Track the changes in the entries of the table

Hi,

How to c when and by whom the stnadard table has been modified.

Through SPRO some changes are done which are getting reflected in a standard table.

Though Log data changes in the technical settings of the Table in se11 is checked, im not able to c the changes using the tcode scu3.It displays "No logs Found" .

I tried to search the tables CDHDR and CDPOS,but of no use.

Please give some inputs in this regard.

Thanks in Advance.

Dharani.