Looking for some info about RCA DTF numitrons

[Bartek Ogryz]

Hi!

They appeared on eBay last days: DTF137, DTF138, DTF140 (or maybe DTF/37, DTF/38, DTF/40). What are theese? Anyone has some more knowledge about them?

Bartek.

BTW: If someone is interested in numitrons, quite rare Apollo DA-2500 are hiding on eBay: item no 254866404573. Unfortunatelly, as the seller told me, all that have left, are without markings...

[Dekatron42]

Tubes designated DTF are development numbers used by Apollo/RCA - it says so at the bottom of their datasheets.

/Martin

[Dekatron42]

I knew I'd seen the number, and found them just now: http://www.tube-tester.com/sites/nixie/dat_arch/Numitron_RCA_01.pdf at the bottom of the page, they are development numbers for the DR2200 series.

/Martin

[Mark Moulding]

I have a pretty good sized collection of RCA DTF-104B Numitrons, which I think are especially attractive - they're large digits, in a flat-topped end-view tube.  They're quite rare now, and in fact I think I have most of the remaining world stock of these things (around 150 or so).  Although I've successfully used them in a couple of projects, I've never been able to locate a data sheet for them - does anyone have any pointers for this specific tube?

Thanks!
~~
Mark Moulding

[Nicholas Stock]

Er, you're not the only one with a stash of these.... :)

They are nice looking tubes...

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[Bartek Ogryz]

Thank you Martin!

What does it mean in practice? Are those just an old names of the same tubes, nowadays named DR22xx?

Sorry for banal question. I understand the words, but not the whole phrase.

Mark, those are beautifull, I won't be able to sleep now ;)

Bartek.

[Dekatron42]

I'd say that they are pre-production or engineering samples, tubes that are produced either for in house development or samples sent to presumptive buyers/customers who are interested in designing with them to release products as they become available in production volumes.

/Martin

[Mark Moulding]

Er, you're not the only one with a stash of these.... :)

I'm glad to hear that - it means that there will be other projects showing up with them.  One of the reasons I like Numitrons so much, besides being incredibly easy to drive, is their longevity.  At rated voltage (which I don't actually know for these tubes, but expect to be around 4.5V), they have a rated life of 100,000 hours, and that goes up rapidly to infinity at slightly lower voltages.  There's also no cathode poisoning or other issues to worry about.  This all means that I'm comfortable building something with the last of an unobtanium part, knowing that it won't need replacement in my lifetime.

~~
Mark Moulding

[peter bunge]

Would anyone care to sell me an end view Numitron (DTF104B) to add to my vintage digital working display?

I would also like a DIP 7 segment incandescent display, or anything interesting not in the picture. Nothing too new.

The LED Bargraph and Magic Eye react to ambient sound.

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[Audrey]

Aw that is quite a charming setup Peter 

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[Bartek Ogryz]

Martin, thank you for your detailed explanation! That's clear to me now.

Bartek.

[liam bartosiewicz]



That looks really nice, what does it do? If you’re interested in minitrons, you can find them in used avionic equipment.

On Oct 28, 2021, at 1:26 PM, peter bunge <bung...@gmail.com> wrote:



Would anyone care to sell me an end view Numitron (DTF104B) to add to my vintage digital working display?

I would also like a DIP 7 segment incandescent display, or anything interesting not in the picture. Nothing too new.

The LED Bargraph and Magic Eye react to ambient sound.

<20210803_093913.jpg>

[peter bunge]

It counts on the digital displays, scrolls text on an LED display, shows characters on the LED Matrix between scrolling through all 64 dots. 

CRTs were one of the earliest displays so I used a CRT clock kit bought on Ebay.

If anyone is interested I can send illustrated notes with schematics showing how each display is driven. Contact me private.

Peter

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[Bill van Dijk]

Hi Peter,

 

I had a look at my junk bin, and I have 20+ used (untested) DIP numitrons. There are 2 different sizes, one type is marked KW-615-17, the other KW-515. There are also some marked fdg-5v18.

 

If you are interested, I’ll charge $20 for my time packing it all up, plus my cost for mailing. The numitrons are free.

 

Let me know if you are interested, and PM me if you want to discuss.

 

Cheers, Bill

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[valve monky]

[newxito]

Nice job, that's a great looking clock!

valve monky schrieb am Freitag, 12. November 2021 um 17:25:44 UTC+1:

[Richard Scales]

I'm about to embark on a similar journey - I've gone for tighter tube spacing which I'm not 100% convinced will be right - time will tell.

- Richard

[Nicholas Stock]

Excellent stuff....those tubes look great.

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[Mark Moulding]

@Valve Monky: That's a nice-looking clock!  The beveled edges of the plywood give an attractive effect to a look I'm ordinarily not too fond of - nice job!

@Richard Scales: I assume this is a separate display board for a logic board somewhere else in the clock.  That's the approach I took, so that I can make different clock layouts without having to redesign the whole clock every time.  Regarding the tube spacing, I think you're going in the right direction - every time I moved them closer, the clock looked better.  This is a terrible picture, but the clock looks pretty nice in person...

Initially I put the drivers on the main board and used a ribbon cable to connect the two (I'm using 74LS595s to directly drive the filaments, non-multiplexed).  However, routing that wide cable turned into a hassle sometimes, so now I just have an eight-conductor cable (power, ground, shift clock, data, load strobe, output enable, colon, light sensor).  Of course, laying out the traces between the tubes and the drivers is almost the most tedious part, but they're not at all critical so I just let the PCB package take a stab at auto-routing - the result frequently looks ugly, but it changes a two-hour job into a three-minute one.

It turns out that sockets for the DTF-104Bs are still commonly available from the vintage audio dealers - they're 9-pin Novar/Magnoval sockets, such as this one.  If you lay out the board with larger pin holes, you can use point-to-point sockets like these as PCB mount.  Just make sure to have a tube in the socket when soldering onto the board, so that the pins are lined up correctly.

~~
Mark Moulding

[Richard Scales]

@Mark Moulding - actually - no - that's it, that's all there is. The logic is hiding on the back:

It consists of a WeMos D1 min micro controller which handles most everything. Individual TLC5916 drivers - one per tube then there is an optional DS3231 RTC which requires a battery to keep it going during power outage.

I have never actually bothered with fitting the RTC as the WeMos syncs the clock with NTP time.

There are connections for a button, a motion control device and there is a light dependant resistor which will dim the tubes when the ambient light decreases. All configuration is via a web gui - the software that runs everything is from Ian Sparks and has been used with his kind permission.

There are options for powering it via USB (that chunky rear entry socket type) or by 12V barrel connector (using a simple 12V to 5V module which behaves like a 7805 but is in fact a proper power supply inside).

There is also the option of under tube LED 'bling' which by default uses APA-106 LED's though I have made some tiny PCB's that will solder as APA-106 but actually have a WS2812B neopixel. It all depends on how far the nipple on the tubes extends into the hole that I have made for them.

The overall design should allow the construction of a fairly skinny case. 

- Richard

[valve monky]

photo of it rear

[Richard Scales]

Ah, OK, I can see what you did there - excellent. 

.... and you can see that I did mostly the same, I just modified the circuit board to fit the tubes - same software!

 - Richard

[valve monky]

hae you consider putting in rows of holes for pin headers so you could use it for remote tube sockets ?

[Richard Scales]

Yes, indeed I could do that - it would make the board a lot simpler though my regular train of thought is that I have to mount the tubes somehow so I might as well make it a single board to save all that wiring and space etc.

If there was ever a situation where remotely mounted tubes was a necessary thing then of course - a remote board could be made.

In the past I have used 2x6 IDC headers for nixies that require 11 connections. If one wanted to utilise the under tube led lighting on numitrons then a 2 x 6 also works there (8 for the numitron and 4 for the LED). This then requires a numitron mounting board -  one per numitron? which has the LED etc all mounted.

I would say though that IMHO - most situations would require the 6 numitrons to be positioned in a single row - so why not have everything on a single board?

Do you see an application for a remote board?

- Richard

[newxito]

Well, it's December soon, my favorite application for remote nixies/numitrons is making ornaments (balls) and hang them on the tree. A 4-digit clock in the tree looks very nice.

[Richard Scales]

Well, that's an interesting idea - and with some code adjustment - hanging numitrons would work just fine. 
I suspect that ribbon cable might not be the connection of choice  as you might want to match the tree decor, some bundle of green/dark wires might need to be utilised. 
In which case - for connections to the main board, would 0.1" male/female pins/sockets suffice?

- Richard

[Richard Scales]

... and would a hanging numitron require LED underlight - which would in fact be an LED overlight?

- Richard

On Tuesday, 16 November 2021 at 06:40:22 UTC newxito wrote:

[valve monky]

not a Christmas dangler decorations but the first version of the clock using the old board it ran on 12vac and was very basic

[newxito]

Some years ago, I made some ornaments using transparent plastic balls with an IN-18 inside. I did not use any underlight. I made the connections with ugly gray 12-conductor cables. Somebody in the group gave me the idea to hide the cables inside colored (green, brown, gold, …) cable sleeves. That was the solution to the main aesthetic problem. Hiding the controller was very easy :-)

Anyway, it would be nice to see some numitron decorations…

[Bill Notfaded]

Numitrons are awesome!  Driving them is so much easier than Nixie we all can relate to that.  I especially like the Russian Queen Numitron IV-13 and also IV-19's because they have the extra segments.  The Queens are sweet though when underlit with blue leds like here:  https://i.ebayimg.com/images/g/e1IAAOSw44dcA-TN/s-l1600.jpg and here:  https://i.ebayimg.com/images/g/LG0AAOSw3bZcA-Tg/s-l1600.jpg

I'm from USA so of course love the RCA and Apollo Numi's.

Bill

[Mark Moulding]

Oh, that's a pretty clock!  Considering that the tubes hover around $35-$50 each, $240 isn't a bad price.