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YORK INTERNATIONAL94
POWER SUPPLY
(REFER TO FIG 47)
The Power Supply provides the DC power for the LCD
Display and all the printed circuit boards in the Control
Center. It receives a 100 to 250VAC input from an
external power source and provides the following DC
outputs:
• +12VDC
• +5VDC
• Ground
The +12VDC, Gnd and +5VDC outputs are applied to
the Microboard. There, these voltages are applied to
the circuits requiring the respective voltage. From the
Microboard, the +12VDC and +5VDC are distributed
to other system components requiring these voltages.
These include the MicroGateway, LCD Display and
Display Backlight Inverter Board.
As shown in Fig. 47, the Microboard contains two
voltage regulators that create separate +5VDC and
+3.3VDC supplies. The +5VDC supply is dedicated
to all the Microboard Analog circuits and is labeled
as the +5VDC (Analog) supply. It is also routed to
all Temperature Thermistors. This permits all Analog
circuits to be powered by the same supply, eliminating
any offsets caused by voltage regulator drift. The
+3.3VDC supply is utilized by the Microprocessor,
Flash Memory Card and other digital circuits. It
could also be applied to the Backlight Inverter Board,
depending on the Display manufacturer’s requirements
as explained next.
Different Display manufacturers can require different
supply voltages for their display and supporting circuits.
To accommodate the different Display manufacturer’s
voltage requirements, Microboard Program Jumpers JP2
and JP5 must be positioned to provide the required supply
voltages to the Display and the Display Backlight Inverter
Board. Either +5VDC or +3.3VDC, as determined
by JP2, is applied to the Display. Either +12VDC or
+5VDC, as determined by JP5, is applied to the Display
Backlight Inverter Board. Refer to Table 2 “Microboard
Program Jumpers”.
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