TM 11-6625-847-45
Item
No.
Indication
Probable trouble
Procedure
of -33 volts dc. If -30
volts dc is not indicated,
check capacitors A3C5 and
A3C6 and inductor A3L2
for defects. Replace de-
fective parts.
8
The AN/USM-140(0)
Same as 7b above ------------------ Check -33 volt dc filter circuit
shows excessive ripple
components for defects as
for -33 volt dc output.
described in 7b above. Re-
place defective parts.
9.
The ME-26(*)/U does
a. Connect the ME-26(*)/U
not indicate +125-volt
circuit of +125-volt dc
between terminal A3E9
dc level when TEST
output.
and ground, and check
SELECTOR switch is
for an indication of +125
set to position 3; how-
volts dc. If +125 volts dc
ever, the ME-26(*)/
is not indicated, check
U indicates -33 volt
diodes A3CR1 through
dc and +6.3-volt ac
A3CR4 for defects. Re-
levels for their re-
place defective parts.
spective TEST SE-
LECTOR switch posi-
tions.
b. Defective +125 volt dc filter
b. If +125 volts dc is indicated
circuit.
in a above at terminal
A3E9, connect the ME-
26(*)/U to test point A3J1
and ground. Check for an
indication of +125 volts dc.
IF + 125 volts dc is not in-
dicated, check capacitors
A3C1 through A3C3, in-
ductors A3L1 and L2, and
resistor A3R1 for defects.
Replace defective parts.
10
The AN/USM-140(*)
Same as 9b above ------------------ Check + 125-volt dc filter cir-
shows excessive ripple
cuit parts for defects as de-
for +125-volt dc output.
scribed in 9b above. Replace
defective parts.
2-19. Troubleshooting Chart, Test Set (Pulse Generator Module A1A1
Item
No.
Indication
Probable trouble
Corrective measures
1
Amplitude of 150 usec
Defective AMPLITUDE con-
Replace defective potentiometer
and 85-usec pulse
trol R1.
R1.
outputs does not vary
when potentiometer
R1 is rotated from
fully counterclockwise
to fully clockwise.
Change 1 2-10
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