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Re: Replace Neon NE-2 with Zener in 141T PSU?


 

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Would you guys ease off long enough for me to type a reply? ?:)


Tom,?Dave,


I wish. ?But the glass stops beta. ?The Kr-85 worked?because it was?inside.


Bob, Elliott,


So many parts in series... sometimes brute force is the best solution, but this one puts me off. ?That's just my personal taste; if you want to do it, knock yourself out.


Elliott,


HP used?1% metal film resistors. ?The pot is a weak point for long-term stability, but since it's in a voltage divider the high-leg tempco compensates the low-leg tempco. ?It's also a small fraction of the total divider resistance, so its tempco is a small part of the total.


In a related thread, Alan Melia suggests adding a LED to illuminate the gas tube. ?If the problem was dark effect, brought on by Kr-85 depletion, that should work around it just dandy. ?I hope someone tries it. ?I can't, my ZZ1000 is still working. ?If I can find a flickering neon at home, I'll try to figure out what wavelength LED is the most effective. ?It will be visible light, not?UV; the glass blocks UV. ?(Also external nuclear?radiation.)


Dave Wise?


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