MFJ-926B HF Automatic Remote Antenna Tuner
Instruction Manual
2010 MFJ Enterprises, Inc.
14
8. After releasing [TUNE] for four seconds and if the power-down detection circuitry is okay, a
repetitive message “PASS” will be sent in Morse code (di-dah-dah-dit di-dah di-di-dit di-di-dit)
by blinking the green LED. If there is a problem, message “PD FAIL” will be sent in Morse code
repetitively and the red LED will blink.
9. Turn the power off.
Relay Test
WARNING:
Turn off the transmitter power or disconnect the transmitter before performing
this test; otherwise, damage to the tuner can result.
To test the relays and their control circuitry;
1. Turn off the power to the tuner.
2. Press and hold
only
the [ANT] button while turning the power on. Both LEDs will blink until the
button is released.
3. Within four seconds of releasing [ANT], press the [TUNE] button five times.
4. After releasing [TUNE] for four seconds, Flash once and the Relay Test routine is initiated.
5. Press the [TUNE] button to engage the relay and the red LED will turn on. Release the [TUNE]
button to disengage the relay and the red LED will turn off. Listen for relay clicks.
6. There are 19 relays in the tuner. Press the [ANT] button to test the next relay. The green LED
will illuminate until the [ANT] button is released.
7. Repeat Steps 5 and 6 to test all 19 relays (in the order of relay K1 to K19).
8. After releasing [ANT] on the 19
th
relay, Flash three times and resume normal operation.
Frequency Counter Calibration
To calibrate the frequency counter, you will need a transmitter, a 50-ohm dummy load, two 50-ohm SO-
239 coax cables, a Phillips screwdriver, and a tuning tool or small flat blade screwdriver.
WARNING:
Do not touch anything inside the tuner during operation! Serious, painful RF
burns can result.
WARNING:
Never operate the MFJ-926B with its cover removed; dangerous voltages and
currents can be present during operation. Never exceed tuner specifications.
1. Turn off the power to the transmitter and the tuner.
2. Remove the cover from the tuner (6 screws) with a Phillips screwdriver.
3. Connect the transmitter to the
“RF IN/OUT”
coaxial connector on the
MFJ-4117 Bias-Tee
using a 50-ohm coaxial cable. (See Figure 1) This is the RF signal input connector.
4. Connect a 12-15 VDC voltage source capable of supplying at least 750 milli-amps to the “
DC
IN\OUT”
jack on the
MFJ-4117 Bias-Tee.
This is your DC voltage input connector.
5. Connect the
“RF/DC OUT/IN”
coaxial connector on the
MFJ-4117 Bias-Tee
to the
TRANSMITTER
connector on the
MFJ-926B Intellituner
using 50-ohm coaxial cable. The
MFJ-926B Intellituner
will recover the RF and DC signals.
6. Connect a 50-ohm dummy load to the
ANTENNA
connector using a 50-ohm coaxial cable.