User manual
DEFINITY Enterprise Communications Server Release 6
Maintenance for R6vs/si 
555-230-127  
Issue 1
August 1997
Maintenance Object Repair Procedures 
Page 10-1062PR-MEM (TN790 RISC Memory) 
10
PR-MEM (TN790 RISC Memory)
The TN790 RISC Memory contains the DEFINITY software and firmware. The 
Processor circuit pack is the most critical component in the system. 
For testing purposes, the circuit pack is logically separated into PR-MAINT, 
PROCR, and PR-MEM. This means that a memory problem requires that the 
Processor be replaced. These systems contain two types of memory: Flash ROM 
and DRAM. Flash ROM is memory that contains the boot image, part of the 
low-level maintenance firmware, PI firmware, and PACCON firmware. This type of 
memory is not erased during circuit pack resets. It can be reprogrammed via the 
upgrade software command or a Reset System 4/5 using a software memory 
card.
One section of the Flash ROM (BOOTPROM) containing the system initialization 
functions and the low-level diagnostic programs is programmed at the factory 
and is not reprogrammed by the upgrade software command. DRAM is used for 
software data storage, and it changes constantly. Both types of memory are 
present on the Processor circuit pack. The diagnostics run appropriate tests on 
both memories.
DRAM is replaceable and installed in 3 Single In-line Memory Module (SIMM) 
sockets on this circuit pack. Replacement of these SIMMs is described in "Install 
the SIMM on the TN790 Processor Circuit Pack" in Chapter 5, ‘‘
Routine 
Maintenance Procedures’’.
For all system activity, the Processor must be able to access the Memory. If the 
Processor cannot do this, the system goes into SPE-down mode. In SPE-down 
mode, fatal Memory errors may show up as Processor errors. This merely 
indicates that the Processor and the Memory are very closely linked as a matter 
of course.
If the initialization diagnostics fail, refer to the "Procedure for SPE-Down Mode" 
section in Chapter 4, ‘‘
Initialization and Recovery’’.
1. The MO is ‘‘PR-MEM’’ because all of the Memory used by the Processor is on the 
TN790 Processor circuit pack.
MO Name (in 
Alarm Log)
Alarm 
Level Initial Command to Run Full Name of MO
PR-MEM
1
MAJOR test memory a/b lo c TN790 RISC Memory
PR-MEM
1
MINOR test memory a/b sh c TN790 RISC Memory










