I've had the agent inside overnight to make sure it's warm and dry but the playback of the present tape is all garbled. Fast forwarded and rewound the tape a couple of times but it doesn't seem to help. My attempts to record a message have the same results. Checked the batteries with a multimeter and they appear to be fine. I believe the humidity and subfreezing temps have damaged the tape.
Anyway I'll have a look around mt town and see if I can find a new tape.