I thought that there was actually an exchange of matter between the cathodes
going both ways when all the cathodes are on alternatively.
Which means that if only 1 or 2 cathodes are used, theses cathodes erode faster.
I don't know if the sputtering on the glass in the front is also worse on the
f
Alic,
Cathode poisoning only affects the unused digit. So it isn't a reason to
replace a tube, as the affected numbers are never used. The only time I
could see it being an issue is in the hours tube that you might go from
displaying civilian time and then you want to display military time.
I agree about breaking 'em and uneven wear, and the digits that get
cathode poisoning aren't getting used, so who cares?
I was tinkering around on the code for my oldest clock and checked the
hours tube. Couldn't see any difference after 15 years of operation. The
first 9 years it was on 24/7.
