
Operating Instructions—Type 324
The Power Pack is normally put on charge without re
moving it from the oscilloscope. However, it can be charged
while it is outside of the oscilloscope. This permits better
air circulation around the pack, thus maintaining a cooler
battery temperature. Slightly more energy will be stored in
the cells, providing a little longer battery-operated cycle. In
addition, the ability to be charged independent of the
oscilloscope permits continuous internal battery-powered
use if a second Power Pack is obtained. Less than one
minute is required for exchanging Power Packs.
If NiCd cells become reverse charged, their capacity for
re-charging can be impaired or destroyed. The battery
charger is designed to prevent accidental application of re
verse charging current. However, an unbalance between
cells in a battery can develop during operation or during
partial charging. It is possible for the unbalance to become
so great that during discharge the weakest cells completely
lose their charge and then become reverse-charged by the
current from the strong cells.
Considering that the battery initially consists of equal-
quality cells, the way to avoid reverse-charging an individual
cell is to keep the cells equally charged. This can be done
by completing a full-charge cycle, which consists of apply
ing F U L L CHG current for 16 hours. The full charge cycle
should be completed in preference to a partial charge cycle
whenever possible. In addition, approximately once a
month or every 15 charge-discharge cycles (whichever
occurs first) the battery should be charged at a F U L L CHG
rate for approximately 24 hours.
Once the battery has been fully charged, the Power Pack
switch should be placed in T R IC K L E CHG and the AC
power cord should be left connected. This will keep the
battery in a fully charged condition.
Although partial recharging of NiCd batteries is not
recommended as a common practice, occasional partial
recharges can be tolerated. About 30 to 45 minutes of oper
ating time can be expected as a result of a one hour charge
period.
The energy-storing capability of the NiCd cells decreases
gradually with age and the number of charge-discharge
cycles. However, the battery should provide a useful oper
ating life well in excess of several hundred charge-discharge
cycles.
Storage
NiCd cells can be stored either fully or partially charged.
Storage temperature may be between —4 0 °C and +75°C ,
but the self-discharge rate increases with temperature. A t
+ 20°C , a fully charged cell can be expected to self
discharge down to about 50% in three months. Cells and
Power Packs which are not in use should therefore be given
a full re-charge at least every three months to avoid their
becoming reverse-charged.
Maintenance and Repair
Additional data regarding maintenance and repair of the
Power Pack and the NiCd cells can be found in the Mainten
ance section.
EXPLAN ATIO N OF EXTER IO R CONTROLS,
CONNECTORS AND INDICATORS
General
The following controls, connectors and indicators are
contained on, or are accessible through the exterior surfaces
of the Type 324 Oscilloscope, and are used during routine
oscilloscope operation. All other controls are inside the
covers. These controls should be moved only during instru
ment calibration. The names of all Type 324 controls, con
nectors and indicators are written in capital letters wherever
they appear in the manual. Specifications regarding the
controls can be found in Section 1.
Handle
3 2 0 ° rotation. Detents hold the
handle in any one of the numerous
positions throughout travel arc.
Detents automatically unlock in re
sponse to ro ta ry pressure on
handle.
Front Panel
POWER
T w o
p o s it io n slide sw itch.
Interrupts or completes power cir
cuit between Power Pack and re
maining oscilloscope circuitry. Does
not affect battery charging cir
cuitry.
LOW BATT
Indicator lamp. During "'battery
only" operation, flashes to indicate
that batteries must be recharged be
fore operation is continued. If the
batteries become sufficiently low,
the oscilloscope will stop operating
and the lamp will stop flashing.
Leaving the POWER switch ON
after the batteries have reached this
low state may damage the recharge
able cells. To distinguish this condi
tion from equipment failure, apply
AC power for a few minutes with
the Power Pack switch at FULL
C H G . Then disconnect the AC
power and check for oscilloscope
2-4