Peter,
The driver lamps in the display magic black boxes consist of neon
type bulbs. Like all neon devices, over time they become
flaky. Many years ago I had success in replacing some of the neon
lamps in one of my displays, which solved the problem - for a few
years. A side benefit was that I learned some new words and even
invented a few even newer ones!
I'd also thought about replacing the original display portions of the
boards. As I recall, there was an issue with the way the dividers
and display works and I don't believe they work on decades. I may be
wrong on that, but that's what's stuck in the krell of my memory. If
you should wind up replacing the nixies and their drivers I would be
very interested in what you do. I think the 5245L counters were a class act.
Burt, K6OQK
Subject: [time-nuts] HP 5245L Question
I read the recent comments on the HP5245L with interest. I have
several of these excellent instruments and recently used one in
anger, to repair a 20GHz Signal Generator (HP 70000 Series) for my
employer, thus saving them circa ?10000.
My question is, has anyone experienced the deterioration of the
photo cells, another early semiconductor device with somewhat less
than a forty years life expectancy? These seem to fail randomly, and
I guess it is also a hygroscopic problem.
I wondered about replacing nixie tubes and associated drivers with 7
segment LEDs in one of my (already hacked) units, to make it more
reliable. I would use the BCD to drive the display, thus requiring a
new interface board to be designed. I wonder if anyone else has
considered such a radical remedy to the failing photocell problem?
In case anyone is wondering 'WHY BOTHER?', my defence is that I
too have an extensive collection of the plug ins, extending the
usefulness of the basic instrument way beyond my budget for more
modern equivalent instruments.
Hope this question is not considered too far off topic for this forum.
Peter Worrall
G4GJL
London
Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California U.S.A.
[email protected]
K6OQK
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