Table of Contents
Advertisement
Section V
Paragraphs 5-22 to 5-35
the front of this manual (table 1-1).
The following
test procedure contains extra checks to help you
analyze the troubles in this instrument. These extra
checks and the data they contain cannot be considered
as specifications.
5-22. Do not perform all the tests in this procedure.
Do only those tests associated with the particular
sections of the instrument shown to be faulty by the
performance test.
Indiscriminate adjustment of the
internal controls to "refine" the settings may actually
cause trouble.
5-23. REFERE CE VOLTAGE ADJUSTME T.
5-24. To set the reference voltage proceed as follows:
a. Connect a voltmeter, such as the r.5f; Mode1405A/
B/C across C24 (reference supply filter capacitor
on board A).
b. Adjust R48 (Reference Voltage Adjust potentiom-
eter) until the meter reads 13.2 ± 0.2 volts.
c. Remove meter.
5-25. MONITORI G.
5-26. For all following tests (subparagraphs 5-27
and 5-29) the output voltage should be monitored. The
positive output terminal of the Model 722A is con-
sidered circuit ground.
To monitor the output con-
nect a voltmeter, such as the r.5f; Model 405A/B/C
as follows:
a. Turn AC and DC switches to OFF.
Remote-
Local switch on Local.
b. Turn COARSE VOLT AGE potentiometer R25
fully counterclockwise.
c. Attach voltmeter to the output terminals (front
or rear) of the Model 722A "with the black terminal
of the voltmeter connected to the red (positive) termi-
nal of the Model 722A.
(In this test procedure the
positive side of the Model 722A output is considered
circuit ground.)
5-27. VOLTAGE RANGE.
5-28. To check the voltage range of the Model 722A
proceed as follows:
a. Turn the AC and
DC
POWER switches to ON.
b. Tum the COARSE and FINE VOLTAGE controls
on the front panel fully clockwise.
The voltmeter
across the output should indicate 60.1 to 60.3 volts.
If
not, adjust R48.
c. Turn the COARSE and FINE VOLTAGE controls
on the front panel fully counterclockwise. The volt-
meter across the output should indicate 0.05 to 0.02
volt (positive terminal on the Model 722A is considered
ground).
5-6
Model 722A
5-29. CURRENT LIMIT.
5-30. A simple way to measure current with a volt-
meter is to use a load made up of a 25 ohm, 150 watt
resistor in series with a precision 1%, 1 ohm,S watt
resistor, r.5f; stock number 0811-0040. Connect a volt-
meter in shunt with this precision resistor.
In the
following procedure the term shunt voltmeter will be
used to distinguish this voltmeter from other volt-
meters.
5-31. To adjust the current limiting proceed as follows:
a. Turn the DC POWER switch to OFF.
b. Connect the load mentioned above the OUTPUT
terminals.
c. Connect the shunt voltmeter across the 1 ohm
precision resistor.
d. Turn the
DC
POWER switch to
0 •
e. Turn the CURRE T LIMIT potentiometer on the
front panel fully clockwise and the COARSE VOLTAGE
control fully counterclockwise.
f. Turn the COARSE VOLTAGE control slowly
clockwise until the current appears to limit (volt-
meter on panel stops rising).
The voltage on the
shunt voltmeter should be 2.3 volts.
If
not, adjust R20.
g. Adjust the COARSE and FINE VOLTAGE control
until the shunt voltmeter reads exactly 2.00 volts (in-
dicating 2 amps current).
h. The OUTPUT CURRENT meter should read
exactly 2.00 amps.
If
not, adjust Ammeter Calibrate
potentiometer (R16) until the OUTPUT CURRENT
meter does read exactly 2.00 amps.
i.
Turn COARSE VOLTAGE control until the output
voltage is about 10 volts and tum CURRENT LIMIT
control fully counterclockwise.
j. The voltage on the shunt voltmeter should be
0.08 volts (0.08 amp) or less.
If
not, pad R13.
5-32. PERFORMANCE TEST.
5-33. Before attempting to troubleshoot this instru-
ment make sure the fault is with the instrument and
not in the associated circuit under test. This proce-
dure will enable you to determine this without having
to remove the instrument from the cabinet. BE SURE
TO PERFORM THIS TEST BEFORE DISTURBING
A Y OF THE INTERNAL ADJUSTMENTS OF THE
INSTRUMENT.
This test may also be used as in in-
coming inspection test to make sure the instrument
has not been damaged in shipment, for periodic main-
tenance, or to check operation of the instrument
after repairs.
5-34. VOLTAGE RANGE.
5-35. To check the voltage range proceed as follows:
01155-1
Advertisement
Table of Contents
