01-05-2012, 12:16 AM
Sorry just looked at the diagram, I was thinking that it has a separate mixer and osc tubes. I'm pretty sure the 70 does but the 71 doesn't. So injecting the signal in to the grid of the mixer is fine.
I'm a little surpized that you can't pass a signal from the grid of the IF amp tube and adjust the trimmer. Should have the generator turned down fairly low to prevent overload. Check the resistance of the windings on the IF transformers. Also check plate and screen voltages on the IF amp tube should be around 200v or so.
Terry
I'm a little surpized that you can't pass a signal from the grid of the IF amp tube and adjust the trimmer. Should have the generator turned down fairly low to prevent overload. Check the resistance of the windings on the IF transformers. Also check plate and screen voltages on the IF amp tube should be around 200v or so.
Terry
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got it!
Terry
![[-]](https://philcoradio.com/phorum/images/bootbb/collapse.png "[-]")
