I have a M5A-99X Evo board by Asus. Recently, I found that the Power LED of the board is blinking in larger intervals (at least 1 minute dark, 1-2 seconds lit, then dark again; did not measure) even if the mains are not connected to the power supply.
The manual does not have any information on this problem. I cannot find anything in the internets, as most blinking problems refer to issues with the mains attached and usually means some overloaded bus.
Here are the datapoints I collected so far:
- The board is rather new (less than one year), but to be sure I measured the BIOS battery (CR3032 button cell), which reads 3.03 V (open circuit) or 2.1 V (with LED attached).
- There are no active (i.e. currently connected to the mains) externally powered USB devices attached.
- It seems that the blinking stops while the battery is removed.
- The system has been shut down before. No suspend-to-disk or suspend-to-ram.
Does anyone have an idea what the LED might be telling us?