Genicom 3600 User Manual

A media supply assist roller and brake assembly are part of the media supply
post function. The free spinning roller reduces the drag of the media core over
the stationary supply post, allowing the media to turn smoothly during
printing. When printing stops, the media slackens under the upper media
guide, causing the media brake pedal and brake arm to lower onto the rubber
contact strip on the brake drum, which inhibits media roll momentum by
stopping the assist roller.

This section describes the basic electronic functionality of the 3600 printer.
Components are identified by the reference designators used on the schematic
diagrams (provided in Chapter 6).

The power supply for the 3600 is primarily a linear supply with a switching
buck converter for the 24V printhead supply. The switching buck converter
takes the unregulated +50V and uses a switching transistor to reduce the
output voltage to +24V. The base mechanism is equipped with an AC input
filter and a transformer that supplies the board 12 VAC and 50 VAC.

The +5V supply is generated from the 12 VAC inputs on connector J10. Diode
bridge D12 rectifies the AC voltage and regulator VR1 regulates the DC voltage
to +5V. Capacitors C53 through C56 are used for filtering and storing energy
for hold time at power down or blackout. VR1 is rated at 1.5A and is
sufficiently heatsinked to handle this amount of current. The typical +5V load
is approximately 1A.

The +40V supply is generated from the 40 VAC inputs on connector J10. Diode
bridge D13 rectifies the AC voltage capacitors C95 and C58 that are used as
filters. 40 VAC is unregulated and used for the stepper motor voltage. The
+40V supply is also zenered down to 5.1V to supply the motor logic. This
prevents excessive motor currents on power up. Another zener diode is used to
supply 15V that is used by the +24V buck converter.

The +24V supply is generated by a switching buck converter.