I have a Sony ICF-2010, one of several classic Sony digital shortwave radios. (The only thing "wrong" with it is that lacks stereo FM.)
It uses two batteries -- three D cells for the main power, two AA cells for the clock, control, and memory. One of the contacts for the latter broke loose, and I had to glue it back in place (using Goop, rather than epoxy), inserting some plastic shims for support.
When I reassembled the radio, the Power switch had no effect; it wouldn't turn on. The ICF-2010 is unusual in that the power and antenna connections are made through spring-loaded contacts to the main board, so that when you remove the back, you don't tear loose a bunch of fragile connections. I tried connecting them with jumpers, but still no luck.
Then I remembered the Main Power switch on the left side and checked it. It was Off.
Duh. Duh, duh, duh.