TROUBLESHOOTING PROCEDURES Continued
a. When possible, substitute faulty handsets with ones that
vehicular radio you know are good; then troubleshoot for sidetone again.
If you troubleshoot for sidetone again, and still do not hear
sidetone, get unit maintenance to check radio.
b. Check W4 cable(s).
c. Disconnect W4 cable(s) from RT.
d. Connect handset to RT DATA; then troubleshoot for
If there is still no sidetone, get unit maintenance to check
a. Set FCTN to SQ OFF.
b. Set RF to HI.
c. Turn KY-57 to OFF.
d. Turn VOL full right (clockwise).
e. Using the correct frequency or hopset, contact a local
station or distant station.
If contact is not made with a local station, change your
location and antenna positioning. Untie vehicular antennas
and try to contact local station again.
If you cannot contact a station, get unit maintenance to
check it out.
COLD START: If contact is not made when set up for cold
start, set MODE switch to SC; check for correct MAN fre-
quency, and correct TRANSEC. If contact is not made,
start troubleshooting for power source.
COMSEC If you are in secure net, Turn KY-57 to ON and KY-57
equipment MODE to C. Check KY-57 battery; then repeat this check.
If communication was good using plain text but was bad
using cipher text, get unit maintenance to check COMSEC
f. When a rushing noise and/or COMSEC alarm are heard
After approximately 7 seconds, radio should automatically
If it does not, pressing PTT twice should clear radio immediately.
If rushing noise/COMSEC alarm continues, set FCTN to
OFF , back to SQ ON, and press PTT twice again.
If problem still exists, have unit maintenance check radio.