[Test-Equipment] nixies and hp counters

[Eugene Hertz]

Hello all,

I have an HP 5245L nixie counter with a 5253A plug in that will let it go to 500mhz.

I think I have two problems. First, one of the nixie displays has a strange behavior where certain numerals (not all) will sort of "half display" like the number 4 might have some of its legs glow. But oftern after 5+ seconds the rest of it will glow as it should have originally. Seems that some numerals slowly "reveal" themselves after several seconds. Other times the numeral does not display.

Could this be a nixie tube problem or perhaps a driver problem? (or whatever discrete components make the nixie work?) I am really hoping it could be a faulty cap or something simple.

Any one on any piece of nixie equipment ever see a numeral slowly display itself? 

Question 2. Does anyone have the specs as to what the sensitivity of the 5253A and the 5252A should be? (I forget which I have so I might as well check both!) Seems 100mv p-p is not triggering it.  Anyone have an idea what might cause insensitivity?

Anyone have any circuit diagrams? Bama has the 5254C and the 5253B. Perhaps they are similar enough for my purposes?

Thanks