xls to csv

I have an Excel file whose data I need in a comma-delimited text file. I have tried Save As and got only tab-delimited or various other kinds of nonsense I cannot convert to csv. I am focussing on Access as an intermediary, but, if I link to the file and export, the year in the 4th column comes out with decimals, and, if I try to import, using the same specifications, I get emptiness in the first 3 columns. It is probably very easy, but I am pretty well stuck.