You might try these links -- the third is of particular interest since you can buy a manual there.
http://www.suertenich.com/html/tester/tubetester.html
http://www.vacuumtubes.com/I-177.html
http://www.vacuumtubes.com/manuals.html
You may also need to try to find an adapter (socket adapter kit MX-949/U) to test a wider array of tubes. I don't have any personal experience with this tester, but I hope this info helps.
http://www.suertenich.com/html/tester/tubetester.html
http://www.vacuumtubes.com/I-177.html
http://www.vacuumtubes.com/manuals.html
You may also need to try to find an adapter (socket adapter kit MX-949/U) to test a wider array of tubes. I don't have any personal experience with this tester, but I hope this info helps.