07-17-2024, 05:45 PM
The Philco 40-120 radio has 6 Loctal tubes. Each of the tubes has a metal attachment that comes out of where the center keyed pin goes. 4 of the tubes, 7C7, 7A8, 7B7, and 7C6 are all connected via this center connection which then goes to a chassis ground. The 35A5 and 35Z3 have to connection to this center pin. Are they supposed to? If not does it have to do with the fact that the 35Z3 and 35A5 are the rectifier and Output tube?
On the attached schematic, what denotes the center pin for each tube? I do not see anything that comes out of the tubes and goes to a ground.
I am still learning so bear with my ignorant questions and thank you in advance.
On the attached schematic, what denotes the center pin for each tube? I do not see anything that comes out of the tubes and goes to a ground.
I am still learning so bear with my ignorant questions and thank you in advance.
![[-]](https://philcoradio.com/phorum/images/bootbb/collapse.png "[-]")
