05-26-2019, 02:07 PM
Turning my attention back to under the chassis...
We have to modify the antenna coil in order to add AVC to this set, removing one wire lead of the coil's secondary winding from the ground terminal, adding a terminal to the coil form, and soldering this lead to the new terminal.
Please note that one lead of the antenna coil primary is connected on top of one lead of the antenna coil's secondary winding. This means that you must carefully undersolder the ground terminal, (very carefully) unwind the primary lead from the ground terminal, and then (also very carefully) unwind the secondary lead. And once that is done, wrap the primary lead back around the ground terminal and solder it back in place, leaving the secondary wire dangling for the moment.
[Image: https://philcoradio.com/images/phorum/70mod/70_007.jpg]
I found a solder terminal in my pile of junk. You can also sacrifice a terminal strip by using its ground lug as a terminal.
[Image: https://philcoradio.com/images/phorum/70mod/70_008.jpg]
Remove about 1/3 of a turn of the secondary winding, poke the lead through the hole in the form above the new terminal, and solder the lead to your new terminal.
[Image: https://philcoradio.com/images/phorum/70mod/70_009.jpg]
Now the primary and secondary windings are isolated from one another, and AVC may be applied through the secondary of the coil.
We have to modify the antenna coil in order to add AVC to this set, removing one wire lead of the coil's secondary winding from the ground terminal, adding a terminal to the coil form, and soldering this lead to the new terminal.
Please note that one lead of the antenna coil primary is connected on top of one lead of the antenna coil's secondary winding. This means that you must carefully undersolder the ground terminal, (very carefully) unwind the primary lead from the ground terminal, and then (also very carefully) unwind the secondary lead. And once that is done, wrap the primary lead back around the ground terminal and solder it back in place, leaving the secondary wire dangling for the moment.
[Image: https://philcoradio.com/images/phorum/70mod/70_007.jpg]
I found a solder terminal in my pile of junk. You can also sacrifice a terminal strip by using its ground lug as a terminal.
[Image: https://philcoradio.com/images/phorum/70mod/70_008.jpg]
Remove about 1/3 of a turn of the secondary winding, poke the lead through the hole in the form above the new terminal, and solder the lead to your new terminal.
[Image: https://philcoradio.com/images/phorum/70mod/70_009.jpg]
Now the primary and secondary windings are isolated from one another, and AVC may be applied through the secondary of the coil.
--
Ron Ramirez
Ferdinand IN
