Trying to make a vision IF and Detector - fun!

[AdrianPH]

OK a bit of an update, progress is slow as I work things through in my head, but within the recent CRT's I got was what I believed to be a 2AP1 tube, a loose base that fell off whilst handling.  So after spending some time with it I thought I would try and see if I could use it.

I am using grid modulation and varying the cathode for brightness, there is quite a low allowed voltage difference between Cathode and Heater on this tube so I had to use a separate 6 volt transformer for the heaters and allow it to float, or connect one side of the Heater to Cathode.

This is the death trap for the unwary at the moment.
   
   

It is displaying the test card from Hedghog, I can not focus it, the focus voltage being done for the DG7-3 not this tube, so either I modify the blue box on the back or fit the other tube.
   

I had major issues with hum bars and trying to find where they came from, in the end, it was a mixture of EHT ripple and heater to cathode ripple both sorted by caps to ground.

I hope to make things a bit better later tonight or tomorrow, My caps between the timebases at plates are at their very limit, so I need to find some 0.1uF at 1 or 1.5 KV.

Adrian