Why Is My TV Remote's IR LED Always On?

[cepheid]

[SOLVED] Broken TV Remote?

My TV remote stopped working. Yes, I changed the batteries. Wondering what was going on, and staring at the infrared LED on the front of it, it suddenly occurred to me that my MacBook's built in camera is able to see infrared light (Apple even has a tip that you should point your Apple remote at your laptop's camera to see if it is still working or needs to have its batteries changed).

So I pointed the TV remote at the camera and much to my surprise, the remote's IR LED is active *all the time*, and it's pulsing (at very low frequency...low enough that I can see it). It pulses like that unless if I press a button on the remote, in which case it turns off and stays off as long as I hold the button down.

That seems backwards to me. I thought that the LED was supposed to stay off until a button on the remote control is pressed, at which point a binary signal is sent to the LED and it will emit a (fairly high frequency) pulsed signal of IR that varies depending on what command you are issuing (what button you're pressing).

Does this mean for sure that the electronics in my remote are messed up? (The LED being on when it's not supposed to be would explain why I observed that the TV's volume appear to change by itself shortly before the remote went on the fritz).

 

[DaveC426913]

So, it's on when no buttons are pressed, and off when buttons are pressed.

It's all backwardsed.

Take the batteries out and put them in the other way.

 

[cepheid]

Surely you are joking...?

I have put them in with the polarity specified by the diagram engraved in the plastic.

Also, giving the integrated circuit -Vcc when it is expecting Vcc is not going to help.

I was pretty sure you were joking. I was just thinking out loud.

 

[turbo]

The "buttons" in the remote are likely played out and one of them is engaged all the time, overriding the other functions. Go get a $5 generic replacement and life will be good.

 

[cepheid]

Yeah, in that case it's the volume lowering button (consistent with all my observations). Damn. Yeah, I thought buying a replacement was going to be a problem, because none of the ones I saw in the dollar store today seemed to support my TV brand. But the website of the TV manufacturer has a list of codes for this model of TV and which common brands of universal remote they'll work with.

 

[DaveC426913]

Surely you are joking...?

Too deadpan?

 

[esbo]

It may have got some water in it.
Split it open and dry membrane particularly on the volume button that should cure it.
Also you could put a non conducting material on that button or what ever, then all the other
buttons would work (bar voloume).
Sounds fixable to me. Hard bit is opening the unit.