Chamberlain Garage Door Opener receiver problem
For the past 5 years, my Chamberlain Whisper Drive (model WD822KL) opener has operated flawlessly -- the remotes could activate the door from 200+ ft away (line of site down the street). I also have an outside keypad (~12 feet from the antenna) and a transmitter built in to a Jeep that perform without issue. Last October, my opener stopped responding to all of the remotes and keypad unless they were inside the garage and within 2-3 feet of the opener's antenna. The Jeep's transmitter wouldn't work when the garage door was done, nor when the Jeep was inside the garage and literally under the opener.
The first thing I did was put new batteries in all of the transmitters, but there was no change in the situation. Although there were no diagnostic error light flashes, I purchased a replacement receiver board (mfg date of 08/2008). When the board arrived, the weather had turned cooler and stayed that way day to day (I live in FL) and the receivers all started functioning again. I assumed that there could be a strange short in the logic board attributed to expansion/contraction based on temperature and decided to wait to replace the receiver board (which I did not want to return because of a restocking fee).
Yesterday (May 9), my transmitters again all stopped working unless they were within 2-3 feet of the antenna. The weather has again been consistently warm (85F and above), so assumed it was my heat problem returning. I replaced the receiver board with the brand new one -- but still none of the transmitters work unless they are 2-3 feet from the antenna!
After verifying that my camcorder could see infrared emissions (from my TV remote control), I validated that the safety sensor is at least emitting IR light. And neither logic board indicated any type of sensor alignment failure. In fact, neither board is generating any diagnostic failure code flashes at all.
What other elements of the system could cause transmitter/receiver interference? Or are there other parts of the system that could be failing which cause this behavior?
Any and all suggestions are welcomed, as I am completely stumped.