[Gogar]

Get a Sonos connect- RCA outputs and you're good to go! Can stream most services.

Any speaker can be serviced; I'd suggest if you rebuild or replace a component on one side that you do both.
Moving components made out of paper can almost be considered "wear items" like brake pads and most certainly were never expected to last 40-50 years, but it's great if they do!

Those speakers on top are probably not as loud as the bottom ones, but they are probably much smoother.