Private Sub Worksheet_Change(ByVal Target As Range)
If Not Intersect(Target, Range("B5:C35")) Is Nothing Then
Application.EnableEvents = False
R$ = Replace(Target, ",", ".")
V@ = Val(R$)
H% = Int(V)
M$ = Str(V - H): M$ = Replace(M$, ".", "")
Target = Str(H) & ":" & M$
Application.EnableEvents = True
End If
End Sub