRATION (Paragraph
5-74).
MIXER BALANCE ADJUSTMENTS {Para-
graph 5-81 ).
ADAPTIVE SWEEP MARKER ADJUSTMENT (Para-
graph 5-84).
5-50. TEST POINT AND ADJUSTMENT LOCATIONS.
5-51. Test point and adjustment locations are shown in
Figure 5-9 at the end of Section V. Most of the test points
and adjustments are easily accessible with the outer covers
removed. In some cases it will be necessary to remove the
inner cover and place the appropriate pc boards on
extenders. Set the 3580A POWER switch to OFF when
removing or replacing a pc assembly.
5-52. The Adjustment Procedure is written in a logical
sequence. If the instrument is known to be completely out
of calibration, the sequence should be strictly followed.
Many times, however, only certain adjustments need to be
made. The Performance Tests have been written in such a
manner that they will lead you to the proper adjustment. In
addition, a brief description of each adjustment is given.
Read through the procedures carefully, doing only those
that are necessary. Take careful note of any previous
adjustments which may affect a future adjustment.
NOTE
Alw~s test the low voltage power supply
be/ ore per/ arming any calibration. All test
measurements should be made with respect to
circuit ground, which is available at any point
on the instrument chassis. Adjustments should
not be made until the instrument has had one
hour of continuous warm-up.
5-53. POWER SUPPLY TESTS AND ADJUSTMENTS.
5-54. These tests and adjustments check the operation of
the low voltage + 10 V de and - 10 V de regulated power
5-16
supplies and set the level of the high voltage - 2915 V de
regulated power supply. The low voltage power supply tests
should be performed prior to all other adjustments. In
addition, the High Voltage - 2915 V de power supply
voltage should be tested if any of its components were
changed or if the instrument will not pass the Frequency
Tests (Paragraph 5-9) or Amplitude Tests {Paragraph 5-18)
of the Performance Tests.
5-55. Recommended Test Equipment:
AC/DC Digital Multimeter (-hp- Model 34740A and
34 702A plug-on)
High Voltage DC Probe for above multimeter, calibrated
to 1000 V DC Standard (-hp- Model 11045A Probe
and -hp- Model 740B DC Standard)
or
Precision .1
%
High Voltage Probe and appropriate DVM
(·hp- 3440A-K05 High Voltage Probe and -hp- Model
3440ADVM)
5-56.
±
10 Volt Power Supply Tests.
a. Connect the digital multimeter (DC mode 10 volt
range) to the red lead (pin 12) at the Al3 board connector.
The multimeter reading should be+ 10.000 V
±
.050 V. If
it is not, refer to the Factory-Selected Components
information in Section VII.
b. Connect the digital multimeter (DC mode 10 volt
range) to the violet lead {pin 10) at the A13 board
connector. The de voltage present should be - 10.000 V
± .050
v.
c. Test the ac ripple voltage present on the above two
leads with the digital multimeter. There should be less than
.1 m V ac difference between the reading obtained on each
lead and that obtained with a short circuit to the
multimeter.
5-57. High Voltage Power Supply Tests.
WARNING
I
The voltages involved in the following measure-
ments may cause serious injury or even death.
USE EXTREME CAUTION.
a. If a precision .1 % high voltage de probe is available,
omit this step and proceed to Step b. Otherwise, calibrate
your high voltage probe using a 1000 volt DC Standard.
Connect the probe to the digital multimeter (DC mode) and
note the reading obtained when measuring 1000 volts on
the DC Standard. Multiply this reading by 2.915 to obtain
the proper reading for 2915 volts. Record your calculation.