Please install the ATX power according to the following pin assignment:
ATX Power
12V
5V
5VSB
5V
PW-OK
-5V
GND
GND
5V
GND
GND
GND
5V
PS-ON
GND
GND
3.3V
-12V
3.3V
3.3V
12V power connector
Pin3
+12VDC
com
Pin1
P1
SY-P4VDA Quick Start Guide
Pay special care to the directionality.
Peripherals power connector
+12VDC
com
11
+12V
Pin1
GND
GND
Pin4
NC
P2