It appears that Library of Congress call number searching in UW Libraries Search has become more reliable. Here's a little (silent) video of how to do it. Note that the format of the call number needs to be precise:
- no space between the initial letters and numbers
- a dot after the first numeric set
- no space between the second letter and numeric set
- a space between the second numeric set and the next letter, etc.
You'll see what I mean by the above in the video:
http://screencast.com/t/blZ9WtbkPEQ