Quote:
Originally Posted by Retired
Lo and behold a result; I can now see sparks on both LOPT valves and also on the single wire into U25 (Anode?) but not the other two wires on U25. The sparks are just visible on the top caps with a nice trail on U25.
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There's a lot more volts on the U25 anode than on the LOP anode or boost diode cathode. Hence the bigger spark. The spark on the DC side of the EHT rectifier is a lot weaker than on the AC side. Typically the AC spark is hot, vigorous and blue; the DC spark is weak, spindly and yellow. You may need to earth the tool that's drawing the spark to get a good spark from the EHT rect cathode. If the U25 heater is glowing there should be EHT present.
Before fiddling with the ion trap you may want to check the CRT operating voltages. Check that the brightness control varies the grid voltage, that there's some volts (few hundred?) on the 1st anode and that the cathode voltage is fairly close to the grid voltage. It's OK to short the grid to cathode when you're aiming for first light. This at least ensures that the CRT isn't cut off by the grid/cathode voltage.
You are tantalisingly close to first light.