Repair Procedure 01 - NCR PC4i Service Manual

C
LEVEL 1 DIAGNOSTICS ERROR RETURNS
Detail code:
01 Parity error interrupt
02
Base RAM parity error
04 Expansion RAM error
These codes are logically "or"ed to present the
final detail code.
Example:
03
or: 04
Parity error
&
interrupt from the
base RAM
Parity detected from expansion
RAM with no interrupt.
Repair Procedure 01
The detail code will give the location of a parity
failure (base or extended memory). Use the most
significant digit of the segment code to identify
whj_ch bank contains the defective RAM IC. This can be
done by using Figure 5-5, Refer also to Figures 5-3
and 5-4 shown earlier in this chapter.
Locate the segment number in the table and find the
data bit(s) that failed the RAM PATTERN TEST. The
junction of the row and column will intersect the IC
that is suspect, The locations of the ICs are found
on both MPBs, the Alternate and Early-Type MPB, all
other RAMs are located on the Memory Expander Card.
Memory bit IC locations on the MPB are shown in
Figure 5-8 and Figure 5-9, respectively. If the
test indicates a parity failure and the RAM PATTERN
TEST passes, then suspect the parity IC within the
faulty segment.
5-13