Here are the 'official' instructions for wiring the 610 Panel into your B&K 650 tube tester. These instructions came directly from my own personal 650 tester, and it appears I am the only living person with such instructions. The 610 Panel isn't a necessity; it is only used to test 'newer' tubes not already accounted for on the original panel. For testing the most common audio tubes, the 610 isn't needed. But if you want to complete the look of your 650, and test tubes like the 6BM8, you will appreciate these instructions. After the wiring is complete, you simply plug the 610 Panel into octal socket #41.