Commodore 1571 - Page 40

1571/C128D ALIGNMENT/REPAIR TEST
VERSION 1.2.1
CHECK FOR ALTERNATING DATA LINES --- INPUT HEX CODE 'AA'
NOTE: HEX 'AA' DATA LOOKS EXACTLY THE SAME AS HEX '55' DATA
X X J. X
DATA BUS 1 CHECK IC
DISPLAY | PINS
EXPECTED
SIGNAL
SCOPE 1 INCORRECT SIGNAL
MODE 1 PROBABLE FAILURE
10101010
10101010
10101010
10101010
10101010
10101010
U4 - 2,4,6,8
U4 - 3,5,7,9
U6 - 37,38
U7 - 9,10
U7 - 6
U7 - 8
LOW
HIGH
SERIAL DATA
SERIAL DATA
ANALOG DATA
ANALOG DATA
DC
DC
DC
DC
AC
AC
U4 - U6
U4 - U6
U6 - U14
U14 - U7
U7 - CR3 - CR4
BAD DRIVE
U7 - CR7 - CR8
BAD DRIVE
CHECK FOR DOUBLING DATA LINES
--- INPUT HEX CODE '66'
NOTE: HEX '66' DATA IS DIRECTLY INVERSE TO HEX '99' DATA
DATA BUS 1 CHECK IC
DISPLAY | PINS
EXPECTED
SIGNAL
SCOPE
MODE
INCORRECT SIGNAL
PROBABLE FAILURE
01100110
01100110
01100110
01100110
01100110
01100110
U4 - 2,5,6,9
U4 - 3,4,7,8
U6 - 37,38
U7 - 9,10
U7 - 6
U7 - 8
LOW
HIGH
SERIAL DATA
SERIAL DATA
ANALOG DATA
ANALOG DATA
DC
DC
DC
DC
AC
AC
U4 - U6
U4 - U6
U6 - U14
U14 - U7
U7 - CR3 - CR4
BAD DRIVE
U7 - CR7 - CR8
BAD DRIVE
CHECK FOR DOUBLING DATA LINES
--- INPUT HEX CODE '99'
NOTE: HEX '99' DATA IS DIRECTLY INVERSE TO HEX '66' DATA
X X X X
DATA BUS
DISPLAY
CHECK IC
PINS
EXPECTED
SIGNAL
SCOPE 1 INCORRECT SIGNAL
MODE | PROBABLE FAILURE
10011001
10011001
10011001
10011001
10011001
10011001
U4 - 2,5,6,9
U4 - 3,4,7,8
U6 - 37,38
U7 - 9,10
U7 - 6
U7 - 8
HIGH
LOW
SERIAL DATA
SERIAL DATA
ANALOG DATA
ANALOG DATA
DC
DC
DC
DC
AC
AC
U4 - U6
U4 - U6
U6 - U14
U14 - U7
U7 - CR3 - CR4
BAD DRIVE
U7 - CR7 - CR8
BAD DRIVE
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