Measuring the voltage across each capacitor would help you find out which diode shorted when it was stressed finding out the conductivity of soda.

Remember the "Pepsi Syndrome" skit on SNL? I know this might be a long shot, but do this: Lightly sand the charging contact posts on the socket that is "not working"...The spilled soda might have dried over the contacts enough to form an "insulating baste" when the syrup dried.