after having repaired my KEI 2410,
i've found one "final" glitch, that i would like to fix, but don't exactly know where to start. also, i'm not sure as to whether there's still some component fault hiding there, or whether this actually is a design flaw of the instrument.
hence,
it would be great if someone could perform a similar test on his/her machine and tell me how it behaves this is how you can reproduce the (at least in my eyes) faulty behavior:
1) switch off the 2410
2) connect a nixie tube (any segment you want) to the output of the 2410.
3) turn down light in lab
4) switch on the 2410 (just switch on power switch, no need to switch the output on), and watch a short blink of the nixie as soon as the 2410 has finished initialization.
so, there is a spike of more than 150V present at the output, although the output is OFF
i verified that with scope and 100:1 probe, the spike goes up to 500V(!) volts. i checked the HV disconnector (COTO) relay, and that's ok. further investigation showed that, during init phase, the voltage directly at the HV output stage creeps up to -1kV (some milliseconds), and then snaps sharply back down to zero volts (microseconds). it seems that the sharp voltage transition is capacitively coupled through the HV-disconnector relay to the output terminals.
yes, i know that the manual tells you to disconnect everything from the output before you switch the instrument on. but that doesn't cut it for an instrument that costs 7 grands
any ideas what to check?