How to reference a second Combo box’s output based on previous Combo Box’s Row source

Hi all,

I am looking for a way to reference a combox2 's output (which shall be a range of values pulled up from Sheet1) ; based on the combobox1's row-source and not combobox1's values

My attempt:

Private Sub OKOK_Click()
If vendor_part1.Value = True Then

ComboBox1.RowSource = ("Couplings")
' Couplings are a range of values from my sheet
Else
ComboBox1.RowSource = ("Mumblings")
' Mumlings are a range of values from my sheet
End If


End Sub
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Private Sub Typeofmanual_Click()
If ComboBox1.RowSource = ("Couplings") Then

txtbx_typeofmanual.RowSource = ("Typeofmanual")

'type of manual is a range of values that I named it that way.

End If


End Sub

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See attachment if necessary