I was replacing my CPU and installed a Cooler Master Hyper 212 RGB cooler on an MSI B550-A PRO motherboard. I initially connected the cooler's RGB cable the wrong way around, so the fan spun but the lighting did not work. After shutting down the PC and flipping the connector so the arrow lined up correctly with the 12V pin on the motherboard's JRGB header, the lighting worked normally in every color and mode. Could connecting it backward have caused a short circuit or damaged the motherboard? Everything seems to be functioning normally now.
2 Answers
If the RGB lighting works normally now and the rest of the system is stable, you almost certainly did not damage the motherboard. A connector being reversed usually prevents the LEDs from receiving power correctly rather than creating a lasting short. Just make sure the arrow on the cable lines up with the +12V pin on the JRGB header before powering on.
The important distinction is that your cooler uses standard 12V RGB, which belongs on the motherboard’s 4-pin JRGB header. It should not be connected to a 5V 3-pin ARGB header. Since you corrected the plug and the lighting now responds properly, there is no obvious sign that anything was harmed. Check the motherboard manual or the header markings to confirm the voltage and pin alignment.
That was my main concern, but everything is working normally after I corrected the orientation.