Marine Radio Tech Tips

Charge Contacts in Handheld Radios
Symptom: “Brand X” rechargeable batteries do not charge.     Numerous models of Cobra handheld radios have a special feature which prevents accidentally ...
Connecting a GPS Device to the MR F45 / 55 / 75
This can be tricky because different manufacturers use different wiring schemes. Therefore we can only provide general recommendations.   Your Cobra radio...
Connecting a GPS Device to the MR F57
This can be tricky because different manufacturers use different wiring schemes. Therefore we can only provide general recommendations.   The MR F57 comes...
MR F57 / MR F77 "Check Plotter" Alarm
SYMPTOM: The radio keeps beeping and it says “Check Plotter” on the display. These symptoms indicate that the blue wire has been accidentally gro...
MR F57 / MR F77 "Demo Mode"
If an MMSI number has not been entered then the below screen will appear each time the radio is turned on.   If the DEMO button is pressed then the radio ...
MR F75 - Connections for External Speaker / PA Speaker
A 3.5mm (1/8”) stereo plug is required. Do not use a mono plug. Connections are as follows: The tip is the speaker output.  The center conductor is th...
Connecting a GPS Device to the MR F77
NOTE: The MR F77 has a built-in GPS receiver. An external GPS connection should not be needed unless the radio is installed at a location where it does not ...