Hoi Poul-Henning,

On Wed, 21 Apr 2021 12:37:13 +0000
"Poul-Henning Kamp" phk@phk.freebsd.dk wrote:

Yes, that's what I am currently doing:
cmd(pm, "DISP OFF,'    '")

(I even think that line came from one of your scripts)

		Attila Kinali

--
The driving force behind research is the question: "Why?"
There are things we don't understand and things we always
wonder about. And that's why we do research.
-- Kobayashi Makoto

In my experience, most of the wear comes from segments that are
activated, but the rest of the display still degrades.

I used VFDs (New Haven Displays,
https://www.newhavendisplay.com/m0216sd162sdar21-p-2076.html) on a piece of
equipment we started shipping in 2000. We shipped 2-3 dozens over 5 years.
They are still used. Under normal conditions, 4 digits are used in the
middle of a 16 character line, 24/7/52 (except for a handful of spares).
When these units come back for service, you can clearly tell the difference
between those 4 digits and the others, but compared to a new one, I would
guess the rest degrades about half as fast as the digits that are used. The
biggest difference is that the digits that are used are dim and blotchy
while the rest is less dim and still pretty uniform. We replace the
displays when they are too bad (up to the service tech unless the customer
specifically asked for it), even though the units are mostly remote
operated so the display is not crucial, unless they have issues
requiring operating the unit locally. We started replacing them about 5-7
years after shipping the first ones.

Didier KO4BB

On Wed, Apr 21, 2021 at 7:38 AM Poul-Henning Kamp phk@phk.freebsd.dk
wrote:

Intriguing. I had an email about a modification of a 2W M140 as a way to repair broken VFDs.
Might work but the older displays may be better, as there are gaps in the grids that a laser beam can shine through.

I would guess that if it does work, its by spot heating of the phosphor.

From: Didier Juges shalimr9@gmail.com
Sent: 22 April 2021 14:01
To: Discussion of precise voltage measurement
Subject: [volt-nuts] Re: Diplay off command for HP3458

In my experience, most of the wear comes from segments that are
activated, but the rest of the display still degrades.

I used VFDs (New Haven Displays,
https://www.newhavendisplay.com/m0216sd162sdar21-p-2076.html) on a piece of
equipment we started shipping in 2000. We shipped 2-3 dozens over 5 years.
They are still used. Under normal conditions, 4 digits are used in the
middle of a 16 character line, 24/7/52 (except for a handful of spares).
When these units come back for service, you can clearly tell the difference
between those 4 digits and the others, but compared to a new one, I would
guess the rest degrades about half as fast as the digits that are used. The
biggest difference is that the digits that are used are dim and blotchy
while the rest is less dim and still pretty uniform. We replace the
displays when they are too bad (up to the service tech unless the customer
specifically asked for it), even though the units are mostly remote
operated so the display is not crucial, unless they have issues
requiring operating the unit locally. We started replacing them about 5-7
years after shipping the first ones.

Didier KO4BB

On Wed, Apr 21, 2021 at 7:38 AM Poul-Henning Kamp phk@phk.freebsd.dk
wrote:

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