MFJ-269 Instruction Manual HF/VHF/UHF SWR Analyzer
6
2.2
Using Internal Batteries
When batteries are initially installed, a small black-plastic internal jumper must be re-positioned or checked for
proper position. The battery setting jumper is located inside the unit at the top of the printed circuit board near
the area of the OFF-ON switch and power connector. This jumper is accessed by removing eight screws along the
both sides of the MFJ-269. After the cover mounting screws are removed, remove the entire back cover. The
black plastic jumper fits over two of three adjacent pins. It must be properly positioned for the type of battery
used (either rechargeable or non-rechargeable).
For battery replacement, batteries are accessed by removing the MFJ-269’s cover. Be sure the charger switch is
in the correct position when replacing batteries.
2.3
Using Rechargeable “AA” Type Batteries
CAUTION: A
VOID USING EXTERNAL POWER SOURCES HAVING LESS THAN 13
VOLTS IF RECHARGEABLE BATTERIES ARE INSTALLED. IF EXTERNAL
SUPPLY VOLTAGE IS TOO LOW, THE CHARGER WILL NOT WORK
PROPERLY AND BATTERIES WILL EVENTUALLY DISCHARGE. WE
RECOMMEND RECHARGING DISCHARGED BATTERIES WITH THE MFJ-269
POWER SWITCH OFF, WITH ENOUGH CHARGING TIME TO ESTABLISH
FULL BATTERY CHARGE (AT LEAST TEN HOURS). NEVER CHANGE
BATTERIES WITH THE POWER SWITCH ON, OR WITH AN EXTERNAL
SUPPLY PLUGGED INTO THE MFJ-269.
The internal charger trickle can be used to charge internal batteries. The charger functions any time proper
external voltage is applied, even when the MFJ-269 is turned off. Proper charger operation requires an external
supply operating between 14 to 18 volts. Whenever the external supply is operating between 14-18 volts, the
internal trickle charging circuit will operate correctly. Typical battery charging current is 10-20 mA through the
internal charging system. The MFJ-1315 supply fulfills all power supply requirements. Batteries should be
removed before shipping this unit.
When using rechargeable batteries, the internal black plastic jumper located inside the cover (near the external
power jack on the circuit board) must be set to the proper position. If it is not set to the proper position, the
batteries will not charge. With rechargeable batteries, the internal charger jumper located on the printed circuit
board near the power jack should be set like this:
2.4 Using Conventional “AA” Drycell
Batteries
If possible, use good quality alkaline batteries. Conventional
batteries can be used with the MFJ-269, but high quality alkaline batteries offer slightly less risk of battery
leakage generally provide longer service and shelf life.
Charger is now ON