Commodore 1571 - Page 36

1571/C128D ALIGNMENT/REPAIR TEST
VERSION 1.2.1
*****
C128D STEPPER MOTOR CONTROL LOGIC
INCORRECT STP 0 OR STP 1 SIGNALS
-- ADVANCED CHART 1
FROM BASIC CHART 1
*****
STP 0
DISPLAY
STP 1
DISPLAY
CHECK
PINS
IC EXPECTED
SIGNAL
INCORRECT SIGNAL
PROBABLE FAILORE
0 0
U104
_
10
0
VDC 0104
—
0111
0
0
0104
—
11 0
VDC 0104
-
0113 - 0111
0 0
Ulll
—
8
0 VDC Dili
-
O110
0
0
0110
-
5 0 VDC
0110
-
0109
0 0
0110
-
12
+5 VDC
olio
-
0109
0
0
0113
—
12
+5
VDC
0113
-
0109
0
0
0113
-
10
0
VDC
0113
-
0109
0 0
0109
-
12,14
+5 VDC 0109
—
BAD DRIVE
0 0
0109
-
13,15 +1
VDC 0109
-
BAD DRIVE
0 1
0104
10
0 VDC
0104
_
0111
0 1
0104
-
11
+5 VDC 0104
—
0113 - 0111
0
1
0111
-
8
+5 VDC 0111
-
O110
0
1
0110
-
5 +5
VDC O H O
—
0109
0 1
0110
-
12
0
VDC
O H O
—
0109
0 1
0113
—
12
0 VDC
0113
-
0109
0 1
0113
-
10
+5 VDC
0113
-
0109
0
1
0109
-
12,14
+1 VDC 0109
-
BAD DRIVE
0 1
0109
-
13,15 +5 VDC
0109
-
BAD DRIVE
1
0
0104
—
10
+5
VDC
0104
_
0111
1
0
0104
-
11
0 VDC
0104
-
0113 - 0111
1
0
0111
-
8
+5
VDC
0111
-
O H O
1 0
O H O
-
5
+5
VDC O H O
—
0109
1
0
0110
-
12
0
VDC
0110
-
0109
1
0
0113
-
12
+5
VDC
0113
-
0109
1
0
0113
-
10
0 VDC
0113
-
0109
1
0
0109
—
12,15
+1 VDC
0109
-
BAD DRIVE
1
0
0109
-
13,14
+5 VDC
0109
-
BAD DRIVE
1
1
0104
—
10
+5 VDC
0104
_
0111
1
1
0104
-
11
+5 VDC
0104
-
0113 - 0111
1 1
0111
—
8
0 VDC 0111
-
0110
1 1
0110
—
5 0 VDC
olio
-
0109
1 1
0110
—
12
+5 VDC
O110
-
0109
1 1
0113
—
12
0
VDC
0113
-
0109
1
1
0113
-
10
+5
VDC
0113
-
0109
1
1
0109
-
12,14
+5 VDC
0109
-
BAD DRIVE
1
1
0109
-
13,15 +1
VDC
0109
-
BAD DRIVE
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