Keyer Magic by John W. Cartinhour, Jr., N5DY

Below is the schematic for the Keyer Magic Electronic Keyer that was published in the October 1981 issue of 73 Magazine written by John W. Cartinhour, Jr., N5DY. While the key front end (Page 1) is pretty straight forward, the dot/dash decision section (Page 2) is pretty unique.

I was going to include all of the text and other drawings from the original article. But John was so detailed that you are better off reading the original article yourself.

Schematic, Page 1
8
7
6
5
4
3
2
1
8
7
6
5
4
3
2
1
A
B
C
D
A
B
C
D
John W. Cartinhour, Jr., N5DY
Title
Keyer Section
Size
B
Document Number
73 Mag, Oct 1981
Rev
None
Date:
3/7/2020
Sheet 1 of 4
DOT
PADDLE
R1
10KΩ
+5V
3
4
SN7404
U4
A
9
8
SN7404
U4
C
A
S2-B3
A
S2-C4
10
9
8
SN7400
U1
A
1
2
3
SN7400
U2
A
4
5
6
SN7400
U2
B
X
S2-B3
DASH
PADDLE
R2
10KΩ
+5V
5
6
SN7404
U4
B
10
9
8
SN7400
U2
C
Y
S2-B2
13
12
11
SN7400
U2
D
4
5
6
SN7400
U1
B
B
S2-A5
8
9
10
SN7402
U3
A
5
6
4
SN7402
U3
B
2
3
1
SN7402
U12
A
DOT_NBM
S2-C8
DASH_NBM
S2-C8
5
6
4
SN7402
U12
C
11
12
13
SN7402
U12
D
DIS
RST
THR
OUT
TRI
CTL
7
6
2
4
3
5
U10
NE555
+5V
DIS
RST
THR
OUT
TRI
CTL
7
6
2
4
3
5
U11
NE555
+5V
CLK
S2-D1
R3
10KΩ
+5V
R4
15KΩ
+
C1
1uF
D1
1N4148
C2
0.01 uF
R5
10KΩ
+5V
R6
15KΩ
+
C3
1uF
C4
0.01 uF
SPEED
R7
5K
+
5
V
8
9
10
SN7402
U12
B
UNUSED LOGIC
13
12
11
SN7400
U1
D
11
10
SN7404
U4
F
S
R
J
K
Q
Q
6
9
12
7
8
11
10
SN7476
U5
B
Schematic, Page 2
8
7
6
5
4
3
2
1
8
7
6
5
4
3
2
1
A
B
C
D
A
B
C
D
John W. Cartinhour, Jr., N5DY
Title
Dot/Dash Gen./ Mem. and Decision
Size
B
Document Number
73 Mag, Oct 1981
Rev
None
Date:
3/7/2020
Sheet 2 of 4
13
12
SN7404
U4
D
CLK
S1-C1
S
R
J
K
Q
Q
1
4
16
2
3
15
14
SN7476
U5
A
R8
1KΩ
+
5
V
DOT_NBM
S1-C5
S
R
J
K
Q
Q
1
4
16
2
3
15
14
SN7476
U6
A
DASH_NBM
S1-B5
S
R
J
K
Q
Q
6
9
12
7
8
11
10
SN7476
U6
B
S
R
↑
D
Q
Q
3
2
4
1
5
6
SN7474
U7
A
S
R
↑
D
Q
Q
11
12
10
13
9
8
SN7474
U7
B
1
2
3
SN7400
U1
C
2
3
1
SN7402
U3
C
1
2
SN7404
U4
E
CW_OUT
S3-C6
R10
2.2KΩ
+5V
D0
D1
D2
D3
D4
D5
D6
D7
A
B
C
G
Y
W
4
3
2
1
15
14
13
12
11
10
9
7
5
6
SN74151
U8
X
S1-C7
B
S1-A6
A
S1-D6
A
S1-D6
D0
D1
D2
D3
D4
D5
D6
D7
A
B
C
G
Y
W
4
3
2
1
15
14
13
12
11
10
9
7
5
6
SN74151
U9
Y
S1-B7
R9
1KΩ
+
5
V
Schematic, Page 3
8
7
6
5
4
3
2
1
8
7
6
5
4
3
2
1
A
B
C
D
A
B
C
D
John W. Cartinhour, Jr., N5DY
Title
Sidetone and Output Keying
Size
B
Document Number
73 Mag, Oct 1981
Rev
None
Date:
3/7/2020
Sheet 3 of 4
CW_OUT
S2-C1
R11
10KΩ
Q1
ECG123A
R12
4.7KΩ
R13
1KΩ
Q2
ECG159
+5V
L1
RFC
S1
TUNE
TO TRANSMITTER
KEYING JACK
(GRID BLOCK KEYING)
DIS
RST
THR
OUT
TRI
CTL
7
6
2
4
3
5
U13
NE555
R14
10KΩ
+
5
V
R15
50KΩ
C5
0.01uF
C6
0.01 uF
+
C7
15 uF
R16
220Ω
SP1
8Ω
+
-
S2
ON/OFF
Schematic, Page 4
8
7
6
5
4
3
2
1
8
7
6
5
4
3
2
1
A
B
C
D
A
B
C
D
John W. Cartinhour, Jr., N5DY
Title
Power/Ground
Size
B
Document Number
73 Mag, Oct 1981
Rev
None
Date:
3/7/2020
Sheet 4 of 4
+5V DC
Ground
+5 Volt
Power
+
C3
33 uF
VCC
GND
14
7
U1 - SN7400
C8
0.01uF
VCC
GND
14
7
U2 - SN7400
C9
0.01uF
VCC
GND
14
7
U3 - SN7402
C10
0.01uF
VCC
GND
14
7
U4 - SN7404
C11
0.01uF
VCC
GND
5
13
U5 - SN7476
C12
0.01uF
VCC
GND
5
13
U6 - SN7476
C13
0.01uF
VCC
GND
14
7
U7 - SN7474
C14
0.01uF
VCC
GND
16
8
U8 - SN74151
C15
0.01uF
VCC
GND
16
8
U9 - SN74151
C16
0.01uF
VCC
GND
8
1
U10 - NE555
C17
0.01uF
VCC
GND
8
1
U11 - NE555
C18
0.01uF
VCC
GND
14
7
U12 - SN7402
C19
0.01uF
VCC
GND
8
1
U13 - NE555
C20
0.01uF
+5V