Performance Check/Calibration—Type 422 AC-DC
Fig. 5-5. Typical test oscilloscope display of power-supply ripple
(sweep rate 20 microseconds/division).
5. Adjust Low-Voltage Indicator
a. Set the Power Mode switch (rear panel) to OPERATE
I NT BATT.
b. Connect the variable DC power supply positive
output to the bottom battery-interconnection banana plug
(see Fig. 5-6) with an 18-inch dual banana plug-jack patch
cord. Connect the negative output to the top battery-
interconnection banana plug with another 18-inch dual
banana plug-jack patch cord.
c. Connect the precision DC voltmeter to the battery-
interconnection banana plugs.
d. Set the variable DC power supply for about +35 volts
output.
e. CHECK-POWER light (front panel of indicator) is on
and does not blink.
Fig. 5-6. (A) Location of battery-interconnection banana plugs (rear
of power supply), (B) location of low-voltage indicator adjustment
(DC Power Control board).
f. Slowly decrease the output voltage of the variable DC
power supply.
g. CHECK—POWER light begins to blink when power
supply output voltage is 22 volts +0, —1 volt as indicated
by the precision DC voltmeter.
h. ADJUST—With the variable DC power supply set to
exactly +22 volts, set the Low-Voltage Indicator adjust
ment R1047 (see Fig. 5-6B) clockwise until the POWER
light is on steady. Then, slowly adjust this control
counterclockwise until the POWER light just begins to
blink.
i. Recheck parts d through g of this step.
j. Disconnect all test equipment.
6. Check AC Operation
a. Set the Power Mode switch (rear panel) to OPERATE
115V AC (use OPERATE 230V AC for 230-volt nominal
line).
b. Connect the autotransformer to an AC line voltage
source.
c. Set the autotransformer output voltage to 115 (or
230) volts.
d. Connect the AC-DC Power Supply to the autotrans
former output with the AC power cord.
e. CHECK—Output voltage of each supply with the
precision DC voltmeter for tolerances given in Table 5-1.
5-12
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