General; Map A20, Control Logic Failure - IBM 3274 51C Maintenance Information

Chapter 3. Maintenance Analysis Procedures
3.1 General
This chapter contains all the Maintenance Analysis Pro-
cedures (MAPs) required to support the Subsystem Problem
Isolation steps described in the preceding chapter. You
will have been directed to a specific MAP by some state-
ment or reference in the sequence. The MAPs are presented
in numerical sequence. In performing any MAP, you must
follow the procedure exactly as given. Remember to
perform Machine Check MAP AlOO after having fixed the
problem'.
3.2 Contents
MAP AlO, Bus Test 3-2
MAP A20, Control Logic Failure 3-7
MAP A40, Diskette Failure 3-11
MAP ASO, Type A Adapter Failure 3-17
MAP A90, Device Adapter Type B Failure 3-20
MAP AlOO, Machine Checkout 3-22
MAP A120, Power Problem, Ind On or Off 3-24
MAP A 122, Power On Ind Is Ofr and
Fan Not Turning 3-3.6
MAP A130, I.M. 2400,4800,9600 Failure 3-42
MAP AlSO, Installation/Customization Problems 3-47
Chapter 3. Maintenance Analysis Procedures 3-1