Performance Check/Calibration—Type 422 AC-DC
f. Set the autotransformer output voltage to 95 or 190)
volts.
g. CHECK—Output voltage of each supply with the
precision DC voltmeter for the tolerances given in Table
5-1.
h. Set the autotransformer output voltage to 137 (or
274) volts.
i. CHECK—Output voltage of each supply with the
precision DC voltmeter for the tolerances given in Table
5-1.
j. Disconnect the precision DC voltmeter and use the
test oscilloscope with IX probe for parts m through q.
k. CHECK—Ripple of each supply for AC ripple
tolerances given in Table 5-1.
l. Set the autotransformer output voltage to 95 (or 190)
volts.
m. CHECK—Ripple of each supply for AC ripple
tolerances given in Table 5-1.
n. Set the autotransformer output voltage to 115 (or
230) volts.
o. CHECK—Ripple of each supply for AC ripple
tolerances given in Table 5-1.
p. Disconnect the voltmeter.
7. Check Battery Charger Operation
a. Turn off the AC power to the instrument.
b. Set the Power Mode switch (rear panel) to CHARGE
BATT 115V AC (use CHARGE BATT 230V AC for
230-volt nominal line).
c. Connect the 50-ohm 10-watt resistor to one of the
battery terminals (see Fig. 5-6A) with the six-inch jumper
lead. Connect the ammeter between the remaining battery
terminal and the other side of the resistor. Position all leads
so a short-circuit condition does not exist.
d. Set the autotransformer output voltage to 95 (or 190)
volts and re-apply the AC power.
e. CHECK—Ammeter reading; 325 milliamperes mini
mum.
NOTE
Do not leave the instrument on in this condition for
extended periods of time as the high current through
the external resistor may cause it to overheat. If the
resistor becomes overheated, turn off the power and
allow it to cool before continuing.
f. Set the autotransformer output voltage to 126.5 (or
253) volts.
g. CHECK—Ammeter reading; 450 milliamperes maxi
mum.
h. Turn off the AC power to the instrument.
i. Replace the 50-ohm resistor with a 680-ohm two-watt
resistor.
j. Set the Power Mode switch to OPERATE 115V AC
(use OPERATE 230V AC for 230-volt nominal line).
k. Turn on the AC power.
l. CHECK—Ammeter reading; 30 to 50 milliamperes.
m. Set the autotransformer output voltage to 95 (or
190) volts.
n. CHECK—Ammeter reading; 30 to 50 milliamperes.
o. Turn off the instrument and disconnect all test
equipment. If the AC line voltage available is not about 115
(or 230) volts, leave the autotransformer connected to the
instrument and set it for 115 (or 230) volts.
8. Check High-Voltage Supply
a. With the AC power off, remove the plastic cover from
the CRT socket.
b. Connect the DC voltmeter (VOM) from the
high-voltage test point (pin 3 of CRT socket, see Fig. 5-7)
to chassis ground.
c. Return the POWER switch to ON (at power supply).
d. CHECK—Meter reading; —1385 volts ±69.5 volts.
e. Disconnect the voltmeter and replace the plastic
cover.
9. Adjust Unblanking Center
a. Change the following control settings:
INTENSITY Midrange
TRIGGERING Mode AUTO (pushed in)
b. ADJUST—Unblanking Center adjustment R869 (see
Fig. 5-8) for maximum trace intensity. This should occur
near the center of adjustment range.
10. Check/Adjust Trace Rotation
a. Position the trace to the center horizontal line with the
Channel 1 POSITION control.
5-13
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