Weird fault


So. Mother-in-law has two of these boxes. One in the living room, one in the back room, each connected to a TV.

Last week, the one in the living room started doing odd things: skipping channels as though someone was sitting on a remote.

So, tried the obvious things: took the batteries out of the remote (in case the remote itself was faulty, or stuck).

No help.
Swapped the two boxes over.
The fault is in the room, somehow.
Tried to think of any mechanism where the aerial could cause this (separate aerial feeds).
I'm stumped.
update She called out an aerial guy, no fault found.
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Black Hole

May contain traces of nut
Problems reported (which apply to IR handsets in general) include:
  • Obstructed line-of-sight;
  • Interfering sources of IR, eg incandescent lamps on dimmers or fluorescent lamps (including "compact fluorescent" energy efficient lamps);
  • Other handsets accidentally transmitting.
Note that it can still be an interfering source or other handset, even when it appears that the misbehaviour only occurs when the Humax handset is in use.

See whether it still does it when covered by a towel or something. If it does, the IR receiver may well have gone "noisy".


A stuck button was my first thought, and possibly a lost handset, as it only happens in that room.
But a search of the room failed to turn up any overlooked handsets.

And taking the batteries out of the handset turned up nothing.

There's not an obvious stuck button on either handset, but they're old (could barely make out the model number) so I suppose they might have succumbed to bit-rot.

If they'd been RF remotes, I might have wondered if next door had a new telly, but IR is pretty much line-of-sight.

I've decided to replace the handset as a precaution.

I must also see if I can source an IR camera, and look for other sources of interference -

I wonder if there's an Android app for that?

Black Hole

May contain traces of nut
I must also see if I can source an IR camera, and look for other sources of interference -
Have you eliminated an internal fault yet (as per post 2)?

As for an IR camera: as per the article I quoted from, you might well have one in your pocket. Electronic image sensors are sensitive to IR (you don't need one that is exclusively IR). Some phone/tablet/webcam sensors have an IR blocking filter built in, but your typical smart phone is fitted with two cameras, and if the front camera doesn't "see" IR, the selfie camera might well. All you need to do is enable the camera function, and use the viewfinder feature to go hunting.

However, it is much easier to test whether something in particular is transmitting than go around randomly hoping to find something that is. That's why you should try covering the unit first.