Original link below. Looks like the PDF link is dead :(https://nerdomancerofdork.wordpress.com/2014/07/10/old-school-armor-class-conversion-table/
Thanks! I'll update the post. Unfortunate about the pdf but and img download should be an easy work around.
That chart is in error. AC 2 is plate and shield in base 9 descending AC and base 10 descending AC.