Yes it's been under some scrutiny....
every time I would take the phone away from the console table the handset volume would drop
Bring it back and it's would be ok...
I'm afraid it could be part of the modern malaise, oxidised connections etc. Any how after 10 years of service I think it's time for a new one.
We thru everything away after the lighting strike 11 years ago, every part of the phone system cables etc got fried