Sperry radar clock now working!

[Morris Odell]

Hi all,

I've got the clock displaying time now. The video shows it upside down on the bench so it's at a few minutes past 12. That howling power transformer is a distraction, I'll have to wrap it in some sound absorbing material especially as I like to add Westminster chimes to my clocks :-).

The next step is to put it all together and tidy it up!

https://www.youtube.com/watch?v=tL3840bE9Cs

Morris

[Tom Harris]

Very nice Morris. The last display like this I saw had a rotating yoke with slip rings, so if yours has one the power transformer must be a real howler. It sounds like 400Hz too.

Can't wait to see it completed.

Tom Harris <celep...@gmail.com>

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[Tidak Ada]

Amazing!

Idea: Is it possible to give the hours hand a broader line?

 

I cannot wait to see extended technical information!

 

eric

---

From: neoni...@googlegroups.com [mailto:neoni...@googlegroups.com] On Behalf Of Morris Odell
Sent: maandag 14 juli 2014 11:03
To: neoni...@googlegroups.com
Subject: [neonixie-l] Sperry radar clock now working!

[NeonJohn]

That has to be the coolest scope clock I've seen in a long time. Well
done! The 400hz whine would send me through the roof, though.

John

On 07/14/2014 09:29 AM, neon...@gmail.com wrote:

> I've got the clock displaying time now. The video shows it upside down on
> the bench so it's at a few minutes past 12. That howling power transformer
> is a distraction, I'll have to wrap it in some sound absorbing material
> especially as I like to add Westminster chimes to my clocks :-).
>
> The next step is to put it all together and tidy it up!
>
> https://www.youtube.com/watch?v=tL3840bE9Cs
>
> Morris
>
>
>
>
>
>
>
>
>
>

--

John DeArmond
Tellico Plains, Occupied TN
http://www.fluxeon.com <-- THE source for induction heaters
http://www.neon-john.com <-- email from here
http://www.johndearmond.com <-- Best damned Blog on the net
PGP key: wwwkeys.pgp.net: BCB68D77

[Morris Odell]

Thanks all for your kind comments!

The 900 Hz howl is a disappointment. There are two 900 Hz transformers in there, the HV transformer is quiet and the power tranny is not.They have a tape wound core with the windings surrounding it.  I was wondering whether to try re-potting the noisy one. It would need some compound that was not too viscous so that it would run into any gaps. Unfortunately I don't have facilities for vacuum impregnation. Alternatively I could wrap it in some material and also put a layer of buffering material between it and the back chassis.

More progress reports will come as they happen!

Morris

[Morris Odell]

Thanks for the comment. It's hard to make the hands much thicker. It's radially scanned from the centre out so adding more scan lines makes the hand wider at the tip than at the base - the opposite of what's desirable. At the moment it's just 2 lines. I do increase the intensity for the minute and hour hands as much as I can compared to the second hand by increasing the time the dots making up the lines  are presented on the screen and it looks pretty good "in the flesh".

Morris

[Morris Odell]

Thanks Tom,

No it's a static yoke which is 3 phase delta wound and excited with suitable waveforms generated by a micro. It's the original 900 Hz radar power tranny that's the culprit.

BTW you may remember me as the fellow who once bought a E1T chassis from you for experimentation. That ended up as a the learning experience nice 6 digit clock too!

Cheers, 

[Tom Harris]

Hi Morris,

Yes I do, I follow you achievments with interest, where can I see pics of the E1T clock?

Your display sounds complex, a thee phase scanning yoke! Why not just have an X-Y vector display and drive that directly by the micro?

I do have a mate with a vacuum chamber (actually a commercial pressure cooker with a vacuum pump) and I can get hold of some transformer varnish as well. Want to give it a go? You have to bake it afterwards to get the varnish to go off. Lot of work for a one off.

In your profession I would have thought that you would have access to a lab with some sinister apparatus for preparation of "specimens" shall we say...?

Tom Harris <celep...@gmail.com>

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[yen...@internode.on.net]

The hand could be several lines starting short getting longer then shorter again?

Centrifuging could help with potting - ie bucket on a rope :-))

 

Maybe it is an excuse to try some active noise cancelling experiments?

Or, maybe you have had your fun and I'll give you two bob for it.....

John K 

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neoni...@googlegroups.com

To:

<neoni...@googlegroups.com>

Cc:

Sent:

Mon, 14 Jul 2014 19:58:06 -0700 (PDT)

Subject:

Re: [neonixie-l] Sperry radar clock now working!

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[Tidak Ada]

Would a slight focus variation during scanning the hours hands be an option?

Is there no transformer business available who can help you?

 

eric

---

From: neoni...@googlegroups.com [mailto:neoni...@googlegroups.com] On Behalf Of Morris Odell

Sent: dinsdag 15 juli 2014 4:58
To: neoni...@googlegroups.com
Subject: Re: [neonixie-l] Sperry radar clock now working!

To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/e07f7c29-3531-4a7f-9410-29d4cd951508%40googlegroups.com.

[Morris Odell]

Thanks Tom,

The E1T clock is at:

https://www.youtube.com/watch?v=J5I_L4KY4Qo

The video doesn't show it well but there's a little IN-17 nixie on the front that displays the number of satellites seen by the internal GPS receiver. It was a nice technical challenge but to be honest I don't think it succeeds as a clock. We humans are over-experienced to recognise traditional clockfaces and digital displays without actively thinking about them. The E1T is too alien. Non-nerds don't recognise it instantly as a clock as they do all the others I've made and even when it's explained people don't see it as a practical clock. 

Thanks for the offer of the transformer varnish etc. I've got a couple of other avenues to try (not work related :-) but I might get back to you.

Cheers,

Morris

[Oscilloclock]

Morris that is truly awesome. I admit to having no clue how this could work after all, and to having to go back and re-read your "Saga of the Sperry part 3" article - and I suspect I'll do so several times more before I "get it"!

Would a simple noise-canceling unit tuned to the transformer frequency help to reduce the noise?

Well done so far.

Aaron

[Instrument Resources of America]

The 900 Hz noise of which Morris is mentioning is 'most likely' being
caused by physical vibration of the lamination's within one or more of
the transformers, and there is not much that can be done about it, if I
am correct. But I'll wait and see along with the rest of us as to what
Morris has to say about it. Ira.

[yen...@internode.on.net]

Even when the laminations and windings are tight, magnetostriction can produce a lot of sound. A 'varnished' transformer can be potted in 'rubber' to absorb the vibrations. Mounting requirements and wire sizes are design issues.

John K 

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<neoni...@googlegroups.com>

Cc:

Sent:

Tue, 15 Jul 2014 06:36:39 -0700

Subject:

Re: [neonixie-l] Sperry radar clock now working!

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[Oscilloclock]

By "noise canceling", my crazy idea was something like this:

Attach a microphone on the transformer, apply a band-width filter at 900Hz, phase delay 180 degrees and output the amplified out-of-phase signal via a transducer or speaker mounted on the chassis.

Complete overkill, but could it possibly reduce a bit of the noise if the placement were just right?

Aaron

[Morris Odell]

Hi all,

Latest progress on the Sperry radar clock - I found a very helpful transformer manufacturing shop whose owner was happy to vacuum impregnate and bake the howling transformer for me. Alas, it only made a very small difference, if any. It sounds like the problem is magnetostriction in the core so there's no easy solution. I've rubber mounted it to try to stop the rear chassis panel from acting as a sounding board but that's all I can do I think. Hopefully it will be quieter when it's all buttoned up.

Right now I'm working on a PCB which will contain a PIR motion detector and also a Xbee wireless receiver to pick up the GPS data that I have sent  around my house. 

I also have a question - among other things the PIR motion detector switches the power to the CRT heater. Is it worth dribbling a little bit of current through the heater when it's off so that it heats up faster when the PIR senses an observer? If so, how much? The CRT heater draws 300 mA at 6.3 volts when it's working but takes about a minute to get to full emission. Will preheating it like that shorten its life significantly?

Any opinions much appreciated,

Thanks,  Morris

On Monday, July 14, 2014 7:02:47 PM UTC+10, Morris Odell wrote:

[Grahame Marsh]

Morris

Are you switching off the HT/EHT to the tube when the heater is off as well?  My understanding is that it is not good to switch the heater on while there is full HT on any thermal valve/tube. 

You might take the opportunity to "soft start" the CRT heater - I can PM you a schematic I'm using if you wish?

Cheers Grahame

On 10/08/2014 10:00, Morris Odell wrote:

Hi all,

Latest progress on the Sperry radar clock - I found a very helpful transformer manufacturing shop whose owner was happy to vacuum impregnate and bake the howling transformer for me. Alas, it only made a very small difference, if any. It sounds like the problem is magnetostriction in the core so there's no easy solution. I've rubber mounted it to try to stop the rear chassis panel from acting as a sounding board but that's all I can do I think. Hopefully it will be quieter when it's all buttoned up.

Right now I'm working on a PCB which will contain a PIR motion detector and also a Xbee wireless receiver to pick up the GPS data that I have sent  around my house. 

I also have a question - among other things the PIR motion detector switches the power to the CRT heater. Is it worth dribbling a little bit of current through the heater when it's off so that it heats up faster when the PIR senses an observer? If so, how much? The CRT heater draws 300 mA at 6.3 volts when it's working but takes about a minute to get to full emission. Will preheating it like that shorten its life significantly?

Any opinions much appreciated,

Thanks,  Morris

On Monday, July 14, 2014 7:02:47 PM UTC+10, Morris Odell wrote:

Hi all,

I've got the clock displaying time now. The video shows it upside down on the bench so it's at a few minutes past 12. That howling power transformer is a distraction, I'll have to wrap it in some sound absorbing material especially as I like to add Westminster chimes to my clocks :-).

The next step is to put it all together and tidy it up!

https://www.youtube.com/watch?v=tL3840bE9Cs

Morris

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[Tidak Ada]

Hi Morris,

 

Is the transformer sound also there if the steel case is removed? May be the case is working as a speaker membrane... In that case you can consider to make an aluminium or plastic case.

To muffle the sound you can use those bituminous plates also used for deadening resonance in car sheet work. 3M has them in their program and you will get them in most car parts shop and also damage repair business.

 

eric

 

 

---

From: neoni...@googlegroups.com [mailto:neoni...@googlegroups.com] On Behalf Of Morris Odell

Sent: zondag 10 augustus 2014 11:01
To: neoni...@googlegroups.com
Subject: [neonixie-l] Re: Sperry radar clock now working!

[Quixotic Nixotic]

Has anybody used this outfit for PCBs? Accutrace inc, trading as pcb4u.com.

http://www.pcb4u.com/a1ad77.asp

I am asking, because they are doing a US $30 + $10 FedEx shipping deal (is this US only?) on ten double side boards up to 20 square inches, 129 square centimetres. This seems a very attractive price.

John S

[Morris Odell]

Yes, I'm switching both the EHT and the heater. I would be surprised if cathode stripping is an issue considering the very small beam current in a CRT compared to, say, a power amp tube. Keeping the heater warm is a form of soft starting. I did that in my E1T clock where it starts from cold with about 60% heater voltage applied and then full HT and heater volts kick in about 10 seconds later. 

Morris

[Arne Rossius]

Hi,

Quixotic Nixotic wrote:
> Has anybody used this outfit for PCBs? Accutrace inc, trading as
> pcb4u.com.

[...]

> I am asking, because they are doing a US $30 + $10 FedEx shipping
> deal (is this US only?) on ten double side boards up to 20 square
> inches, 129 square centimetres. This seems a very attractive price.

I haven't used them, but if you don't mind ordering from China and
waiting a while for your boards, you can get them even cheaper. There
are a few suppliers with similar prices, I have used ITEAD
<http://imall.iteadstudio.com/open-pcb/pcb-prototyping.html> several
times. For ten double-sided 10cm x 10cm boards (about 4" x 4") with
green silkscreen, they ask 20 USD + shipping. I have found that shipping
is very cheap (less than 10 USD for 10 boards) if you choose Hongkong
Post, but takes 2-3 weeks (to Germany) in addition to about one week for
manufacturing, and you get (very basic) tracking. As far as I know,
shipping times to the US are similar.

The quality was usually very good, although in one case there was a
board with a clearly visible break in one of the trace, despite ordering
with "100% E-Test". I got 11 boards instead of 10 though.
Also the silkscreen isn't very high resolution and they put an order
code somewhere on the PCB, so if you need a board that *looks* perfect,
this one isn't right for you.

The other cheap chinese manufacturers I know of are
<https://www.seeedstudio.com/service/index.php?r=site/pcbService>
<http://www.tinyosshop.com/index.php?route=product/category&path=111>
<http://smart-prototyping.com/Prototyping-Services/Electronic-Prototyping/PCB-Prototyping.html>
<http://www.elecrow.com/special-offer-for-2-layer-1010cm-max-green-pcb-510pcs-p-761.html>
some of which are even cheaper than ITEAD in some cases, but I haven't
used any of those so far.


Best Regards,
Arne

[Grahame Marsh]

Yes, you know the problem, I hestated because there is so much mis-information on audio-fool sites.  I just tend to take a precautionary approach when I can to extending tube life.  But running the CRT heater warm is an alternative to full cold soft start.  My current scope clock which is under development switches the HT/EHT and the heater to off.  When it starts up (again PIR sensor) the heater takes 7 seconds to full voltage, then at 10 seconds the EHT is applied. The 7 seconds is set by a capacitor in the hardware, the 10 seconds is software controlled.

Grahame

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[Quixotic Nixotic]

On 10 Aug 2014, at 13:37, Arne Rossius wrote:

> Hi,
>
> Quixotic Nixotic wrote:
>> Has anybody used this outfit for PCBs? Accutrace inc, trading as
>> pcb4u.com.
> [...]
>> I am asking, because they are doing a US $30 + $10 FedEx shipping
>> deal (is this US only?) on ten double side boards up to 20 square
>> inches, 129 square centimetres. This seems a very attractive price.
>
> I haven't used them, but if you don't mind ordering from China and
> waiting a while for your boards, you can get them even cheaper. There
> are a few suppliers with similar prices, I have used ITEAD
> <http://imall.iteadstudio.com/open-pcb/pcb-prototyping.html> several
> times. For ten double-sided 10cm x 10cm boards (about 4" x 4") with
> green silkscreen, they ask 20 USD + shipping. I have found that shipping
> is very cheap (less than 10 USD for 10 boards) if you choose Hongkong
> Post, but takes 2-3 weeks (to Germany) in addition to about one week for
> manufacturing, and you get (very basic) tracking. As far as I know,
> shipping times to the US are similar.

Iteadstudio and Seeedstudio use the same fab house and I have used them both in the past and been very happy. The good deals they and others do are based on the 5cm x 5cm and 10cm x 10cm sizes - other sizes are much more expensive. Mitch Davis who runs Hackvana and is based in Shenzhen cannot quote me better deals than they do and says many houses match those 5x5 and 10x10 deals. Both those houses will be more expensive than pcb4u if I go over the 10cm x 10cm restriction.

I am working on a set of Doepfer format Eurorack sound modules and I cannot get six 16mm pots in a row on a 0.1" pitch in 10cms, I need 10.8cms, so the flexible sizing of pcb4u is appealing. Yes I know I can buy smaller pots, but then the pot cost goes up and the physical finger space around the knobs gets smaller.

I've asked about pcb4u shipping to UK and await their reply. Reading a review by someone, it says when you check out your order there is an offer of another ten boards at half price. Even more attractive if you need more than ten.

John S

[David Forbes]

On 8/10/14 2:00 AM, Morris Odell wrote:
>
> I also have a question - among other things the PIR motion detector
> switches the power to the CRT heater. Is it worth dribbling a little bit of
> current through the heater when it's off so that it heats up faster when
> the PIR senses an observer? If so, how much? The CRT heater draws 300 mA at
> 6.3 volts when it's working but takes about a minute to get to full
> emission. Will preheating it like that shorten its life significantly?
>
> Any opinions much appreciated,
>
> Thanks, Morris

Morris,

Most television sets made in the 1970s used a half-wave rectified
version of the 6.3VAC, applied to the heater continuously, for instant
start. I assume that they did enough study of the idea to ensure a
minimum of expensive warranty repairs.


--
David Forbes, Tucson AZ

[gregebert]

> I assume that they did enough study of the idea to ensure a minimum of expensive warranty repairs.

For consumer equipment, I always assumed keeping filaments always-on was a way for tube-sets to compete with increasing numbers of solid-state TVs that turned-on much faster. The "instant-on" tube sets definitely burned a fair amount of standby power (not exactly energy-star....). The funny thing is, it now takes a Windows-based computer more time to boot-up from power-on than any tube-based TV I ever owned.

Lab equipment, though, often had 3 power modes (off-standby-on), and I think the filaments-on mode served 2 purposes: (a) as you mentioned, for higher MTBF because filaments would not be temperature-cycled which causes shorter life via mechanical stress, and (b) eliminating warmup/stabilization time, which was often 30+ minutes.

Back to the original question of the radar-clock, I would keep a small amount of filament current, say 40-50% of nominal, if you plan to power-up the clock within the next day or so. Otherwise, I would do a soft-start AND soft-shutdown to slowly ramp the current to minimize the mechanical stress. It would be a real shame if the filament burned-out after you put so much time into making this truly amazing clock. Any chance you have a spare CRT ?

[Morris Odell]

Thanks to everyone who responded.It seems that the half wave diode trick is the way to go. Clocks using real nixies of course start instantly when the PIR triggers and you sort of expect that from other clocks too. The CRT is a 7ABP7A and they are not too hard to find. I think I have a spare anyway. I would like to avoid the starting inrush if possible by keeping the heater warm and a quick start is always good..

Totally OT but on that subject, I recently had to replace the lamp in our 30 year old fridge. It would have been pretty cold each time the power was applied and I estimate it withstood about 100,000 switch ons during its life. It will be interesting to see if its replacement is as reliable, if it is I'm unlikely to be around to see it!

Cheers,

Morris