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!
Is your 0D3 glowing inside (the tube not outdoors)??? Is the 10K resistor 10K?? In terms of amplitude the 6SL7 is being used as cathode follower to give a low impedance output. Wouldn't expect to see a lot of gain there. Amplitude is probably going to be about the same. The other half of the 6SN7 is the audio oscillator which generates the 400cy tone for the modulation.
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!
Well, I replaced the Atten Resistors and buttoned up the unit.. I did a final check at 5 frequencies across the bands and recorded the values.. when I hit band F it wouldn't start to oscillate until about 20 mhz. From 13 Mhz thru 20Mhz No signal output.. that also was the case on the harmonics it didnt start to work until 90 mhz..
1st question What would cause the loss of frequencies and 2nd how do I improve the accuracy..
1 Cln the bandswitch and or replace the osc tube.
2 Alignment
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!
Is the F band adjustment the trimmer next the toggle sw?? If so give it a shot of deoxit spin it around a couple of times and let it dry out for while. Then give it a try. If that doesn't do it try compressing the coil just a little. Seems like your osc doesn't have enough feedback.
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!
Ok, Tried all of that same problem..I even replaced the trimmer and coil from a parts set same problem.. however I was able to get down to about 20 mhz before I lost signal..I tried to measure the grid of the OSC Tube pin 6 says it should be -.6 volts I get -.04 volts..
When I go to other bands I get over -6 volts up to about -20 volts on band A..
PS Ready to give up on this.. All other bands work good...
Skip...
(This post was last modified: 06-24-2017, 09:40 PM by vecher.)
![[-]](https://philcoradio.com/phorum/images/bootbb/collapse.png "[-]")
