SEA 222 Operator's Manual page 38

4.3.4
4.3.5
MIC - Input for a dynamic microphone in parallel with supplied palm
microphone. (In some cases, the standard microphone may be discon-
nected when this terminal is used.)
-
-
PTT - Input to the transmitter keying circuit. By apP.,lying ground
potential to this terminal, the PTT relays are activated.
13V - 13 Volts, switched through the normal ON/OFF switch of the
SEA 222. Normally used to power an externa
1
antenna coup
1
er such as
the SEA 1612. DO NOT EXCEED 3 AMPS. The fuse for this circuit is the
5 AMP fuse located on the PA/Filter Board,
ASY~0222-02.
TND - This terminal allows the connection of an "ALL TUNED" indicator
line from an automatic antenna coupler. Grounding this line will cause
the "TUNED" indicator in the VF display to light. (See ~ 2.5.)
GND - Access to the negative side (ground) of the primary supply.
Also common to the chassis.
DO NOT USE THESE TERMINALS FOR HIGH CURRENT APPLICATIONS.
FUSING
Three fuses are· provided
in
the SEA 222, all mounted internally on
the PA/Filter Board (ASY-0222-02).
Fuses Fl and F2 are 15 AMP, 3AG fast bl ow fuses. Each fuse protects
one pair of power output transistors, and each fuse is provided with a
reverse polarity protection diode.
Fuse F3 is a 5 AMP, 3AG fast bl ow fuse. This fuse protects the low
level circuitry in the SEA 222 and also provides a fused 13 Volt power
buss for an external antenna coupler. This fuse is also provided with
a reverse polarity protection diode.
THE GROUND CONNECTION
A stainless steel bolt and nut are provided on the rear panel to
allow a low resistance connection between the radiotelephone chassis
and the engine block, keel or similar RF ground system.
I