It sounds like it failed and needs replacement.
I'm not sure if this is the right place to ask this question. Since there are no sub-forum for cordless phones, I decided to post the question here.
I have a Panasonic KX-TG5672 cordless phone which I have been using for almost 4-5 years now. I have two units of it: one near my computer to hook up to the modem & other in my living room. For the last few months, the phone near modem is giving problem continuously. The screen display would go blank even though the charge is full when the phone is in the set. But when taken out of the set, the phone's display shows not words/letters on the screen.
Initially I thought it might be an issue with the battery (HHR-P104). So I interchanged the battery from the living room phone. But then the problem still persisted. But now on the different one. I then changed the phones from one set to other. Still, the problem was occurring on the set near the modem.
After doing some research online, I found some people have had issues when there might be multiple connections near one outlet which tend to reduce the energy intake for the phone. My concern is that I have been using like this for last 4-5 years with no problem. Why is it giving me problem all of a sudden? If the phone could not get enough charge from the outlet with multiple connections, then how come it was working fine for the last few years? Or is the problem entirely on to something else? Could it be that particular set is getting almost dead? What could be the reason?