Here are some good reads I have found on the subject.
http://www.tungsol.com/html/faqs7.html
http://www.alltubetesters.com/articles/howto_test_tubes.htm
http://www.alltubetesters.com/articles/tester_guide.htm
http://amplitrex.com/
http://www.maximatcher.com/
http://www.tungsol.com/html/faqs7.html
http://www.alltubetesters.com/articles/howto_test_tubes.htm
http://www.alltubetesters.com/articles/tester_guide.htm
http://amplitrex.com/
http://www.maximatcher.com/