Operation Manual

9FT-7900R OPERATING MANUAL
Cabin Engine Room  
FT-7900R
Battery
RED: Positive (+)
BLACK: Negative (–)
Mobile Power Connections
To minimize voltage drop and avoid blowing the vehicle’s fuses, connect the supplied DC
power cable directly to the battery terminals. Do not attempt to defeat or bypass the DC
cable’s fuse - it is there to protect you, your transceiver, and your vehicle’s electrical system.
Warning!
Never apply AC power to the power cable of the FT-7900R, nor DC voltage greater
than 15.8 Volts. When replacing the fuse, only use a 15-A fast-blow type. Failure
to observe these safety precautions will void the Limited Warranty on this product.
 Before connecting the transceiver, check the voltage at the battery terminals while rev-
ving the engine. If the voltage exceeds 15 Volts, adjust the vehicle’s voltage regulator
before proceeding with installation.
 Connect the RED power cable lead to the POSITIVE (+) battery terminal, and the BLACK
power cable lead to the NEGATIVE (–) terminal. If you need to extend the power cable,
use #12 AWG or larger insulated, stranded copper wire. Solder the splice connections
carefully, and wrap the connections thoroughly with insulating electrical tape.
 Before connecting the cable to the transceiver, verify the voltage and polarity of the
voltage at the transceiver end of the DC cable using a DC voltmeter. Now connect the
transceiver to the DC cable.
MOBILE INSTALLATION
INSTALLATION
Mobile Speakers
The optional MLS-100 External Speaker includes its own swivel-type mounting bracket,
and is available from your Yaesu dealer.
Other external speakers may be used with the FT-7900R, if they present the specified 8-Ohm
impedance and are capable of handling the 2 Watts of audio output supplied by the FT-7900R.
WARNNING!
Never remove the FUSE holders
from the DC cable.