Casella CEL CEL-393 - Manual (Page 15)

3. PREPARATION FOR USE
The CEL-393 is despatched from our works fully calibrated and tested,
hence it is only necessary to fit the battery and connect the microphone
and preamplifier in order to prepare it for service.
Before installing the battery, ensure that the weighting switch (Figure 3)
is in the POWER OFF position. The battery is located in the compartment
accessible through the cover situated in the bottom right hand corner of
the back plate of the instrument. Removing the single retaining screw
gives access, and the battery may then be located as shown in Figure
2.
Prior to pressing the battery into place, it is necessary to locate the pull
up ribbon between the contact studs to facilitate battery removal, ensur-
ing that it does not interfere with the contact arrangement.The battery
should be inserted angled base first, and then pushed home so that the
battery contacts locate against the spring contacts which also secure the
battery in place.
Special care must be taken to ensure that the battery is connected with
the correct polarity. The +ve terminal stud on the battery goes to the right
as the instrument is viewed from the rear. Once the battery is correctly
connected, the cover may be replaced to secure the cell in place.
Correct battery installation may be verified by switching the unit ON,
which will bring the
mnemonic to the display along with the battery
voltage for about 25 seconds. Battery voltage should be greater than
6.5V for correct operation of the A version, and greater than 6.8V for the
B version.
It is important that only the recommended alkaline battery types are used.
Zinc-carbon batteries are not suitable for use in these instruments.
Reference should be made to Chapter 9 of this Handbook for further
information relating to both internal and external power supplies.
393 Handbook /11.