
MFJ-939 Plug&Play IntelliTuner Automatic Antenna Tuner
Instruction Manual
2006-2015 MFJ Enterprises, Inc.
27
APPENDICES
POWER-ON OPERATIONS
(Press and hold buttons while turning on the power.)
Press and hold + to start the self test.
POWER
TUNE
POWER
Press and hold + then press 1 time to reset factory defaults.
ALT
TUNE
POWER
Press and hold + then press 2 times to delete current memory bank.
ALT
TUNE
POWER
Press and hold + then press 3 times to perform total reset.
ALT
TUNE
POWER
Press and hold + then press 4 times to test the power-down circuitry.
ALT
TUNE
POWER
Press and hold + then press 5 times to test the relays.
ALT
TUNE
POWER
Press and hold + then press 6 times to calibrate the frequency counter.
ALT
TUNE
Press and hold + then press 7 times to calibrate the SWR bridge.
POWER
ALT
TUNE
Press and hold + + to delete current antenna memory.
POWER
ALT
TUNE
For the + operations, not pressing or pressing it more than seven times
will cancel the operation after idling four seconds, beep two times and then resume normal operation.
POWER
ALT
TUNE
Figure 13 Power-On Operations.
Resetting the Tuner
Each time the tuner is powered off, the microprocessor saves all memories and configurations to non-
volatile memory ready to be used the next time the unit is turned on and transmit power is applied. If the
tuner is not working properly, even on initial power on, try resetting to the factory defaults.
Factory Defaults
The unit is shipped with the following default settings:
•
Inductance
0 µH
•
Capacitance
0 pF on antenna side
•
Antenna
1
•
Memory
Banks 1A and 2A on
†
•
Tuning Mode
Automatic
†
† These settings are stored separately for primary memories 1 and 2.
Note:
Resetting to factory defaults does not erase the antenna memories.
To reset the tuner to these defaults:
1.
Turn off the power to the tuner.
2.
Press and hold
only
the [ALT] button while turning the power on. Both LEDs will blink until the
button is released.
3.
Within four seconds of releasing [ALT], press the [TUNE] button once.
4.
After releasing [TUNE] for four seconds, beep three times and resume normal operation.
WARNING:
If the MFJ-939 is not behaving properly or is acting erratically, try
resetting the tuner to factory defaults.