AppleTV doesn't "Wake Up"

I just recently set up my Gen1 ATV to work with my home theater system, connected via HDMI to my Yamaha AVR's HDMI-3. The AppleTV is hard-wired via Cat6 cable to my Airport Extreme. I have dedicated a USB external drive as my "Media" drive. I use the Yamaha remote to select the active HDMI port and switch to HDMI-3. All I get is a blank screen on the TV, so I push the Menu button on the AppleTV remote. No bright flashing led to signal the wake-up. Push the upper button on the ATV remote... again, no flashing led.

So I power cycle (unplug power-wait 10 seconds-replug) the ATV and the led starts flashing, ATV splash screen comes up, ATV remote is 100% functional and all is well. That is... until the next time lapse when I switch from Cable or DirecTV back to AppleTV, and I have to pull the plug and re-plug. Kind of annoying LOL. Are there any settings within the AppleTV settings (has latest firmware/OS) to make sure the ATV listens when I beckon? I have paired the remote with the AppleTV and unpaired it from my iMac and MBP.

I'm thinking it might be some kind of LAN Wakeup issue. My iMac is on pretty much 24/7 but should I change anything in the iMac's settings since its on the network and the Media drive is connected to the iMac. Or are there LAN settings specifically for the AppleTV? Or is it possible that some settings in the Airport Extreme can be modified to resolve this problem?

Do you have the ATV set to DHCP it almost sounds like a static IP with short lease renewal.

I've been having the same problem lately.. ever since the last Software Update. I sometimes have to unplug the Apple TV to get it to come back on.