The radio had been off and untouched all day. Had been working fine for
about 3 days. I came home and once again the 12:00 was flashing, and all the
presets cleared.

Oh boy. It sure sounds like the cells unconnected. If there's no backup inside,
that's it.

Although I don't know about SW receivers, much of the newer equipment having
memories, such as my few years old Radio Shack 2M HT and, I suspect, my new
Grundig eTR7 SW RX, as well as computers, musical keyboards, etc., have either
a high capacitance capacitor or a piggyback battery on a chip to retain memory.
Although the cap will sometimes fail due to age, the battery will indeed fail
eventually. And that requires replacing the chip it's on.

As for what Shack will allow you, please let us know. G

Good luck,
Bill, K5BY