TM 11-5820-803-12
Table 4-1. Preventive Maintenance Checks and Services (Continued)
Item
Interval
Item to be inspected
No
B
Procedure
Equipment in not ready/available if:
2
*
PSK modem.
Equipment fails to support assigned
Perform the self-test check as described in paragraph 3-5.
mission.
3
*
PSK modem.
Equipment fails to support assigned
Perform the self-test check as described in paragraph 4-4.
mission
*Do this check before each deployment to a mission location This will permit any existing problems to be corrected before
the mission starts. The check does not need to be done again until redeployment.
a. Perform after deployment, before operation and as required.
Table 4-2. (Deleted)
Table 4-3. Operational Checks.
Switch
Settings
Indicators
Required indication
Corrective action
POWER ON
Illuminated
Replace lamp
ALL
MONITOR
Illuminated
Replace lamp
indicators
ALARM RESET/ON
Hold in RESET
ALL FAULT indicators
Illuminated
Replace lamp
Audible alarm
Tone
Organizational maintenance
METER
(function
+5
MONITOR meter
46 to 54
Organizational maintenance
select switch)
-5
MONITOR meter
46 to 54
Organizational maintenance
+15
MONITOR meter
46 to 54
Organizational maintenance
-15
MONITOR meter
46 to 54
Organizational maintenance
XMT SYNTH
MONITOR meter
40 to 60
Organizational maintenance
RCV SYNTH
MONITOR meter
40 to 60
Organizational maintenance
AGC
MONITOR meter
0 to 100. no drift
Organizational maintenance
VCXO
MONITOR meter
35 to 65
Organizational maintenance
SIG/NOISE
MONITOR meter
per site requirements
Organizational maintenance
indicator(s) listed in the third column, and verify proper
4-4.
Operational Checks
operation as specified in the fourth column. If the
The following procedure, when properly performed, does
required indication is not obtained, perform the corrective
not interrupt digital traffic Do not disturb any control
action or refer the problem to organizational
setting except as directed in the procedure In the
maintenance V, indicated in the final column. Upon
sequence shown in table 4-3, set the front panel switch
conclusion of the test, return the ALARM and METER
listed in the first column to each potion listed in the
switches to their normal operating positions.
second column. For each switch position, observe the
Section III. MAINTENANCE OF PSK MODEM
4-5.
General
4-6.
Noise Test Procedures
a.
General
The maintenance procedures in this section are
accomplished at the operator/crew. category. If a
(1) The noise test procedure is
discrepancy occurs, a higher category of maintenance
performed on a regular basis to determine whether the
must be notified to repair the discrepancy.
PSK modem is operating with an acceptable bit error
rate when the signal is degraded by noise. The PSK
Change 2 4-2
