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TM 11-5820-890-30-5
4-9.
OPERATIONAL CHECK. Continued
Step 3. AUDIO AMPLIFIER CHECK FOR AM-7239/VRC AND AM-7239B/VRC. Continued
Action
Response
y. Connect cable at J5 to J4.
y. Scope reading is 0.8 to 1.3 V dc when
Set STIM SEL: HANDSET.
PTT: UUT, then -0.2 to 0.2 V dc within
Set PTT: UUT. Read scope.
1 second. If no signal is present, go to
chart 19. If a signal is present but not
correct, the audio amplifier (5A2) is bad.
z. Set PTT: OFF.
z. No response.
aa. Set STIM SEL: FCTN GEN.
aa. Scope reading is 0.8 to 1.3 V dc. If signal
Set PTT: UUT. Read scope.
is same as in step 3 y, go to chart 20. If
not, the audio amplifier (5A2) is bad.
ab. Set PTT: OFF.
ab. No response.
ac. Set LOAD: OFF.
ac. Record current measured by DMM.
Set CB1: OFF.
Set 28 V: OFF.
Disconnect BNC-to-banana adapter from
DMM. Connect test leads to DMM, and
set DMM to 2000 mA scale. Insert (+)
test lead into TEST POINT 6. Insert (-)
test lead into TEST POINT 7.
Set CB1: ON. Read DMM.
ad. Set LOGIC: 1. Read DMM.
ad. DMM reading is 200 to 800 mA greater
than that recorded in step 3 ac. If not,
go to chart 21.
ae. Set LOGIC: 4.
ae. No response.
af. Disconnect cable at J8 and move it to J7.
Set LOGIC: 1. Read DMM.
af. DMM reading is 200 to 800 mA greater
than that recorded in step 3 ac. If not,
go to chart 22.
Step 4. POWER AMPLIFIER INTERFACE FOR AM-7239/VRC AND AM-7239B/VRC.
Action
Response
a. Set CB1: OFF.
Disconnect cable at J7 and move it to J8.
a. DMM reading is less than 5 W. If not,
go to chart 23.
Remove test leads from TEST POINTS 6
and 7 and DMM. Connect BNC-to-banana
adapter to DMM.
Set TEST EQPT SELECTOR: DMM.
Set RESPONSE: 6.
Set RESP SEL: S2. Read DMM.
b. Disconnect cable at J1 and move it to J11.
b. DMM reading is less than 5 W. If not,
Disconnect cable at J8 and move it to J7.
go to chart 24.
Read DMM.
4-11
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