TM 11-5820-890-20-1
3.1.
OPERATIONAL CHECK. Continued
IMPORTANT POINTS TO REMEMBER IN USING THE OPERATIONAL CHECK
When an Operational Check step involves an item of equipment which is not used in the system being
checked, skip the appropriate portion of that step and continue to the next step.
It is important that Operational Check steps be performed as stated and in the order presented in the
manual.
If the vehicular radio system being checked includes an AN/VIC-1 (VIC) intercom, determine as early
as possible whether the problem is in the VIC or the radio; then troubleshoot that part of the system. If you
need to troubleshoot the VIC, see Chapter 2 TM 20-2.
Once you have completed the Operational Check, and the problem appears to be solved, make a
communications check (unless prohibited by unit SOP or the tactical situation) and repeat the Operational
Check to ensure the system is completely operational.
When removing or installing components ensure VAA CB1 is in OFF position.
Do not accept power outputs less than those specified.
Before beginning an Operational Check on any vehicular radio system, verify that you have good power
with engine running and engine off. Obtain assistance of unit vehicle mechanic as required.
OPERATIONAL CHECK FOR VEHICULAR RADIOS
(Short Range RT-A, RT-B, and Long Range RT-A, RT-B)
STEP 1. PREPARATION:
STEPS TO PERFORM
1.1
Set RT:
FCTN to OFF
CHAN to MAN
MODE to SC
RF PWR to HI
VOL to Mid-Range
DIM to Full CW
COMSEC to Z
CHECKS TO MAKE
N/A
N/A
N/A
N/A
N/A
N/A
N/A
ACTIONS TO TAKE
N/A
N/A
N/A
N/A
N/A
N/A
N/A
1.2
Set Vehicular Amplifier-Adapter
(VAA):
CB1 to OFF
DS1 to Full CCW
AM-7239 Series:
If LS-671 or VIC is used:
If neither is used:
N/A
N/A
Ensure VAA is set to REMOTE.
Ensure VAA is set to LOCAL.
N/A
N/A
N/A
N/A
1.3
Set all LS-671 Loudspeakers:
CB1 to OFF
DS1 to Full CCW
VOL to OUT/Mid-Range
N/A
N/A
N/A
Ensure that HS used is operational *
N/A
N/A
N/A
N/A
N/A
Install known good HS
N/A
N/A
*
And disconnect all other HS.
**
If AM-7239/C/D/E are used, disconnect W-4 from VAA and RT. Connect H-250 to RT AUD/DATA. W-4
only needs to be connected when transmitting Packet Data.
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