What could be causing this stereo problem?

We have a Denon AVR-1601 receiver, hooked up to our TV and everything (satellite receiver/VCR/DVD player). A few weeks ago we left the house for a short time, and left the TV/receiver on for the dogs because we were going to be back for a few minutes. When we came back, the volume was at full blast - we could hear it out in our driveway.

At first we thought one of the dogs or cats had touched the volume button, but the buttons on the remote are very small and the remote itself was pointing away from the receiver when we found it. We puzzled over it a few minutes, then forgot about it.

Last night it happened again when we weren’t in the TV room, we couldn’t see anything near the remote. We turned the volume down and were discussing it. We were standing in another room and my SO still had the remote in his hand (not pressing any buttons) and the volume increased again!

We could see the receiver, no animals were around it at all. Why is it doing this? It is still under warranty so we can take it in, but I thought I would ask here first in case there might be a logical explanation for it - would my wireless computer network be interfering at all?

It could be extraneous IR signals from some other IR wireless device in your house. Put a piece of duct tape (masking tape and black electrical tape are transparent to IR) over the remote window on the receiver and see if the problem continues. If it does, then it’s in the receiver itself.

I second Q.E.D.'s suggestion. I’ve seen IR enabled equipment respond to other remote controllers in strange ways before. I had a cable box remote control that had a habit of switching off the TV if you weren’t careful.

Ghosts!?

Partial solution – and ABSOLUTELY GUARANTEED to work part of the time – stop leaving the friggin’ TV on for the dogs. Duh. Or at least accept the incremental suffering the dogs will incur when they have to endure their entertainment with the tinny sound from the TV’s built-in speakers, rather than that provided by your receiver. (How’s THAT for kind-heartedness??)

Contrary to Q.E.D.'s comments, in my experiments, duct tape was only slightly more effective than masking or electrical tape at blocking IR signals. Also, most IR receptors in electronic equipment are recessed behind IR-transparent hunks of plastic, and trying to totally block a receptor without disassembling the equipment is an exercise in futility.

Still, Q. is probably correct in suspecting some other source of IR, possibly from another remote (Christ, there must be fifteen of 'em around this joint…) or some other source of radiation.

Thanks for all the advice. Can the remotes be sending signals even if no one is in the house? The animals have never messed with the remotes that I know of, but we do have a bunch of them (animals and remotes). A thought crossed my mind that I could have caused the volume increase last night as I was messing with the stereo in the bathroom (hooking the laptop up to it so we don’t have to listen to the crappy laptop speakers while watching DVDs in the bathtub), but the first time it happened no one was messing with the remotes. And also I was out of the bathroom - not touching the bathroom stereo remote at all - when the second volume increase happened.

It is weird, especially when the stereo remote ususally only works if pointed directly at the receiver - I have had to move around to get in the right place before, and the dogs stand in the way sometimes (between me and the receiver) and it won’t work then.

It has only happened three times so far, so it is hard to narrow down. But I will do some investigating.