Onkyo Integra A-809 input selector switching by...

Question

Hi, My Onkyo integra A-809's input selector will start randomly switching between input selections. Sometimes it does it very rapidly, and sometimes it works just fine. I'm thinking it must have to do with some interference with the infrared sensor but am not sure. I tried covering the infrared window on the front of the amp but that doesn't work. Any ideas? Should I open up the amp and try and cover or shield the sensor directly? I don't ever use the remote so it wouldn't matter if the sensor was completely blocked.