Dell has the service manual available on their support site 
http://downloads.dell.com/Manuals/a...aptop/inspiron-1521_Owner's Manual2_en-us.pdf
http://downloads.dell.com/Manuals/a...aptop/inspiron-1521_Owner's Manual2_en-us.pdf
I have a hard copy of the manual.
The manual does not help with the problem I have.