Power Supply; Beeper And Fans - ENCAD CADJET Service Manual

CadJet 3D Service Manual

Power Supply

An internal UL recognized switching power module supplies power for
the printers. It provides a constant 24VDC output from input voltage in
the 90-132 VAC and 180-246 VAC ranges. A power switch turns the
power on and off. The 24VDC is applied to the MPCB where it is
further regulated and separated into 24VDC, 13VDC, and 5VDC. The
24V supply is used for: the stepper controller (which advances the
paper); the servo controller (which moves the Carriage); and power to
fire the inkjets. The 5V supply powers the logic circuits.
The power supply is fused using a 6.3A 250V fast blow type fuse.
The outputs share a common ground which is isolated from earth
ground with in the supply itself. Earth ground and DC ground are
connected external of the power supply.
The power supply will shut down under overload/short circuit conditions
on any output over the full range of input voltage. Overvoltage protec-
tion is 20%-30% above nominal for the 24V output.

Beeper and Fans

The beeper contains built-in driver circuitry so that it beeps under
firmware control. The beeper alerts the user to error conditions.
There exists two types of fans that are on the printers.
A single fan, located behind the power supply, is used for cooling the
power supply. Air blows over the power supply and the heated air is
forced out the back of the printer.
A fan is located inside the platen with its fan vent seen from under the
platen on the right side of the printer. This fan provides suction on the
platen bed and holds the paper (media) flat during the printing process.
2-16 Theory of Operation