Figure 3-3. Connecting power to OA-3633/GRC using PP-2953(*)/U and TF-523/U.
CX-4720/VRC to the male receptacle on the power
distribution box may be connected to another
distribution box (D, fig. 8-4).
piece of equipment using the CX-4721/VRC.
(b) Connect the elliptical receptacle on the
(d) Turn on and adjust the output of the dc
power distribution box to POWER INPUT recep-
power supply to 25.5 volts. Set the PWR switch on
tacle on the rear of the AM-2060(*)/GRC.
the AM2060(*)/GRC to ON when desired.
(c) The female receptacle on the power
Section II. OA-3633(*)/GRC, TROUBLESHOOTING PROCEDURES
than the positive battery terminal and it is con-
3-5. Troubleshooting OA-3633(*)/GRC
a. When the AM2060(*)/GRC resistors R6, R7,
nected to the vehicular chassis by a bonding strap.
and R8 (fig. 3-18) are charred, there will be no
( 2 ) Install Suppressor, Electrical MX-
audio output from the AM2060(*)/GRC tO the
7778/GRC in the battery distribution circuit
receiver-transmitter. These charred resistors usu-
of the vehicle. Installation procedures are pro-
ally indicate that the power cable in the vehicle
vided in TM 115195-223-15, which also covers
( u s u a l l y the CX-4720/VRC) in which the
maintenance o f the suppressor. T h e M X -
AM-2060(*)/GRC had been used, had been con-
7 7 7 8 / G R C protects the vehicle from circuit
nected incorrectly to the vehicular battery. That
overload (short circuit) in the radio (and inter-
is, the CX-4720/VRC negative leads (blue-green)
com) equipment and the radio (and intercom)
had been connected to the battery positive termi-
equipment from electrical transient voltages in
nal, and the positive leads (red-white) had been
the vehicle electrical system.
connected to the battery negative terminal. To
b. When trouble is suspected in the application
prevent incorrect battery connections, the follow-
of operating dc voltages to the receiver-transmit-
ing precautionary procedures are recommended:
ter that was used with the AM-2060(*)/GRC,
(1) Mark the battery terminals of the vehicu-
check the AM2060(*)/GRC output circuits by
lar battery power cable so that the person that re-
performing measurements of the output voltages
places the cable leads to the battery knows the
and resistances at connector J2 (para 38, fig.
positive power cable lead(s) and the negative
power cable lead(s). The battery negative termi-
c. When trouble is suspected in the audio ampli-
nal can be identified by the fact that it is smaller