many thanks in advance for your help with this. I would also like to know that tools and parts to buy. The tube is 3/8" though length and color are unknown until I get the spiral balance removed.

We actually have a guide covering this process. Take a look at our non-tilt balance guide here and let us know if you have any other follow-up questions.
You would reverse the installation process by removing the spiral from the mounting bracket using our 75-005 or a pair of needle-nose pliers and slowly raising it to the base of the tube since it will still have some tension. Then unscrew the top of the tube from the jamb and pull the balance out of the top of the window, which will most likely be snug. These windows weren't made to have the balances replaced, so it sometimes requires some elbow grease to remove them.