IBM 7940 Problem Determination And Service Manual page 93

No-beep symptoms
v Follow the suggested actions in the order in which they are listed in the Action column until the problem
is solved.
v See Chapter 3, "Parts listing, Type 7940 and 7941 servers," on page 19 to determine which components
are customer replaceable units (CRU) and which components are field replaceable units (FRU).
v If an action step is preceded by "(Trained service technician only)," that step must be performed only by a
trained service technician.
No-beep symptom
No beep
No beep and the system
operates correctly
No beep and no video
(System error LED is
OFF)
No beep and no video
(System Attention LED is
ON)
Description
No beep and no video (system error
LED is off)
Possible problem with the operator
information panel.
Unknown problem
A possible system error has occurred
Action
1. Verify that ac power is present.
2. Verify that the power supply is functioning
correctly (see "Power-supply LEDs" on page
99).
3. Check to make sure that there are no failing
DIMMs in the system by removing all of the
DIMMs and then replacing them, one pair at
a time, until either the failing DIMM pair is
found or all memory fails indicating that the
system board is bad.
4. (Trained service technician only) If the
system does not become operational when
you swap out or replace the DIMMs,
replace the system board.
1. Reseat the operator information panel
cable.
2. Replace the operator information panel
assembly.
See "Solving undetermined problems" on page
121.
See "System board error LEDs and the light
path button" on page 98.
Chapter 5. Diagnostics
75