MFJ-259B Instruction Manual
HF/VHF SWR Analyzer
5
For battery replacement, batteries are accessed by removing the MFJ-259B’s small rear panel. The battery cover
is secured by 2 Phillips head screws.
2.3
Using Rechargeable “AA” Type Batteries
CAUTION: Avoid 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 charging
batteries with the MFJ-259B power switch off, with enough
charging time to establish full battery charge (at least ten
hours).
When using rechargeable batteries, an external supply that remains between 14 and 18 volts should be used.
Typical battery charging current is 10-20 mA through an internal charging system. The internal charger trickle
charges internal batteries any time a proper external voltage is applied, even when the MFJ-259B is turned off.
The MFJ-1315 supply fulfills all power supply requirements.
When using rechargeable batteries, the internal black plastic jumper located inside the cover (near the external
power jack on the back side of 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
Try to use good quality alkaline batteries. Conventional batteries will work fine, but good quality alkaline
batteries offer less risk of battery leakage and equipment damage and usually provide longer service and shelf
life.
If you use any type of non-rechargeable dry cell battery,
remove weak batteries immediately
. Batteries must be
removed before storing this unit for extended periods of time (longer than one month).
WARNING: WHEN USING CONVENTIONAL NON-RECHARGEABLE BATTERIES, THE
CHARGING SYSTEM MUST BE DEFEATED!
When using conventional non-rechargeable batteries, the internal jumper located on the back side of the printed
circuit board near the power jack
must be
set like this:
