I think the 2 box solution is acceptable.
jdragoset showed how he did it earlier in this thread and Gapsus used 2 boxes too in the thread I linked earlier:
https://www.eevblog.com/forum/repair/tektronix-465/msg672083/#msg672083
By using a plastic jiffy box and potting it you have options on where to place it ....within reason.
Thanks tautech, that is true. Sometimes I think I should stay away from trying to do everything as "original" and make it easy on myself. But the challenge is hard to resist
![Cool 8)](https://www.eevblog.com/forum/Smileys/default/cool.gif)
Certainly, physical sizes of parts have shrunk so much today. So, how did Tek make such a compact unit with all those components some 30+ or more years back, when there were no parts like today? Apart from the EHT tripler section, it contains a bunch of caps, diodes and resistors for the rest of the HV circuitry. I am amazed!
Another note: I did not have to use too many diodes to get to 13 kV. Only 4 diodes and 4 caps even though I hooked up 6 of each to begin with that gives about 18 kV. The schematic does not indicate what the EHT is even though it clearly says it is a x3 multiplier. I decided to stay at just 13 kV based on a 465 schematic where it indicates the anode voltage as 14-16 kV. Considering the age of this 465M, 13 kV should be a safe bet I think where I still have good intensity and focus.
Sadly, the replacement U 550 unit I got also has the same identical problem as the unit that was in the scope, which was hard to believe. It cost me more than US$ 100.00 by the time I had it in my hands. That was all down the drain to say the least.