[time-nuts] time-nuts Digest, Vol 22, Issue 20

[Bill Hawkins]

> Looking to get good colour photos of some of these 
> older HP counters (and similar offerings from other
> manufacturers) in the pre/early Nixie etc period.

Here's an opportunity to own an HP 522B for $25, including
shipping in the US. The unit has 5 decades of ten vertical
neon indicators each. It works. Yes, it's a 100KC counter/
timer.

I got it from a blasting cap plant where I worked in the
early sixties. It was used to measure the delay time of
time delayed blasting caps, used to remove successive
layers of rock from a quarry or tunnel wall. The start
pulse came from the blasting machine, attenuated. The
stop circuit was normally closed by a pencil lead held
in alligator clips for quick replacement. The cap broke
the lead when it fired. For a while, it was used in
Pinewood Derby races. It has never been exposed to weather
and looks new inside.

Bill Hawkins
bill at iaxs.net