You also may notice (we did at the radar range) that there are more RF sources each year so combine that with age they can fail over time.
Since you are a seasoned user/owner you know these require to be on the same side of the power line and that is well discussed so I'm going with "try a new set."
I am using a D-Link EBR 2310 wired router with two Plaster Networks power-line modules. They are about five years old.
An Ethernet cable is connected to the router and then to a PLN3 module that's plugged in to an AC outlet near the router. Another PLN3 module is plugged in to an AC outlet right behind my LG 55" LED/LCD HDTV, with an Ethernet cable connected from the module directly to the TV.
I've had fantastic connections since using the power-line setup, but in the last month since we returned from a vacation, it keeps getting disconnected from the TV. I also have an Ethernet cable from that module to my PS3 with the same problem.
I tried re-setting the router with a paper clip as instructed but couldn't do that. In desperation, I unplugged the module that is connected to the router, and the network is once again working. But, it is a PIA to keep doing this.
Is it possible these modules go "bad" after a while? I've noticed how warm they get so I wondered about the constant heat effect on the electronics.
Comments and suggestions are most welcome!