Combobox not loading with results from Linq query

x77, hopefully I answer your questions correctly.  dc is a data contents and vwTechSelectNameChanges is a view from Sql Server. So I believe Tnames (should be TMnames my typo) is an object. You say TMNames is not a Datasource but it was working as a datasource before. I could use something like this:
        For Each Change In TMNames
        Change.HasValue = False Then      
                 cmbTMName.Items.Add("")
       Else
          cmbTMName.Items.Add(Change)
       End If
This causes other issues with the other comboboxes for some reason and I'll need to fix Change.HasValue = False Then       line something with the null value is an issue. In this case null is a valid choice. any ideas.

TMNames is Ienumerable, not datasource.
For Each - is correct as mentioned.
Try to append  ".AsDataView" to TMNames to create the dataSource.

.AsDataView wasn't an option.  

Use Fore each  to add items to como.

cmbTMName.Items.clear

For each value as string in cmbTMName

  cmbTMName.Items.add (value)

next

DataSource on combo is dificult to manage.

It ever select the firt item by default.

Also
cmbTMName.Items.clear
cmbTMName.Items.addRange(TMName.ToArray())

Michmatch on previos:
For each value as string in TMName

x77,  I know I keep going back to the datasource but I created another query based on a table this time and the results worked fine as a datasource. So then I thought maybe its a view issue so I tried a different view and it works fine.  So theres something about this view it doesn't like. I did drop it and bring it back into my data content. Not sure if this would cause an issue. And as I mentioned before, it was working fine for about 4 months and then our Sql Server goto switch to a different server and then the issues started.  any Ideas...

Test with no Typed DataTable

Dim T As DataTable = Me.DataSet1.R17TDPOS
Dim Query = From Row As DataRow In T.Rows Select Row("Sup") Distinct
Me.ComboBox1.DataSource = Query.ToList

OK, I haven't tried all your suggestions but adding Distinct semi helped. I now get values but not all. I think the problem is when there is a null value. It looks like when it hits null it stops where its at and olny brings over the values before null value. But let me look at some of the other suggestions

Dim Query = From Row In Me.DataSet1.R17TDPOS _
   Where Row.SERV IsNot DBNull.Value _
  Select Row.SERV Distinct