Excel 2003 VBA - changing axis scale upon worksheet change

Worksheet with combo boxes. User selects combos linked to a cell and the chart changes according to selections. Need the axis to also adjust to my named ranges.  I would like this to be upon a worksheet_change vs manually calling the macro/code if possible.

I've tried many different ways of doing this and have nothing workable yet. I need this asap and have spent many many hours researching this from examples.


Private Sub Worksheet_Change(ByVal Target As Range)
    Dim ch As ChartObject
    Set ch = Worksheets(Summary).ChartObjects("Chart 16").Select
 
    With ch.Axes(xlValue, xlSecondary)
        .MinimumScale = ActiveSheet.Name("MinScale_LP")
        .MaximumScale = ActiveSheet.Name("MaxScale_LP")
    End With
   
    With ch.Axes(xlValue, xlSecondary)
        .MinimumScale = Summary.Name("MinScale_GFWC")
        .MaximumScale = Summary.Name("MaxScale_GFWC")
    End With
End Sub

This did not work either:
Private Sub Worksheet_Change(ByVal Target As Range)

    ActiveSheet.ChartObjects("Chart 16").Chart.Axes(xlValue).MaximumScale = MaxScale_LP
    ActiveSheet.ChartObjects("Chart 16").Chart.Axes(xlValue).MinimumScale = MinScale_LP
    ActiveSheet.ChartObjects("Chart 16").Chart.Axes(xlValue, xlSecondary).MaximumScale = MaxScale_GFWC
    ActiveSheet.ChartObjects("Chart 16").Chart.Axes(xlValue, xlSecondary).MinimumScale = MinScale_GFWC

End Sub