[DistantSynAck]

Try plugging the RPi into another HDMI port on the TV. CEC might only work on port 1. If you are plugging into an AV receiver then that will go in HDMI 1 on the TV and the RPi should go into HDMI 1 on the AV receiver. I looked up this unit and I didn't see any mention of CEC capability but most manufactures don't mention it anymore or re-brand it. A call to the vendor of the TV might confirm that CEC is available.

I tried both HDMI ports and the menu has a CEC On/Off setting and OE said CEC device detected, so it does have some sort of CEC but it must be some weird version that doesn't work with the Pi. Apparently it's not very standardized, even amongst sets from the same manufacturer.

Try finding the CEC settings on the TV and do a device discovery. On the Pi under System, Settings, Input Devices, Peripherals, CEC Adapter check your settings and make sure it is enabled and Switch source to this device on startup is selected. If that doesn't help change the Physical Address number (overrules HDMI port).

You say this works on your TV, can you swap Pi's and verify this still works. That would rule out a config issue.

I thought CEC didn't work on my TV at first because I was hitting the wrong keys and I had to discover the device. Only buttons that work on my setup are directional pad, OK, Exit, Play, Pause, Stop, FFWD, Rewind.

I was thinking of picking up an USB IR receiver at some point so I can get all the buttons working on my Harmony650. I do have IR modules that I plugged into the GPIO ports at one point but it looks messy and hard to setup, though it was only 2 dollars as RadioShack was closing down.

Good Luck