MacBook with original wireless card would only connect within a few feet of an access point. I used the fixit guide to open it and make sure the antenna was correctly connected, but that did not solve the problem. So I decided to replace the wifi card with the n model.
When the part arrived, I used the fixit guide again to install the replacement. It took about an hour and worked perfectly.
I used an ice cube tray as a screw sorter. There is another MacBook in the family with a bad optical drive. I might repair it if I find a low cost replacement drive.