Navman MCB 7270 - Manual (Page 14)

15 NAVMAN
MCB 7270 Marine CB 27 MHz Radio Operation Manual
Appendix B - Troubleshooting
1. The radio will not power up.
A fuse may have blown OR there is no power getting to the radio unit.
a) Check the power cable for cuts, breaks, or squashed sections.
b) If the power cable is fine, replace the 3 Amp fuse (1 spare fuse is supplied).
c) Check the voltage of the battery that supplies the radio (see BAT in Section 2.1). It should be at
least 10.8V DC.
2. The radio unit blows the fuse when the power is switched on.
The power wires may have been reversed.
a) Check that the red wire is connected to the positive battery terminal, and the black wire is
connected to the negative battery terminal.
3. The speaker makes popping or whining noises when the engine is running.
Electrical noise may be interfering with the radio unit.
a) Re-route the power cables away from the engine.
b) Add a noise suppressor to the power cable.
c) Use resistive spark plug wires and/or use an alternator whine filter.
4. No sound from the external speaker.
a) Check that the external speaker cable is physically connected.
b) Check the soldering of the external speaker cable.
5. BAT flashes continuously and a warning beep sounds.
The power supply to the radio is too low.
a) Press BAT to check the voltage of the battery that supplies the radio (see BAT in Section 2.1). It
should be at least 10.8V DC.
b) Check the alternator on the vessel.
6. Poor reception or excessive noise interfering with the radio signal.
The radio sensitivity and noise elimination capabilities may need adjusting. Section 2.1 provides
basic information on adjusting squelch (SQL knob), noise rejection (REJ key) and local and normal
sensitivity (LOC key). However, if you continue to have problems, try the following sequence:
a) Ensure that LOC and REJ are both off (not shown on the LCD). Turn SQL to about halfway
between the minimum and maximum settings.
b) Turn SQL slowly clockwise (right) to reduce sensitivity. If this does not solve the problem, turn
SQL anticlockwise (left) to about halfway again and continue to the next step.
c) Press REJ to start noise rejection. Turn SQL slowly clockwise (right) to reduce sensitivity. If this
does not solve the problem, turn SQL anticlockwise (left) to about halfway again and continue
to the next step.
d) Press LOC to switch into Local mode and reduce the radio sensitivity and range. Turn SQL
slowly clockwise (right) to reduce sensitivity. If this does not solve the problem, the CB antenna
may need to be moved for optimum performance in situations where the interference source
cannot be isolated or eliminated.
7. F1 is displayed when trying to transmit.
The transmission power supply is too low or too high.
a) Press BAT to check the battery voltage (see BAT in Section 2.1 for more information if necessary).
It should be at least 10.8V DC.
b) Check the alternator on the vessel.