Tektronix 321A Instruction Manual page 10

Preliminary Instructions- Type 321 A
De Operation
Operation from on external de source is ocompli1hed by
connecting the special pigtail-type de power cord in the
proper manner. For
11.5-
to 20-volt operation, the block
1+1
and white
1-)
leads ore connected to the voltage
source; for
20-
to 35-volr operation, the green
1+1
and white
1-·)
leads ore connected to 1hc voltage source. When the
connections to the external de voltage source arc properly
mode, the external de source is floating with respect to the
Type
321A
chassis. Up to 600 volts difference is permissi-
ble, if necessary.
To turn on the Type
321
A, set the POWER switch to EXT
ON. To turn off the oscilloscope, set the POWER switch to
one of the OFF positions- TRICKLE or
FULL.
When operating from the external de source, the ac line
cord should be disconnected. That is, only one of the exter-
nal sources should be used rather than both at the some time.
2-4
N OTE
The internal battery charger circuit is d isconnected
during external d e operation . Therefore, external
batteries ( if used a s the de source l cannot be
cha rged by connecting the line cord to the oc line.
Also, on ex ternal de source cannot be used to
cha rge the internal batteries since the POWER
switch does not electrically connect the twa
sources together.
LOW BATTERIES Ught
The LOW BATTERIES light turns on when the following
conditions exist:
1.
Tho POWER switch is set to BATI ON and the internal
batteries drop to 11.5 v (:!.:.0.2 v) or lower.
2. The POWER switch is set to
EXT
ON and the external
source voltage is low enough to ca use the Type
321A
un-
regulated voltage to drop to about
11.5
v or lower.