10-13-2020, 11:28 PM
So I tried the acoustic system plugged today, now that I fixed the AF amp.
No, still howls. But sounds mighty nice when it doesn't.
Interesting it does it on BC band but barely does it on FM band.
And it sounds very good on FM.
So...need to break out the scope. See why it oscillates.
Also the sch has an omission: the Voice switch when switches to the Voice mode, also uses another pair of contacts to cut the Feedback signal from the output transformer by loading it with 2.2K resistor to GND. This resistor is not shown.
No, still howls. But sounds mighty nice when it doesn't.
Interesting it does it on BC band but barely does it on FM band.
And it sounds very good on FM.
So...need to break out the scope. See why it oscillates.
Also the sch has an omission: the Voice switch when switches to the Voice mode, also uses another pair of contacts to cut the Feedback signal from the output transformer by loading it with 2.2K resistor to GND. This resistor is not shown.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
![[-]](https://philcoradio.com/phorum/images/bootbb/collapse.png "[-]")
