Power Supply Board; Ac Power; Dc Power - Printronix P5000 Maintenance Manual

AC Power

The printer has five electric motors: two ribbon drive, one paper feed, one
platen open, and one shuttle motor. The shuttle motor is a brushless DC
motor driven by current control. The MPU encoder is used as feedback for
motor commutations, hammer fire timing, and motor stall detection. The paper
feed motor is a DC stepping motor driven by current control. The paper feed
motor may be driven in full, half, or microsteps, depending on print
requirements. The ribbon system uses two DC stepping motors that alternate
drive and drag roles when the ribbon reaches turnaround. The drive ribbon
motor is microstepped in voltage mode, while the drag motor is loaded and
monitored to maintain correct linear speed and tension. The platen motor is
driven in current mode and can be full or half stepped. The overall current
level may be reduced for standby modes.
The paper feed, ribbon drive, and shuttle motors are driven in control loops
containing power MOSFETs, voltage and current sensors, the MECA ASIC,
and the EC processor. The platen motor is driven by a stepping motor
controller IC and the EC processor.
Control of the hammer drive is split between the controller board and the
hammer bank. Common circuits are located on the controller board, while
circuitry specific to the hammers is contained on the hammer bank. The EC
uses the MECA ASIC on the controller board to set timing and upper drive
profiles for hammer fire events. The controller also contains diagnostic
circuitry for the hammer system. The hammer bank contains HBA ASICs that
interpret fire commands and data from the MECA and VX ASICs. The HBAs
control lower drive MOSFETs on the hammer bank. These determine which
hammers will participate in a fire event generated by the controller's upper
drive.

Power Supply Board

The printer power supply is contained on a printed circuit board mounted on
the rear wall of the card cage. The power supply automatically senses and
adjusts to any commercial electrical system that provides AC mains potential
in 50 or 60 Hertz systems. This means the printer can operate anywhere in
the world on local commercial power.
The power supply converts alternating current (AC) to direct current (DC) at
three voltage levels and sends the DC voltages to the controller board. The
controller board distributes all DC power to the logic and electromechanical
circuits.
AC Power
The power supply operates on AC voltages ranging from 88 volts to 270 volts.
It can tolerate variations in frequency of 47 to 63 Hz. The power supply is
designed to withstand an AC input overvoltage of 300 VAC for one second
with no degradation of DC output voltage or damage to printer circuits.

DC Power

The power supply board contains two DC power supply systems for the
printer. The first is a +5 V bus for logic. The second consists of +48 V and
+8.5 V buses for the hammer bank and all motors.
269