My Cobra Marine handheld radio died on its own!

[IvanJ]

I left it in my boat during the winter. I checked the boat in January, the radio worked just fine. Then I came back in April and when I tried to turn on the radio, it was dead. I thought the batteries were drained, but no - I changed the batteries, cleaned the contacts, even disassembled the unit but couldn't find anything suspicious (water, damaged/wet contacts or anything).

Does anyone have any idea how could my radio die on its own while being turned off?! Did anyone experience something similar with their cobra marine handhelds?