Seasonic Prime Ultra Platinum 550 Always looking at connector side, lock on the right.
Pin 1, 2 and 3 are defined on the connector by stripes on the side.
24-pin motherboard connector
Color
Signal
Pin
Pin
Signal
Color
Orange
+3.3V
1
13
+3.3V
Orange
Orange
+3.3V
2
14
−12V
Blue
Black
GND
3
15
GND
Black
Red
+5V
4
16
Pwr ON
Green
Black
GND
5
17
GND
Black
Red
+5V
6
18
GND
Black
Black
GND
7
19
GND
Black
Grey
Pwr OK
8
20
NC
None
Purple
+5V SB
9
21
+5V
Red
Yellow
+12V
10
22
+5V
Red
Yellow
+12V
11
23
+5V
Red
Orange
+3.3V
12
24
GND
Black
There's two cables on the other side
18 pin atx connector
10 pin atx connector
Signal
ATX Pin
Pin
Pin
ATX Pin
Signal
+5V
6
1
10
22
+5V
+5V
21
2
11
4
+5V
+5V
23
3
12
6
+5V S
GND
3
4
13
17
GND
GND
7
5
14
5
GND
GND S
3
6
15
15
GND
NC
---
7
16
2
+3.3V S
+3.3V
12
8
17
13
+3.3V
+3.3V
2
9
18
1
+3.3V
Signal
ATX Pin
Pin
Pin
ATX Pin
Signal
GND
24
1
6
10
+12V
GND
19
2
7
11
+12V
GND
18
3
8
14
-12V
+12V S
10
4
9
9
+5V SB
Pwr ON
16
5
10
8
Pwr OK
Color
Signal
Pin
Pin
Signal
Color
Black
GND
1
5
+12V
Yellow
Black
GND
2
6
+12V
Yellow
Black
GND
3
7
+12V
Yellow
Black
GND
4
8
+12V
Yellow
Signal
ATX Pin
Pin
Pin
ATX Pin
Signal
+12V
8
1
5
1
GND
+12V
7
2
6
2
GND
+12V
6
3
7
3
GND
+12V
5
4
8
4
GND
Color
Signal
Pin
Pin
Signal
Color
Yellow
+12V
1
5
GND
Black
Yellow
+12V
2
6
GND
Black
Yellow
+12V
3
7
GND
Black
Black
GND
4
8
GND
Black
Signal
ATX Pin
Pin
Pin
ATX Pin
Signal
+12V
3
1
5
8
GND
+12V
2
2
6
7
GND
+12V
1
3
7
6
GND
+12V
---
4
8
4,5
GND
