Thanks to all for their comments, and to those who supplied their numbers.
Here is the latest and up to date table.
Hmmmm, all 5530/7730/9930 still appear to have been made in 1975, and all 5560/5570/5580/5590 appear to have been made in 1976.
member model year month 1st 2nd nu...
First a Texas sized thank you to Ed in TX for allowing me to scan Tuning Fork numbers 4 and 5. THANK YOU!! :banana: :banana:
Here is an article from TF 4 in the Parts Information section called Semiconductors which deals with transistors, naming codes, form factors, etc.