Data General NOVA 4/S Manual page 39

This chapter will help you find the failing field
replaceable units in the power supply and power
distribution system. When you find a failing unit,
replace it following the replacement procedure given in
Chapter 14. For a detailed description of how the power
supply operates, see Chapter 9 (16-slot) or Chapter 10
Before you try to troubleshoot the power supply, it is
helpful to know what the power supply does and how
27
(power fail, power ok, etc.)