[RodB]

Hi Phil - This is where schematic reading gets more intuitive. The tubes you have are generally known as double ended, thus there is a tube electrode connected to the top cap. Most of the tubes you will be working with on these sets will have the cap wire connected to the control grid of the tube, or it is also called grid one. Be gentle with the cap as it was glued down at the factory and 75 year old glue doesn't always hold nowadays. Tubes without the cap are single-end and will have a S in the tube number, as in 6SQ7 versus it's capped counter part 6Q7. So in your diagram you can see the small black square on the left side of the tube where the grid connects indicating that the cap is the grid connection. You'll often read here that you could touch the grid cap with a finger to listen for a response.