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8.0.0 Power Supplies
Note:
Maintenance information for the high fre-
quency and trilevel power supplies is given in para-
graphs 8.1.0 through 8.1.12; maintenance infor-
mation for the ferro-resonant power supply is
given in paragraphs 8.2.0 through 8.2.12. To
determine which power supplies your machine
has, compare your power supply with the drawings
on Appendix page C-l.
8.1.0 HIGH FREQUENCY AND
TRILEVEL POWER SUPPLIES
DANGER
With the mainline switch on: Control volt-
ages are present at the power sequence card,
the ac board, the multilevel supply, the dual
level supply or trilevel supply, and the CE
control panel.
When the power switch on the operator control
panel is turned on:
1. Approximately 300 Vdc unreferenced is
on the ac board, the multilevel supply,
and the dual level or trilevel supply.
2. AC line voltage is present at the disk drive,
33FD, the fans, ACTB1, and the trilevel
supply.
3. DC voltages from the power supplies to
the logic gate and printer are present.
8. 1. 1
Introduction
All power supplies for the system are located at
the back right side of the machine. AC power
enters the system at the primary power area,
which contains the mainline switch, two fuses,
and a line filter. The mainline switch controls all
power to the system.
When the mainline switch is on, the sequence
control voltages of +24 Vdc, -24 Vdc, +5 Vdc,
+6 Vdc, and -6 Vdc are present. These volt-
ages originate on the ac board. Further power
sequencing and distribution is controlled by
the power switch on the operator control
panel.
The ac board distributes ac power and sequence
voltage, and contains the motor relays for
the system.
The multilevel power supply provides the
+12 Vdc, -12 Vdc, +8.5 Vdc, +6 Vdc, +5 Vdc,
-5 Vdc, and -4 Vdc.
Either a dual level or a trilevel power supply
is installed. The dual level power supply pro-
vides the +24 Vdc and -24 Vdc, when a belt
printer is installed. The trilevel power supply
provides the +24 Vdc, -24 Vdc, and 48 Vac
when a serial printer is installed.
Multilevel Power Supply
Main
ril-;
Line~)2QJ
Switch
101 102
'\./
Fuses
Dual
Level
Transformer*
/
Ferro-
Capacitor
Lightning
Arrester
~
Line Filter
I
*285 Ipm printer only.
The power sequence card provides both power
sequence control and power fault retention
capabilities. The source and reason for
dropping power is retained in a set of
latches on the sequence card and can be
displayed by the CE (7.2.13).
AC Board
Fan
Dual Level
Power Supply
(belt printer)
or
Trilevel
Power Supply
(serial' printer)
Power
Sequence
Card
I
Power Supplies
8-1
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