Most mornings I get up and work out in my "workout" room where I have an older (circa 2000?) LG plasma TV hung on the wall. 

Well, I push the button on the remote and nothing happens.  I can see the light on the remote coming on with each press of the button, so I feel relatively certain the remote is not the issue.  However, I took the batteries out and tested them anyway.  They were just fine.

The fact that this happened overnight had me puzzled.  I searched the web and found many people discussing this issue, with many replacing the IR receiver in the TV.  There was also discussion about how the output voltage of the IR receiver varied…sometimes low and sometimes high.  Well, in one of these threads I ran across the "remote control in" jack issue posted by vp123ca.  This made some sense.  There is a switch in the "remote control in" jack that disconnects the front remote sensor when a "remote" remote sensor is plugged in.  Over time, the switch corrodes and disconnects the sensor on the front of the TV.  Due to the age of the TV, I found this to be completely plausible.  But, I wasn’t even sure if I had one of these "remote control in" jacks.

A quick inspection of the back of the TV validated that it did indeed have a "remote control in" jack!

So, I got my trusty can of contact cleaner out and "spritzed" it.

I sprayed a bit of contact cleaner in the hole and then used a male 1/8" jack and worked it in and out (sounds a little risqué’) to facilitate the cleaning.  The results?  FIXED!