I've been searching for that oval plug as well,
I have 1 cord and three items that use it.
But,
While searching I found the cord for MicroVaxIII's
that has the high current cut-out in it.
http://www.dealtime.com
searching for "power cord"
Yielded
http://www.techdepot.com/product.asp?productid=27873&affid=673
http://www.computers4sure.com/product.asp?productid=27873&affid=673
John A.