
Echometer Company
Model – H Manual
Phone: (940) 767-4334
5001 Ditto Lane
Page 72
Fax: (940) 723-7507
Wichita Falls, Texas 76302, U.S.A.
E-Mail:
Steps to Reset and Charge a “Critically Low Battery”
In the event a Model H instrument has been without charge for a period exceeding four weeks, it
may drop to a “critically low” voltage range. When this range is reached, attempts to charge the
battery may be unsuccessful.
Please completely read through and follow these instructions carefully to insure the battery is
brought back above the critically low voltage point and will begin taking a charge.
Step 1 – Plug the Model H charger into the instrument front panel.
If the battery voltage is critically low, the light on the Model H charger will remain green.
Step 2 - In the upper right hand side of the Model H front panel, locate the pin hole next to
the microphone cable connector. Take the end of a paper clip and depress the button
inside the pin hole for three seconds.
When the paper clip is released the pinhole button, the charger indicator light will briefly (for
about one second) turn from green to red and then back to green. When the battery falls to the
critically low voltage point, the cells will trickle charge up to a point that they are able to begin
taking a charge normally. Until this point is reached, the charger light will display green.