Memory Board Slots - HP 400 Series Servicing Manual

Identifying Defective Memory Boards
You must know the memory configuration rules for Series 400 systems before you
try to identify a failed memory board. The following list explains these rules (refer to
Figure 4-12 as you read the list):
• Memory boards must be installed in like pairs. Each board pair forms a block
of memory.
• Memory board slots on the CPU board are numbered 0A, 0B, 1A, 1B, 2A, 2B,
3A, and 3B.
• Memory boards must be installed in consecutive slots (beginning with slot 0A)
with no empty slots between boards.
• In systems that contain different sized memory boards, the largest memory
boards precede the smaller boards in the board slots. For example, if a sys-
tem's memory configuration consists of four 4-MB boards and two 2-MB
boards, the 4-MB boards reside in slots 0A through 1B, and the 2-MB boards
reside in slots 2A and 2B.
Figure 4-12. Memory Board Slots
To identify a defective memory board, perform the following steps:
1. Identify the size of the memory board in each memory slot.
2. Note the Megabyte of memory that Self Test reports on the display screen.
3. Count the Megabytes of memory in the system, beginning at Slot 0A, until you
reach the slot where the Megabyte of memory is located.
Fault Isolation 4-23