I have a Dahua NVR5208-8P-4KS2E which does not appear to be booting. It was working fine until I powered it down remotely, and then I could not get it to come back up. The unit usually comes back up with a status beep and reconnects to my network. Instead, it appears that the case fan is ramping up in speed for 35 seconds, slowing down for 9 seconds, and ramping up 35 sec. It repeats this cycle constantly with no video output to an attached monitor and is not connecting to the network. I disconnected the hard drive and attempted to boot with the same result. The only front panel light coming on is the blue power light. The HDD light and status light are not coming on. There are two steady LEDs which light on the motherboard (red and amber). I attempted to remove the onboard lithium battery and reboot with no success. Can anyone help me?