At the moment on the crt plug board there still is the original circuit for cathode modulation with the 3 video amplifier transistors as shown below ...
- ccrt2.JPG (153.37 KiB) Viewed 16320 times
Pretty much the circuit on the board below the 3 18k resistors on the positive are all connected up and same goes for the emitters 470 ohm no connection end they are not to ground so i thought it must be to a negative supply .
- CCRT.jpg (58.59 KiB) Viewed 16320 times
Power supply for the video amplifier transistor same as below 100 volts connected up it drops to around 57 volts .
I did try to see if i could use it as is and incorporate it your circuit Klass leaving the cathode 2.7k resistors ...the 18k is not to far off the 22k and i added resistance to the 470 ohm to bring that up ,i did notice a mistake i have made as that 470 ohm resistor is between the emitter and the 330 ohm resistor .
Scope hooked up to the collector of the C2330 video amplifier transistors getting 4 volt waveform out only ,,,i will correct the circuit to the schematic and try again ...output seemed more due to the negative supply than the 100 volts as that could be adjusted lower with similar results but that's just what i am seeing circuit as is ...as in the sstv schematic always worked fine so more than likely my tinkering at fault .
Since i have no data for the tube at all its all experimental adjusting a voltage on the cathode from ground which seems beam is fully on and more towards the positive it should start to extinguish cut the beam if i am not mistaken ..an experiment to test the correct range is some thing would be good a correct procedure .
Also if i have not got the control Grid a correct voltage range i would think this would effect the results seen or over ride the cathode test ...
All i can do is try and jot down the results and see if there is a pattern to the correct path ,i must be close as i can at least bring up a display .
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.