Electrostatic CRT Tester

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Grahame

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Dec 6, 2016, 4:39:07 PM12/6/16
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Here is a (not so very) sneak preview of a CRT Tester that Nick Stock and I have been working on. It will test a wide range of CRTs from "low voltage" types up to CRTs requiring 5kV (an add-on board takes that to 12kV). It has adjustable outputs for complex tubes with geometry electrodes and deflection blanking.



This is a prototype case - the final case will have laser engraved labels on the jacks.

<advert>Kits for the electronics and case available soon!</advert>

Grahame



David Forbes

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Dec 6, 2016, 4:48:16 PM12/6/16
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Grahame,

That looks like a nice gadget. I could use one to test all those CRTs piled up
in my store room. Especially the 7YP2.


On 12/6/2016 2:38 PM, 'Grahame' via neonixie-l wrote:
>
> Here is a (not so very) sneak preview of a CRT Tester that Nick Stock and I have
> been working on. It will test a wide range of CRTs from "low voltage" types up
> to CRTs requiring 5kV (an add-on board takes that to 12kV). It has adjustable
> outputs for complex tubes with geometry electrodes and deflection blanking.
>


--
David Forbes, Tucson, AZ

John Rehwinkel

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Dec 6, 2016, 5:02:48 PM12/6/16
to 'Grahame' via neonixie-l
> Here is a (not so very) sneak preview of a CRT Tester that Nick Stock and I have been working on. It will test a wide range of CRTs from "low voltage" types up to CRTs requiring 5kV (an add-on board takes that to 12kV). It has adjustable outputs for complex tubes with geometry electrodes and deflection blanking.

Oh, that's a thing of beauty! I too have a pile of CRTs from odd little viewfinder units to projection TV jugs. I've been working on lower voltage power supplies (500V-2kV) based on CCFL supplies and multipliers and higher voltage ones based on flyback transformers. A canned device like this would be a big aid in evaluating unknown CRTs and supplying missing voltages until I can get more dedicated supplies built.

It will help with the voltages for magnetic deflection and focus CRTs too, but obviously I'll need additional circuitry for them.

> <advert>Kits for the electronics and case available soon!</advert>

I'm looking forward to it! I looked at the tubetime boards (that's where I got the CCFL idea), but they don't quite meet my needs. I've been using David Forbes' Scope Clock as a CRT tester for a while, but it's aimed at common mid-sized CRTs, and I have a bunch of outliers.

- John

Samuel G. Guss

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Dec 6, 2016, 8:22:19 PM12/6/16
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Greetings All,

Grahame, that is one amazing looking device! Definitely be interested in
the kit!

All the best,
Sam


On 2016-12-06 16:38, the Renowned Grahame Marsh wrote:
> Here is a (not so very) sneak preview of a CRT Tester that Nick Stock
> and I have been working on. It will test a wide range of CRTs from
> "low voltage" types up to CRTs requiring 5kV (an add-on board takes
> that to 12kV). It has adjustable outputs for complex tubes with
> geometry electrodes and deflection blanking.
>
> This is a prototype case - the final case will have laser engraved
> labels on the jacks.
>
> <advert>Kits for the electronics and case available soon!</advert>
>
> Grahame
>
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Marcin Adamski

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Dec 6, 2016, 10:19:10 PM12/6/16
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I would be very interested, especially if I could use it on my 12 inch
tubes.
Marcin

Nicholas Stock

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Dec 6, 2016, 10:28:19 PM12/6/16
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Marcin, what 12 inch tubes do you have?

Nick

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Instrument Resources of America

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Dec 7, 2016, 12:26:59 AM12/7/16
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Nice job, but I've used, for many years now commercially available CRT testers aimed at the television market. They work very well, and will show gun emission, gas, leakage, and shorts. There isn't much else after that. Many have circuitry to remove shorts, and to boost emission, rejuvenate is the term that many of them use. The one's for color CRT's will check gun balance between the RGB guns. They can be had off of Ebay usually very inexpensive. I've even made a very simple adapter to check tubes, such as electrostatic tubes, and Tektronix and HP scope tubes as well. Burns on the screen can usually be seen with the naked eye without having the CRT actually lit up. By the way, has anyone here ever built, or know of, a 'scope clock' using either a small color CRT, or color television set?? Would make an interesting project for someone here perhaps. Ira.

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IRACOSALES.vcf

Grahame

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Dec 7, 2016, 2:48:53 AM12/7/16
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Hi everyone, thanks for your all your interests. The tester is aimed at not just showing the a dot can be obtained but being able to characterise a tube and look for demonstration of performance at datasheet conditions or to allow measurements to be made on an otherwise poorly documented tube. I have been using a scope clock and a Heathkit IP17 PSU to experiment with CRTs and wanted something closer to a single box.

No software! No microcontroller to burn!

The electronics design will be fully open (Eagle schematics, board layout and Gerbers). Kits will run as anything from minimal (custom parts only) to completely built and tested. Sold by me from Scotland.

The case is a mixture of 3D printed parts, cut/engraved acrylic and all the parts to put it together and will be sold separately by Nick from San Diego. The cut acrylic mechanical drawing are not owned by us but by the company making the acrylic parts. The 3D printed parts will be available as STL and Fusion 360 files.



Expect full details by mid January 2017 or perhaps sooner. PM me if you need something immediately and I'll try to help.

Grahame



Paolo Cravero

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Dec 7, 2016, 3:08:14 AM12/7/16
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Hello.

up. By the way, has anyone here ever built, or know of, a 'scope clock' using either a small color CRT, or color television set?? Would make an interesting project for someone here perhaps. Ira.

That's related to what I wanted to ask. I am about to replace the main home TV set, a 21" color CRT. Not a vintage part since it was build after year 2000, and bulky, but a CRT nevertheless. Is there any use of the color CRT tube or (parts of) the electronic internals?

As for building a "TV clock", the Rasperry Pi (first models) has an analog TV output and since it runs Linux it's a snap to get a clock screensaver. Not very cool, though!

Paolo

Marcin Adamski

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Dec 7, 2016, 7:41:26 AM12/7/16
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Hi Nick,
I have two Dumont K2261P7 and a Russian 31LO33V. Both types are
electrostatic and long persistence.
Marcin

Marcin Adamski

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Dec 7, 2016, 7:43:10 AM12/7/16
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No, sorry the Dumont is K2249P19, not K2261P7.

On 7/12/2016 14:28, Nicholas Stock wrote:

Nicholas Stock

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Dec 7, 2016, 10:24:56 AM12/7/16
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That's a beast! 10KV on the PDA. I'll let Grahame chime in on whether the add-on will work with that tube, but I think it should do. I have a couple of similar 12ACP19 tubes that I'm hoping to make a clock out of....not your average desk clock either..;-)

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Grahame

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Dec 7, 2016, 12:43:16 PM12/7/16
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Beast of a tube not a desk top clock indeed.

9.7kV on the PDA is "easy" enough. The other voltages 6.1kV accelerator, 1.5kV to 2.2kV focus, -130V to -200V grid is outside the range that the CRT Tester can operate and be used as a quantitative tool as it is aimed to be. It should be able to be qualitative manner to demonstrate the tube lights up and you can get a focused spot.

Grahame
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John Rehwinkel

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Dec 7, 2016, 12:57:56 PM12/7/16
to 'Grahame' via neonixie-l
> Marcin, what 12 inch tubes do you have?

I also have a 12" electrostatic deflection CRT, a Thomas K2261P7. I also have an oddball small one (also Thomas), a 1E36P20, which is a tiny electrostatic deflection unit with a 3/4" or so screen and, unusually, post deflection acceleration. I think it was built for a military helmet display or somesuch. It has a truly fine trace without the PDA hooked up. With the PDA, I'm guessing it combines a fine trace and high brightness.

- John

Grahame

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Dec 7, 2016, 1:27:42 PM12/7/16
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I have a 25mm electrostatic tube with a PDA (I need to dig it out to
tell you its number but I remember it has a CVxxxx number) - rather a
surprise when I pulled it out of its box. Also has a very fine trace.

Grahame

Marcin Adamski

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Dec 7, 2016, 5:44:44 PM12/7/16
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What I have in mind is a huge display (well, 12 inches ;)) showing
'Sauron eye' looking in the direction of an approaching person. The
orange long P19 phosphor would be perfect for that. Alternatively the
Matrix like effect with the clock face made of symbols brighter just
enough. And moving around. Saves from trace burnouts. Display activated
by motion/presence sensor. Otherwise HV off, filament at ~0.3 nominal.
My plan is to use raspberry pi for the logic. Deflection is a bit
tricky. 8bit DAC is not enough and what's really tricky is the
amplifiers able to deliver over 1kV. The 10kV acceleration seems
reasonably easy in comparison. Anyway, probably it will be maaany years
till I am able to dive into this project.
BTW, the Dumont tubes look very modern - flat screen, metalized - state
of the art. But the Russian has the real appeal - curved screen,
permanent hand writing, vintage shape of the funnel.

Marcin

On 08-Dec-16 02:24, Nicholas Stock wrote:
> That's a beast! 10KV on the PDA. I'll let Grahame chime in on whether
> the add-on will work with that tube, but I think it should do. I have a
> couple of similar 12ACP19 tubes that I'm hoping to make a clock out
> of....not your average desk clock either..;-)
>
> On Wed, Dec 7, 2016 at 4:43 AM, Marcin Adamski
> <marcin.r...@gmail.com <mailto:marcin.r...@gmail.com>> wrote:
>
> No, sorry the Dumont is K2249P19, not K2261P7.
>
> On 7/12/2016 14:28, Nicholas Stock wrote:
>
> Marcin, what 12 inch tubes do you have?
>
> Nick
>
>
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Instrument Resources of America

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Dec 7, 2016, 7:08:15 PM12/7/16
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I'm just making a wild guess here Marcin, what you may have is the
CRT used in the Hughes Aircraft Ground Systems Group, radar display
consoles which were part of a completely digital Navy Tactical Data
System from about the late 1950's.
http://ethw.org/First-Hand:Moving_the_Firing_Key_to_NTDS_-_Chapter_6_of_the_Story_of_the_Naval_Tactical_Data_System
Scroll down until you see the display consoles. When I was in the Navy,
a very long time ago, I worked on this system, although NOT the
displays. Ira.
IRACOSALES.vcf

Marcin Adamski

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Dec 8, 2016, 6:01:17 PM12/8/16
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Likely it could be. I had tough time finding any documentation on that
tube and finally asked for help the 'US Army Document Standardization
DLA Land and Maritime'. And they answered with the attached specs.
The SMC421290 is (to my knowledge) the same as NSN 5960-00-844-5225
which is MFG P/N K2249P19. To easy.

Thanks for the link, fantastic reading! Not to mention that the gear on
http://ethw.org/File:SWC_Console_.jpg looks way better than interiors of
the Millennium Falcon from Star Wars. ;)

Cheers!
Marcin
SM_C_421290.pdf
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