Canon A-200 series Service Manual page 136

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RAM failure except the system RAM area
The read data and written data dont match in the address 10000-3FFFF and 40000-7FFFF. The
patterns of data are
''AA,
55, 00 and FF':
XX denotes the segment address where the error has occurred and YY is the actual data read
from the RAM.
*
If the error bit is only one bit such as "01" or "FE': replace the RAM chip in accordance with
the following table.
08 or 09 or 010 or 011 or 012 or 013 or 014 or 015 or
Bit
Parity
Segment
DO 01
02 03 04 05
06 07
~
OO-OF Not checked in this test
!ll
U36 or U31 or U26 or U22 or U18 or U13 or U9 or U5 or U1 or
10-1 F
0
a..
U37
U32 U27 U23 U19 U14 U10
U6 U2
c
·co
U38 or U33 or U28 or U24 or U20 or U15 or U11 or U7 or
U3 or
20-3F
~
U39 U34 U29 U25 U21 U16 U12 U8
U4
*-0
U2 or U3 or U4 or U5 or U6 or U7 or
U8 or
U9 or U10 or
~
co 40-5F
- 0
U11 U12
U13
U14 U15
U16 U17
U18 U19
~m
.g~
U21 or U22 or U23 or U24 or U25 or U26 or U27 or U28 or U29 or
0.«
60-7F
00:
U30 U31
U32 U33 U34 U35 U36
U37 U38
*
When S1-1 and S1-5 are on.
Table 8-1
*
In other case, check the interface signals.
T2 T3
T4
CPU-ClK
AO-A7
ROW
A~DRESS
X
CO~UMN
ADDRESS
DOUT
----~--------~~(-----~~)~--------
DIN
----~--~{~----~------------)~--------
Figure 8-1
133