IBM 80 User Manual

28
CARD SORTING MACHINE, TYPE 82
SORT MAGNET
r- ---- - - - ---,
1
---~I~~----------------~O~»~~--~
I Rl.230V DC ONLY I
I ... ' .. .. .. ... I
. v,,, 'V " ."
L ____________ J
+ 150 VOLTS TO ANODES AND SCREEN GRIDS
OF
25L6 TUBES AND ANODE OF OA4G TUBE
~~ 7 ~, '0' oo"'oc'""
CONTACT ROLL
COVER SWITCH 1
r------------,
RELAY GATE
TERM. 13
I R4.230V DC ONLY I
I I
L __ :.:.: ::'_'~:'~ __ -'
+ 150 VOLTS
o VOLTS TO
CATHODES OF
25L6 TUBES
OCTAL PLUG PINS
6&8
CONTACT ROLL
COVER SWITCH 2
RECTIFIED DC SUPPLY
APPROXIMATELY 150 VOLTS
NO LOAD FOR AC OPERATION
(APPROX. 115 VOLTS
FOR DC
OPERATION)
RELAY GATE
TERM. 14
I
---~~------~~~----------~--~~~----------------~~~----------~ o---~O~VO~L~TS~---o
- ,
APPROX. - 40 VOLTS BIAS TO
CONTROL GRIDS OF
25L6
TUBES AND CATHODE AND
START ANODE OF OA4G TUBE
INDUCED AC ACROSS
THIS SECTION OF COIL
(GROUND POTENTIAL)
Figure 24. Schematic 01 Oscillator and Rectifier
of the 12SN7 and the plus side of the DC supply
serves
to stabilize the bias circuit.
The
470,000 ohm resistor and .001 mfd. capacitor
in the oscillator circuit provide signal grid bias for
the rube.
The condition of the 25L6 oscillator tube should be
checked occasionally
by placing a voltmeter across the
4 mfd. condenser.
If this reading is below 25 volts
in a static condition, the 25L6 tube may be faulty. (See
the voltage chart and notes on wiring diagram
301701- D.)
Static Circuit Conditions (Figure 25)
Prior to the time that a hole is sensed by the card
brush, both ends of the
10,000 ohm resistor will be at
-40 to -45 volts, as will the control grids of the
25L6 power tubes and the cathode of the
OA4G tube
(principle
3). The starter anode of the OA4G will
also be at
-40 to -45 volts through the 47,000 ohm
and the
470,000 ohm resistors connected to one end
of the
10,000 ohm resistor and the bias supply. This
is a static condition and no current will be flowing in
the bias network. Neither will
any current be flowing
through the 25L6 power rubes to the sort magnet as
these tubes are biased beyond cutoff at this time (prin-
ciples 6 and
7). The rectified supply voltage will be
approximately
150 volts DC because the power supply
capacitor tends
to charge to peak line voltage under
light loads.
Because no current is flowing through the 25L6
power tubes, both the anodes and the screen grids of
these tubes will be at the maximum positive potential
of
150 volts (card lever contacts closed). The anode
of the
OA4G tube will also be at 150 volts positive
brushes on the commutator are electrically connected,
potential through R2 when the center and outer
but before a hole
is sensed in the card.

IBM 80 Specifications

General

Brand	IBM
Model	80
Category	Office Equipment
Language	English