01
U5
U6
U7
U8
02
U20
U21
U22
U23
04
U25
U26
U27
U28
08
U41
U42
U43
U44
10
U47
U48
U49
U50
20
U63
U64
U65
U66
40
U70
U71
U72
U73
80
U81
U82
U83
U84
00
U88
U89
U90
U91
==============================================================================
Table 5.4-2.
Defective Memory Chip Isolation Map for the COMPAQ PORTABLE 286
System Board Using 256 Kbyte RAMs (0 - 640 Kbytes)
==============================================================================
XX = 02
XX = 00
06, 08
Bank 0
Bank 1
------------------------------------------------------------------------------
Data Bit
B = 0
B = 1
B = 0
B = 1
YY or ZZ
Low
High
Low
High
------------------------------------------------------------------------------
01
U5
U6
U7
U8
02
U20
U21
U22
U23
04
U25
U26
U27
U28
08
U41
U42
U43
U44
10
U47
U48
U49
U50
20
U63
U64
U65
U66
40
U70
U71
U72
U73
80
U81
U82
U83
U84
00
U88
U89
U90
U91
==============================================================================
Table 5.4-3.
Defective Memory Chip Isolation Map for a Memory Expansion Board
Mapped into the 1 - 3 Megabyte Memory Space (256 Kbyte RAMs)
==============================================================================
XX = 10, 12,
XX = 18, 1A,
XX = 20, 22,
XX = 28, 2A,
14, 16
1C, 1E
24, 26
2C, 2E
Bank 1
Bank 2
Bank 3
Bank 4
------------------------------------------------------------------------------
Data Bit
B = 1
B = 0
B = 1
B = 0
B = 1
B = 0
B = 1
B = 0
YY or ZZ
High
Low
High
Low
High
Low
High
Low
------------------------------------------------------------------------------
80
U3
U12
U21
U30
U39
U48
U57
U66