Waveform Checks of A5Al, A4A1, A2, A3, A4 and A5 Component Assemblies and Modules

TM 11-6125-259-30

between 393 and 407 Hz.

component assemblies and modules. See figures

h. Connect the oscilloscope and counter to pins

3-11 through 3-16, as applicable, for location of

13(+) and 15(-) of Component assembly A6. The

referenced pins.

observed waveform shall be as shown in figure 3-3

WARNING

and the counter shall indicate a frequency between

High Voltage and currents are present

393 and 407 Hz.

on disassembled inverter when it is

i. Connect the oscilloscope to pins 11(+) and 8(-),

energized. Do not touch any exposed

pins 10(+) and 9(-) or 18(+) and 19(-) of com-

wiring or any metal point within the

ponent assembly A6. The observed waveform shall

inverter. Lethal shock could result.

be as shown in figure 3-3.

a. Remove top cover in accordance with para

3-9 b.

j. Connect the oscilloscope to pins 15(+) and 7()

of component assembly A6. The observed waveform

h. Disconnect wire at pin 13 of component

shall be as shown in figure 3-2, except the am-

assembly A5A1 and connect a 30 vdc power supply

plitude shall be approximately 5 volts.

to pins 12(+) and 14() of component assembly

A5A1. Adjust power supply voltage to 25.0 2.O

(1) Set A switches, S1, S2, S3 and S4 to up (on)

vdc.

position.

C. Connect Oscilloscope AN/USM-281 to pins 10

(2) Set A switch S5 to up (200% OL) position

and 11, 12 and 13 and 14 and 15 of component

and observe that above waveform goes to 0 volts in

assembly A4A1. At each connection the observed

5 to 15 seconds. Observe that within 1 to 1.5

waveform shall be as shown in figure 3-4.

seconds after waveform goes to 0 volts, it returns to

d. Connect the oscilloscope to pins 16 and 17, 18

normal and then cycles off and on at about a one-

and 19 and 20 and 21 of component assembly A4A1.

second rate.

At each connection the observed waveform shall be

(3) Set A switches Sl and S5 to down position.

as shown in figure 3-5.

k. Connect the oscilloscope to pins ll(+) and 7(-)

e. Connect the oscilloscope to pin 4 and Q207-E

of component assembly A6. The observed waveform

of module A2. The observed waveform shall be as

shall be as shown in figure 3-3, except the am-

shown in figure 3-6.

plitude shall be approximately 5 volts.

f. Connect the oscilloscope to pin 4 and Q307-E of

(1) Set A switch S10 to up (SHORT) position

module A3. The observed waveform shall be as

and observe that above waveform shall convert to a

shown in figure 3-6.

square wave with a frequency between 393 and 407

g. Connect a 40 vdc, 5 amperes power supply to

Hz.

pins l() and 5(+) of module A4. Adjust power

(2) Set A switch S10 to down position and

supply voltage to 10.0 0.5 vdc.

observe that waveform drops to 0 volts and returns

h. Connect the oscilloscope to pins 1 and 2, 4 and

to level of figure 3-3.

7 and 8 and 9 of component assembly A4A1. At

l. Set UNIT PWR switch S6 to down position.

each connection the observed waveform shall be as

Connect the oscilloscope to pins 15(+) and 7() of

shown in figure 3-7.

assembly A6. Set UNIT PWR switch S6 to up (ON)

i. Connect the oscilloscope to pins 22 and 23, 25

position and observe that waveform shall be 0 volts

and 28 and 29 and 30 of component assembly A4A1.

for approximately 1 second before displaying a 400

At each connection the observed waveform shall be

Hz square wave.

as shown in figure 3-8.

m. Set UNIT PWR switch S6 to down position.

j. Increase 40 vdc power supply voltge to 37.0

Disconnect inverter from test fixture.

0.5 vdc and repeat i above. The observed

n. If required at this time, carefully lay A7

waveform shall be as shown in figure 3-8 except the

component assembly (17) back in place on top of A6

peak-to-peak voltage shall be approximately 74 vdc.

assembly (16); be careful of interconnecting wiring.

k. Increase 40 vdc power supply voltage to 39.0

Install A7 assembly with six screws (20), six

0.5 vdc. Using a X10 probe, connect oscilloscope

lockwashers (21) and six flat washers (22).

to pins 22 and 25, 23 and 26, and 24 and 27 of

o. Reassemble bottom cover in accordance with

module A5. The observed waveform shall be as

para 3-10 m, if required at this time.

shown in figure 3-9.

3-3. Waveform Checks of A5Al, A4A1, A2, A3,

l. Turn off and disconnect 40 vdc power supply.

A4 and A5 Component Assemblies and

Reduce the 28 vdc input voltage to 0. Turn off and

Modules

disconnect the 30 vdc power supply.

m. Solder wire back to pin 13 of component

The instructions in this paragraph are performed

assembly A5A1.

only if internal inverter waveforms are required to

n. Reassemble top cover in accordance with para

be checked on A5A1, A4A1, A2, A3, A4 and A5

3-10 n.

3-3