I bought an Olympus DM-520 (I think was the number) about ten years ago.  It was a great tiny device and I used it to record everything.  Recently, the power slide switch has stopped working. It's a mechanical switch with some sort of spring to make it return to a center position.  Contacting the Olympus distribution point, I found that they no longer support that model and they suggest I purchase a DM-720 as a replacement.  After the covid thing goes away, I will have a friend take a look at the switch.  If he can't do anything with it, I'll see if I can justify buying the newer model.

Howard