MIL-DTL-52876D
APPENDIX A
TEST METHOD 2
1 ZONE POWER SUPPLY
FUNCTIONAL TESTS
1.
TEST APPARATUS:
a.
Oscilloscope (scope)
Tektronix model 2225 or equivalent.
b.
Voltmeters, dc (M2, M3, M4)
3-1/2 digit or greater, minimum accuracy 0.25
percent of reading ± 1 least significant digit
(LSD).
c.
Voltmeters, ac (M1, M5)
3-1/2 digit or greater, minimum accuracy 0.25
percent of reading ± 1 LSD.
d.
Power supply (PS1)
Hewlett-Packard Model 6291A or equivalent.
e.
Autotransformer (VR1)
General Radio Model W20M or equivalent.
f.
SPST switches (S1-S7)
Leviton Model 19916 or equivalent.
20K ohm ±5 percent, 1/4 watt.
g.
Resistor, 20 Kilohm (R1)
h.
Resistor, 160 ohm (R2)
Ohmite, 200 ohm, adjustable, 12 watts, type
210-12, P/N D12K200 or equivalent.
i.
Resistor, 80 ohm (R3)
Ohmite, 100 ohm, adjustable, 12 watts, type
210-12, P/N D12K100 or equivalent.
j.
Resistor, 270 ohm (R4)
Ohmite, 300 ohm, adjustable, 12 watts, type
210-12, P/N D12K300 or equivalent.
k.
Resistor, 15 ohm (R5)
Ohmite, 25 ohm, adjustable, 175 watts, type
210-175, P/N D175K25R or equivalent.
l.
Ammeter, dc (see note)
3-1/2 digit or greater, minimum accuracy 0.75
percent of reading ± 1 LSD, 4 amperes minimum.
m.
Test fixture.
(See figure 1).
NOTE:
Item l. is required only for calibrating test fixture resistors.
2.
TEST PROCEDURE:
2.1 When this test is being performed as part of the monitor cabinet
functional test, remove the power supply from the cabinet prior to performing
the test procedure.
3.
TEST PROCEDURE
3.1
Output voltage levels.
a.
Connect the power supply under test (PSUT) in the test fixture as shown
in figure 1. Set the PSUT power switch in the "OFF" position and apply
117 Vac, 60 Hz line power to the autotransformer (VR1).
b.
Open switches S1 through S7.
c.
Adjust the VR1 for 117 Vac on M5.
d.
Close S4.
e.
Place the PSUT power switch in the "ON" position. Allow at least 15
minutes warm-up before proceeding with test.
f.
The following output voltage levels shall be observed:
Location
Meter
Voltage
Output
20 ±1 Vdc
1
TB3-2 to TB3-5
M2
2
TB2-2 to TB2-1
M3
See below
22.5 ±3.5 Vac
3
TB3-1 to TB3-6
M1
Output 2: 27.9 ±0.3 Vdc at 77 ±5 °F, 30.2 ±0.7 Vdc at -20 °F, 25.6 ±0.7 Vdc
at +150 °F, and 27.5 ±0.7 Vdc during humidity test.
16
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