ASP.NET CORE EF Specified cast is not valid

Sorry I do not understand why you do not let me list my model, I have this image with the error

public IEnumerable GetBalances ()         {             var list = new List ();

        using (var db = new ApplicationDbContext())

        {

            var query = db.Balanza;

            listado = query.ToList();
        }

        return listado;
    }

My model is this

 public class Balanza
   {
    [Key]
    public int BalanzaID { get; set; }

    [Display(Name = "Codigo de Balanza:")]
    [Required(ErrorMessage = "Debe ingresar el codigo de la Balanza")]
    [MaxLength(20, ErrorMessage = "El campo no debe exceder 20 caracteres")]
    public string Cod_Balanza { get; set; }
    [Display(Name = "Marca:")]
    [Required(ErrorMessage = "Debe ingresar la marca")]
    [MaxLength(20, ErrorMessage = "El campo no debe exceder 20 caracteres")]
    public string Marca { get; set; }
    [Display(Name = "Serie:")]
    [Required(ErrorMessage = "Debe ingresar la serie")]
    [MaxLength(20, ErrorMessage = "El campo no debe exceder 20 caracteres")]
    public string Serie { get; set; }
    [Display(Name = "Fabrica:")]
    [Required(ErrorMessage = "Debe ingresar la fabrica")]
    [MaxLength(20, ErrorMessage = "El campo no debe exceder 20 caracteres")]
    public string Fabrica { get; set; }
    [Display(Name = "Modelo:")]
    [Required(ErrorMessage = "Debe ingresar la modelo")]
    [MaxLength(20, ErrorMessage = "El campo no debe exceder 20 caracteres")]
    public string Modelo { get; set; }
    [Display(Name = "Descripcion de Balanza:")]
    [MaxLength(150, ErrorMessage = "El campo no debe exceder 150 
   caracteres")]
    public string Des_balanza { get; set; }
    [Display(Name = "Tipo de Balanza(1:manual,2:automática):")]
    [Required(ErrorMessage = "Debe escoger el tipo de balanza")]
    public char Tip_balanza { get; set; } //1:manual, 2:automatica
    [Display(Name = "Tipo de Situación de 
   balanza(1:propio,2:alquilado,3:ajeno):")]
    [Required(ErrorMessage = "Debe escoger el situación de la balanza")]
    public char Sit_balanza { get; set; }//1:propio,2:alquilado,3:ajeno
    [Display(Name = "Propietario de la balanza:")]
    [Required(ErrorMessage = "Debe ingresar el propietario de la balanza")]
    [MaxLength(20, ErrorMessage = "El campo no debe exceder 20 caracteres")]
    public string Pro_balanza { get; set; }
    [Display(Name = "Capacidad máxima:")]
    [Required(ErrorMessage = "Debe ingresar la capacidad máxima")]
    [Range(0, 9999999, ErrorMessage = "Íncorrecto, no puede ser menor que 
    0.")]
    public decimal Cap_maxima { get; set; }
    [Display(Name = "Capacidad mínima:")]
    [Required(ErrorMessage = "Debe ingresar la capacidad mínima")]
    [Range(0, 9999999, ErrorMessage = "Íncorrecto, no puede ser menor que 
     0.")]
    public decimal Cap_minima { get; set; }
    [Display(Name = "Ubicación:")]
    [Required(ErrorMessage = "Debe ingresar la ubicación")]
    [MaxLength(20, ErrorMessage = "El campo no debe exceder 20 caracteres")]
    public string ubicacion { get; set; }
    [Display(Name = "Fecha de Fabricación:")]
    [Required(ErrorMessage = "Debe ingresar la Fecha de Fabricación")]
    public DateTime Fec_fabricacion { get; set; }
    [Display(Name = "Fecha de Ingreso:")]
    [Required(ErrorMessage = "Debe ingresar la Fecha de ingreso")]
    public DateTime Fec_ingreso { get; set; }
    [Display(Name = "Estado(1:activo,2:inactivo):")]
    [Required(ErrorMessage = "Debe ingresar la Fecha de ingreso")]
    public char Estado { get; set; } // 1:activo,2:inactivo
    //datos de auditoria
    public string usuario { get; set; }
    public DateTime? Fec_modificacion { get; set; }
    public DateTime? Fec_stamp { get; set; }
    public string programa { get; set; }

   }

the modelBuilder is this:

   modelBuilder.Entity("REQ.UI.WEB.Models.Entities.Balanza", b =>
            {
                b.Property<int>("BalanzaID")
                    .ValueGeneratedOnAdd();

                b.Property<decimal>("Cap_maxima");

                b.Property<decimal>("Cap_minima");

                b.Property<string>("Cod_Balanza")
                    .IsRequired()
                    .HasAnnotation("MaxLength", 20);

                b.Property<string>("Des_balanza")
                    .HasAnnotation("MaxLength", 150);

                b.Property<char>("Estado");

                b.Property<string>("Fabrica")
                    .IsRequired()
                    .HasAnnotation("MaxLength", 20);

                b.Property<DateTime>("Fec_fabricacion");

                b.Property<DateTime>("Fec_ingreso");

                b.Property<DateTime?>("Fec_modificacion");

                b.Property<DateTime?>("Fec_stamp");

                b.Property<string>("Marca")
                    .IsRequired()
                    .HasAnnotation("MaxLength", 20);

                b.Property<string>("Modelo")
                    .IsRequired()
                    .HasAnnotation("MaxLength", 20);

                b.Property<string>("Pro_balanza")
                    .IsRequired()
                    .HasAnnotation("MaxLength", 20);

                b.Property<string>("Serie")
                    .IsRequired()
                    .HasAnnotation("MaxLength", 20);

                b.Property<char>("Sit_balanza");

                b.Property<char>("Tip_balanza");

                b.Property<string>("programa");

                b.Property<string>("ubicacion")
                    .IsRequired()
                    .HasAnnotation("MaxLength", 20);

                b.Property<string>("usuario");

                b.HasKey("BalanzaID");

                b.ToTable("Balanza");
            });

In another project that I have if it works normally, but when I create this project I get that error when I show it in View as List

   public IActionResult ListarBalanzas()
    {
        var model = balanzaAD.GetBalanzas();
        return View(model);
    }

I will be attentive if any other information is needed to solve this problem. I already tried to drop the database and again do the Update-Database to see if that was a problem but it does not solve it.