Data General NOVA 4/S Manual page 5

Unit Manual
PREFACE
The first chapters of Part II describe procedures for
finding a failing field replaceable unit using:
e« The CPU's self-test feature
These procedures, written in a '"cookbook'' manner,
should allow the field engineer to repair most failures
in a minimum period of time.
The latter chapters contain reference information about
the operation of the major printed circuit boards, which
will be useful when troubleshooting with an
oscilloscope.
Part III provides detailed mechanical replacement
procedures for each field replaceable unit.
WARNING: The power supplies in these units have
hazardous voltages on their printed circuit boards. They
should be repaired only by trained service personnel.