Canon NP6251 Service Manual page 4

Chapter 11 Troubleshooting provides tables of maintenance/inspection,
standards/adjustments, and problem identification (image
fault/malfunction).
Appendix contains a general timing chart and general circuit diagrams.
The following rules apply throughout this Service Manual:
1. Each chapter contains sections explaining the purpose of specific functions and the
relationship between electrical and mechanical systems with reference to the
timing of operation.
In the diagrams,
signal name accompanies the symbol
of the electric signal.
The expression "turn on the power" means flipping on the power switch, closing the
front door, and closing the delivery unit door, which results in supplying the machine
with power.
2. In the digital circuits, '1' is used to indicate that the voltage level of a given signal
is "High," while '0' is used to indicate "Low." (The voltage value, however, differs
from circuit to circuit.)
In practically all cases, the internal mechanisms of a microprocessor cannot be
checked in the field. Therefore, the operations of the microprocessors used in the
machines are not discussed: they are explained in terms of from sensors to the
input of the DC controller PCB and from the output of the DC controller PCB to the
loads.
The descriptions in this Service Manual are subject to change without notice for
product improvement or other purposes, and major changes will be communicated in the
form of Service Information bulletins.
All service persons are expected to have a good understanding of the contents of this
Service Manual and all relevant Service Information bulletins and be able to identify and
isolate faults in the machine.
ii
COPYRIGHT © 1997 CANON INC.
represents the path of mechanical drive—where a
CANON NP6350/NP6251 REV.0 JULY 1997 PRINTED IN JAPAN (IMPRIMÉ AU JAPON)
, the arrow indicates the direction