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3
3250/4250 Circuit Description
The instrument is comprised of the following functional blocks:
Processor
Board
Serial Port
Applications
Board
Cooling
System
Power
Supply
Head Motor
Controls
PrinterKeypadDisplay
Barcode
Port
Power Supply (Serial Suffix A - C)
The power entry assembly interfaces the AC voltage presented to the instrument with the
transformer. The transformer provides 120 VAC to the power supply board and the head
motor. The power supply provides the power to run the main printed circuit board (±12 VDC,
±5 VDC), the thermoelectrics (5 VDC), the fan (12 VDC), the stir/freeze coil (12 VDC), and the
internal printer (5 VDC).
Note The internal printer may be powered by +5 VDC (red/orange wire) or +12 VDC (violet
wire). Consult system schematics for proper service.