Dm 20 serial number

Serial numbers can't be crossed over this way.

Try this site: http://www.iboats.com/Johnson-9-9-hp-Outboard-Manuals/dm/view_id.440464

Dm-30-60367

The serial number should be located on the voice recorder battery or memory card compartment, if they mean the serial number of the DM-20.

your problem is red or black lead wire broken

It's on a green square piece of paper that came with all the literature. It's a 20 digit long series of numbers.

You may wish to call Olympus technical support and they will email you a link to the DSS Player software that you need for the recorder as they will need to provide you a serial key so you are able to install it. Their telephone number is 888-553-4448 option 5 and then option 2

More than likely you would need to format the device. This will clear all data that has been previously recorded. In your menu there is a format option. Run that and the memory would then be reset.

Check the batteries contact especially at the battery cover. It may happened rusty if you leave the battery for a long time when the recorder not in use.