Small workspace with large possibility to upgrade, still missing some crucial components (like oscilloscope) but I have access to much better equipment at work, and usually this is enough for working on home projects.  Upgrading when I have good deal or when ever it's possible. If it looks like a mess, it's not, trust me, it gets worse. 

Updated schematic with comment of "Thialf" about adding a series resistor of 100E in the DATA IN line of the Neopixel LED strip. This resistor will limit any latch-up current that can flow into the DATA IN line when the power supply is switched off, but the microcontroller is still sending data to the LED strip.  

Interestingly I had little or no interference problems and my home has plenty of wall-warts. Maybe it's because I retuned the IF transformers to 518KHz with a 139pF external cap and I was using a tuned loop antenna also tuned to 518KHz. All I did was wait for a nearby Navtex slot to transmit and then tuned the IF transformer slugs iteratively for maximum signal strength. Have you guys tried this?

Yes, those are the ones I used. Got them from Mouser. They say they have 3 064 in stock curently. What you can do nevertheless is to eliminate things that make a noise in your home.

Dear Rainer, Few days ago, I finished the hardware work on thiis beautifulll project and now I would like to share with you and other users of CubeCurveTracer some experiences and plans. I have some questions too. 1. I have made some improvements In MainWindow_new. There is only some design change which more corresponds to my thick fingers and maybe this design is safer from quick finding pushbuttons point of view. In addition I changed the preset 12V in heating power supply to 12.6V which is more in line with the reality of tubes heating. You can find this changed project in attachment. This includes executable file and MainWindow QT file.  2. I have just started my next work on the project which will be the implementation a rotary encoder to change the way how to  change input values to eliminate need of the keyboard. What do you think about this idea? 3. During the tests I found some inconsistency in the behaviour of the power supply. For example (using new GUI) until I set the current limit of Anode power supply to at least 4 mA I cannot reach the maximum output voltage of 400V. Of course - these values correspond to the quiescent current through the resistor R15. Maybe it would be a good idea to plug upper outlet of this resistor R15 from GND to the left side of R7 (connected to the FET as well). This will hopefully eliminate measurement of this quiescent current but I don’t know if it will affect the internal calculations for the Curve Tracer mode. 4. I would like to discuss with you one unfortunate thing that has happened to me. During the anode supply tests, (which worked well including current limitation), I made accidently short circuit to the output terminals (at the seting of maximum voltage and current).  The result: burnt Q6, R14 (!!!), R11, LT1079, LT 1078 and fuse – most expensive parts of the board. I don’t know why current limitation did not work in time, short circuit is after all normal if we use laboratory power supply, BUT: The destruction of Q6 (short circuit between of all electrodes, because of not working current protection) and subsequent interruption of R14 (1 Ohm/2W!!!)  caused full voltage 400V to be sent to LT1079 and LT1078 and they were destroyed as well. My suggestion is to significantly increase the power of R14, which must never be destroyed to open circuit. This will at least protect the expensive IC’s. In fact, the fuse must be blown earlier then the R14. However, this still does not solve why current protection by short circuit did not work. After replacing of all burnt parts the board works again well. I'm now a little bit afraid of trying another short circuit :-) Thank you for any comment(s)