Anet A6 heat bed stopped working
This is a shot in the dark, but the vast majority of problems with a heating bed stopping to work is usually at the cables/connectors interface.

This is because in printers like the A6, the cable/connector is subject to constant mechanical stress, and - since metal fatigue is a thing - either the solder or the cable core cracks.

You should make good use of your tester to verify the integrity of the circuit in the bed and if it is not toasted you should be able to just repair the connection.

For many printers there exist "strain relief mods" to prevent this type of failure to happen.  The first one showing up for the A6 is a full chain, but normally is enough the have a small enclosure for the connector like this one for the CR-10.