Wiring Diagram Notations - Lexmark W820 - Optra B/W Laser Printer Service Manual

Wiring Diagram Notations

The wiring diagrams presented in this manual use the following circuit notations to
describe components and signal paths within the printer.
A PLUG.
A JACK.
CONNECTION OF PIN 15 OF CONNECTORS P28
AND J28.
THE SIGNAL NAME OF A WIRE.
THE VOLTAGE MEASURED WITH THE NEGATIVE
PROBE OF THE METER ON SG.
THE VOLTAGE VALUE OF A SIGNAL
/ = The voltage goes LOW when the signal is ON.
In this case, the HEAT signal is ON, so the normal
voltage of 4.2 V dc drops to 0 V dc.
GND GROUND.
SGND SIGNAL GROUND.
PGND FRAME GROUND.
RTN RETURN.
There is continuity between SG and RTN.
Continuity between FG and SG depends on
circuit specifications.
$ $ in a signal name indicates the signal is
coming from the MCU CPU.
# # in a signal name indicates the signal is going
to the MCU CPU.
TTL TTL displayed in the HIGH level or LOW level
columns of the signal tables indicate the signal
is ECL_CMOS compatible.
#$ Interactive communication signal.
## Analog signal.
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Service Manual
4025-Finisher